This commit is contained in:
emile 2015-09-22 11:29:41 +02:00
parent 967e033b7e
commit 8825a26ae6
593 changed files with 88072 additions and 28 deletions

3
.gitignore vendored
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@ -5,3 +5,6 @@ log
*.iml *.iml
traefik traefik
traefik.toml traefik.toml
Godeps/_workspace/bin
Godeps/_workspace/pkg

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@ -1,3 +1,3 @@
FROM scratch FROM scratch
COPY dist/traefik_linux-386 /traefik COPY dist/traefik /
ENTRYPOINT ["/traefik"] ENTRYPOINT ["/traefik"]

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{
"ImportPath": "github.com/emilevauge/traefik",
"GoVersion": "go1.5",
"Packages": [
"./..."
],
"Deps": [
{
"ImportPath": "github.com/BurntSushi/toml",
"Rev": "bd2bdf7f18f849530ef7a1c29a4290217cab32a1"
},
{
"ImportPath": "github.com/BurntSushi/ty",
"Rev": "6add9cd6ad42d389d6ead1dde60b4ad71e46fd74"
},
{
"ImportPath": "github.com/alecthomas/template",
"Rev": "b867cc6ab45cece8143cfcc6fc9c77cf3f2c23c0"
},
{
"ImportPath": "github.com/alecthomas/units",
"Rev": "6b4e7dc5e3143b85ea77909c72caf89416fc2915"
},
{
"ImportPath": "github.com/cenkalti/backoff",
"Rev": "4dc77674aceaabba2c7e3da25d4c823edfb73f99"
},
{
"ImportPath": "github.com/codahale/hdrhistogram",
"Rev": "954f16e8b9ef0e5d5189456aa4c1202758e04f17"
},
{
"ImportPath": "github.com/codegangsta/negroni",
"Comment": "v0.1-70-gc7477ad",
"Rev": "c7477ad8e330bef55bf1ebe300cf8aa67c492d1b"
},
{
"ImportPath": "github.com/elazarl/go-bindata-assetfs",
"Rev": "d5cac425555ca5cf00694df246e04f05e6a55150"
},
{
"ImportPath": "github.com/fsouza/go-dockerclient",
"Rev": "0239034d42f665efa17fd77c39f891c2f9f32922"
},
{
"ImportPath": "github.com/gambol99/go-marathon",
"Rev": "0ba31bcb0d7633ba1888d744c42990eb15281cf1"
},
{
"ImportPath": "github.com/gorilla/context",
"Rev": "215affda49addc4c8ef7e2534915df2c8c35c6cd"
},
{
"ImportPath": "github.com/gorilla/handlers",
"Rev": "40694b40f4a928c062f56849989d3e9cd0570e5f"
},
{
"ImportPath": "github.com/gorilla/mux",
"Rev": "f15e0c49460fd49eebe2bcc8486b05d1bef68d3a"
},
{
"ImportPath": "github.com/hashicorp/consul/api",
"Comment": "v0.5.2-313-gde08067",
"Rev": "de080672fee9e6104572eeea89eccdca135bb918"
},
{
"ImportPath": "github.com/mailgun/log",
"Rev": "44874009257d4d47ba9806f1b7f72a32a015e4d8"
},
{
"ImportPath": "github.com/mailgun/oxy/cbreaker",
"Rev": "547c334d658398c05b346c0b79d8f47ba2e1473b"
},
{
"ImportPath": "github.com/mailgun/oxy/forward",
"Rev": "547c334d658398c05b346c0b79d8f47ba2e1473b"
},
{
"ImportPath": "github.com/mailgun/oxy/memmetrics",
"Rev": "547c334d658398c05b346c0b79d8f47ba2e1473b"
},
{
"ImportPath": "github.com/mailgun/oxy/roundrobin",
"Rev": "547c334d658398c05b346c0b79d8f47ba2e1473b"
},
{
"ImportPath": "github.com/mailgun/oxy/utils",
"Rev": "547c334d658398c05b346c0b79d8f47ba2e1473b"
},
{
"ImportPath": "github.com/mailgun/predicate",
"Rev": "cb0bff91a7ab7cf7571e661ff883fc997bc554a3"
},
{
"ImportPath": "github.com/mailgun/timetools",
"Rev": "fd192d755b00c968d312d23f521eb0cdc6f66bd0"
},
{
"ImportPath": "github.com/op/go-logging",
"Rev": "e8d5414f0947014548c2334044a0fac13187dfee"
},
{
"ImportPath": "github.com/thoas/stats",
"Rev": "54ed61c2b47e263ae2f01b86837b0c4bd1da28e8"
},
{
"ImportPath": "github.com/tylerb/graceful",
"Comment": "v1.2.1",
"Rev": "ac9ebe4f1ee151ac1eeeaef32957085cba64d508"
},
{
"ImportPath": "github.com/unrolled/render",
"Rev": "26b4e3aac686940fe29521545afad9966ddfc80c"
},
{
"ImportPath": "golang.org/x/net/netutil",
"Rev": "d9558e5c97f85372afee28cf2b6059d7d3818919"
},
{
"ImportPath": "gopkg.in/alecthomas/kingpin.v2",
"Comment": "v2.0.12",
"Rev": "639879d6110b1b0409410c7b737ef0bb18325038"
},
{
"ImportPath": "gopkg.in/fsnotify.v1",
"Comment": "v1.2.0",
"Rev": "96c060f6a6b7e0d6f75fddd10efeaca3e5d1bcb0"
},
{
"ImportPath": "gopkg.in/mgo.v2/bson",
"Comment": "r2015.06.03-5-g22287ba",
"Rev": "22287bab4379e1fbf6002fb4eb769888f3fb224c"
}
]
}

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This directory tree is generated automatically by godep.
Please do not edit.
See https://github.com/tools/godep for more information.

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/pkg
/bin

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TAGS
tags
.*.swp
tomlcheck/tomlcheck
toml.test

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language: go
go:
- 1.1
- 1.2
- tip
install:
- go install ./...
- go get github.com/BurntSushi/toml-test
script:
- export PATH="$PATH:$HOME/gopath/bin"
- make test

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Compatible with TOML version
[v0.2.0](https://github.com/mojombo/toml/blob/master/versions/toml-v0.2.0.md)

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DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
Version 2, December 2004
Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>
Everyone is permitted to copy and distribute verbatim or modified
copies of this license document, and changing it is allowed as long
as the name is changed.
DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. You just DO WHAT THE FUCK YOU WANT TO.

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install:
go install ./...
test: install
go test -v
toml-test toml-test-decoder
toml-test -encoder toml-test-encoder
fmt:
gofmt -w *.go */*.go
colcheck *.go */*.go
tags:
find ./ -name '*.go' -print0 | xargs -0 gotags > TAGS
push:
git push origin master
git push github master

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## TOML parser and encoder for Go with reflection
TOML stands for Tom's Obvious, Minimal Language. This Go package provides a
reflection interface similar to Go's standard library `json` and `xml`
packages. This package also supports the `encoding.TextUnmarshaler` and
`encoding.TextMarshaler` interfaces so that you can define custom data
representations. (There is an example of this below.)
Spec: https://github.com/mojombo/toml
Compatible with TOML version
[v0.2.0](https://github.com/mojombo/toml/blob/master/versions/toml-v0.2.0.md)
Documentation: http://godoc.org/github.com/BurntSushi/toml
Installation:
```bash
go get github.com/BurntSushi/toml
```
Try the toml validator:
```bash
go get github.com/BurntSushi/toml/cmd/tomlv
tomlv some-toml-file.toml
```
[![Build status](https://api.travis-ci.org/BurntSushi/toml.png)](https://travis-ci.org/BurntSushi/toml)
### Testing
This package passes all tests in
[toml-test](https://github.com/BurntSushi/toml-test) for both the decoder
and the encoder.
### Examples
This package works similarly to how the Go standard library handles `XML`
and `JSON`. Namely, data is loaded into Go values via reflection.
For the simplest example, consider some TOML file as just a list of keys
and values:
```toml
Age = 25
Cats = [ "Cauchy", "Plato" ]
Pi = 3.14
Perfection = [ 6, 28, 496, 8128 ]
DOB = 1987-07-05T05:45:00Z
```
Which could be defined in Go as:
```go
type Config struct {
Age int
Cats []string
Pi float64
Perfection []int
DOB time.Time // requires `import time`
}
```
And then decoded with:
```go
var conf Config
if _, err := toml.Decode(tomlData, &conf); err != nil {
// handle error
}
```
You can also use struct tags if your struct field name doesn't map to a TOML
key value directly:
```toml
some_key_NAME = "wat"
```
```go
type TOML struct {
ObscureKey string `toml:"some_key_NAME"`
}
```
### Using the `encoding.TextUnmarshaler` interface
Here's an example that automatically parses duration strings into
`time.Duration` values:
```toml
[[song]]
name = "Thunder Road"
duration = "4m49s"
[[song]]
name = "Stairway to Heaven"
duration = "8m03s"
```
Which can be decoded with:
```go
type song struct {
Name string
Duration duration
}
type songs struct {
Song []song
}
var favorites songs
if _, err := Decode(blob, &favorites); err != nil {
log.Fatal(err)
}
for _, s := range favorites.Song {
fmt.Printf("%s (%s)\n", s.Name, s.Duration)
}
```
And you'll also need a `duration` type that satisfies the
`encoding.TextUnmarshaler` interface:
```go
type duration struct {
time.Duration
}
func (d *duration) UnmarshalText(text []byte) error {
var err error
d.Duration, err = time.ParseDuration(string(text))
return err
}
```
### More complex usage
Here's an example of how to load the example from the official spec page:
```toml
# This is a TOML document. Boom.
title = "TOML Example"
[owner]
name = "Tom Preston-Werner"
organization = "GitHub"
bio = "GitHub Cofounder & CEO\nLikes tater tots and beer."
dob = 1979-05-27T07:32:00Z # First class dates? Why not?
[database]
server = "192.168.1.1"
ports = [ 8001, 8001, 8002 ]
connection_max = 5000
enabled = true
[servers]
# You can indent as you please. Tabs or spaces. TOML don't care.
[servers.alpha]
ip = "10.0.0.1"
dc = "eqdc10"
[servers.beta]
ip = "10.0.0.2"
dc = "eqdc10"
[clients]
data = [ ["gamma", "delta"], [1, 2] ] # just an update to make sure parsers support it
# Line breaks are OK when inside arrays
hosts = [
"alpha",
"omega"
]
```
And the corresponding Go types are:
```go
type tomlConfig struct {
Title string
Owner ownerInfo
DB database `toml:"database"`
Servers map[string]server
Clients clients
}
type ownerInfo struct {
Name string
Org string `toml:"organization"`
Bio string
DOB time.Time
}
type database struct {
Server string
Ports []int
ConnMax int `toml:"connection_max"`
Enabled bool
}
type server struct {
IP string
DC string
}
type clients struct {
Data [][]interface{}
Hosts []string
}
```
Note that a case insensitive match will be tried if an exact match can't be
found.
A working example of the above can be found in `_examples/example.{go,toml}`.

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DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
Version 2, December 2004
Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>
Everyone is permitted to copy and distribute verbatim or modified
copies of this license document, and changing it is allowed as long
as the name is changed.
DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. You just DO WHAT THE FUCK YOU WANT TO.

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@ -0,0 +1,14 @@
# Implements the TOML test suite interface
This is an implementation of the interface expected by
[toml-test](https://github.com/BurntSushi/toml-test) for my
[toml parser written in Go](https://github.com/BurntSushi/toml).
In particular, it maps TOML data on `stdin` to a JSON format on `stdout`.
Compatible with TOML version
[v0.2.0](https://github.com/mojombo/toml/blob/master/versions/toml-v0.2.0.md)
Compatible with `toml-test` version
[v0.2.0](https://github.com/BurntSushi/toml-test/tree/v0.2.0)

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// Command toml-test-decoder satisfies the toml-test interface for testing
// TOML decoders. Namely, it accepts TOML on stdin and outputs JSON on stdout.
package main
import (
"encoding/json"
"flag"
"fmt"
"log"
"os"
"path"
"time"
"github.com/BurntSushi/toml"
)
func init() {
log.SetFlags(0)
flag.Usage = usage
flag.Parse()
}
func usage() {
log.Printf("Usage: %s < toml-file\n", path.Base(os.Args[0]))
flag.PrintDefaults()
os.Exit(1)
}
func main() {
if flag.NArg() != 0 {
flag.Usage()
}
var tmp interface{}
if _, err := toml.DecodeReader(os.Stdin, &tmp); err != nil {
log.Fatalf("Error decoding TOML: %s", err)
}
typedTmp := translate(tmp)
if err := json.NewEncoder(os.Stdout).Encode(typedTmp); err != nil {
log.Fatalf("Error encoding JSON: %s", err)
}
}
func translate(tomlData interface{}) interface{} {
switch orig := tomlData.(type) {
case map[string]interface{}:
typed := make(map[string]interface{}, len(orig))
for k, v := range orig {
typed[k] = translate(v)
}
return typed
case []map[string]interface{}:
typed := make([]map[string]interface{}, len(orig))
for i, v := range orig {
typed[i] = translate(v).(map[string]interface{})
}
return typed
case []interface{}:
typed := make([]interface{}, len(orig))
for i, v := range orig {
typed[i] = translate(v)
}
// We don't really need to tag arrays, but let's be future proof.
// (If TOML ever supports tuples, we'll need this.)
return tag("array", typed)
case time.Time:
return tag("datetime", orig.Format("2006-01-02T15:04:05Z"))
case bool:
return tag("bool", fmt.Sprintf("%v", orig))
case int64:
return tag("integer", fmt.Sprintf("%d", orig))
case float64:
return tag("float", fmt.Sprintf("%v", orig))
case string:
return tag("string", orig)
}
panic(fmt.Sprintf("Unknown type: %T", tomlData))
}
func tag(typeName string, data interface{}) map[string]interface{} {
return map[string]interface{}{
"type": typeName,
"value": data,
}
}

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DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
Version 2, December 2004
Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>
Everyone is permitted to copy and distribute verbatim or modified
copies of this license document, and changing it is allowed as long
as the name is changed.
DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. You just DO WHAT THE FUCK YOU WANT TO.

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@ -0,0 +1,14 @@
# Implements the TOML test suite interface for TOML encoders
This is an implementation of the interface expected by
[toml-test](https://github.com/BurntSushi/toml-test) for the
[TOML encoder](https://github.com/BurntSushi/toml).
In particular, it maps JSON data on `stdin` to a TOML format on `stdout`.
Compatible with TOML version
[v0.2.0](https://github.com/mojombo/toml/blob/master/versions/toml-v0.2.0.md)
Compatible with `toml-test` version
[v0.2.0](https://github.com/BurntSushi/toml-test/tree/v0.2.0)

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// Command toml-test-encoder satisfies the toml-test interface for testing
// TOML encoders. Namely, it accepts JSON on stdin and outputs TOML on stdout.
package main
import (
"encoding/json"
"flag"
"log"
"os"
"path"
"strconv"
"time"
"github.com/BurntSushi/toml"
)
func init() {
log.SetFlags(0)
flag.Usage = usage
flag.Parse()
}
func usage() {
log.Printf("Usage: %s < json-file\n", path.Base(os.Args[0]))
flag.PrintDefaults()
os.Exit(1)
}
func main() {
if flag.NArg() != 0 {
flag.Usage()
}
var tmp interface{}
if err := json.NewDecoder(os.Stdin).Decode(&tmp); err != nil {
log.Fatalf("Error decoding JSON: %s", err)
}
tomlData := translate(tmp)
if err := toml.NewEncoder(os.Stdout).Encode(tomlData); err != nil {
log.Fatalf("Error encoding TOML: %s", err)
}
}
func translate(typedJson interface{}) interface{} {
switch v := typedJson.(type) {
case map[string]interface{}:
if len(v) == 2 && in("type", v) && in("value", v) {
return untag(v)
}
m := make(map[string]interface{}, len(v))
for k, v2 := range v {
m[k] = translate(v2)
}
return m
case []interface{}:
tabArray := make([]map[string]interface{}, len(v))
for i := range v {
if m, ok := translate(v[i]).(map[string]interface{}); ok {
tabArray[i] = m
} else {
log.Fatalf("JSON arrays may only contain objects. This " +
"corresponds to only tables being allowed in " +
"TOML table arrays.")
}
}
return tabArray
}
log.Fatalf("Unrecognized JSON format '%T'.", typedJson)
panic("unreachable")
}
func untag(typed map[string]interface{}) interface{} {
t := typed["type"].(string)
v := typed["value"]
switch t {
case "string":
return v.(string)
case "integer":
v := v.(string)
n, err := strconv.Atoi(v)
if err != nil {
log.Fatalf("Could not parse '%s' as integer: %s", v, err)
}
return n
case "float":
v := v.(string)
f, err := strconv.ParseFloat(v, 64)
if err != nil {
log.Fatalf("Could not parse '%s' as float64: %s", v, err)
}
return f
case "datetime":
v := v.(string)
t, err := time.Parse("2006-01-02T15:04:05Z", v)
if err != nil {
log.Fatalf("Could not parse '%s' as a datetime: %s", v, err)
}
return t
case "bool":
v := v.(string)
switch v {
case "true":
return true
case "false":
return false
}
log.Fatalf("Could not parse '%s' as a boolean.", v)
case "array":
v := v.([]interface{})
array := make([]interface{}, len(v))
for i := range v {
if m, ok := v[i].(map[string]interface{}); ok {
array[i] = untag(m)
} else {
log.Fatalf("Arrays may only contain other arrays or "+
"primitive values, but found a '%T'.", m)
}
}
return array
}
log.Fatalf("Unrecognized tag type '%s'.", t)
panic("unreachable")
}
func in(key string, m map[string]interface{}) bool {
_, ok := m[key]
return ok
}

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DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
Version 2, December 2004
Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>
Everyone is permitted to copy and distribute verbatim or modified
copies of this license document, and changing it is allowed as long
as the name is changed.
DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. You just DO WHAT THE FUCK YOU WANT TO.

View file

@ -0,0 +1,22 @@
# TOML Validator
If Go is installed, it's simple to try it out:
```bash
go get github.com/BurntSushi/toml/cmd/tomlv
tomlv some-toml-file.toml
```
You can see the types of every key in a TOML file with:
```bash
tomlv -types some-toml-file.toml
```
At the moment, only one error message is reported at a time. Error messages
include line numbers. No output means that the files given are valid TOML, or
there is a bug in `tomlv`.
Compatible with TOML version
[v0.1.0](https://github.com/mojombo/toml/blob/master/versions/toml-v0.1.0.md)

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// Command tomlv validates TOML documents and prints each key's type.
package main
import (
"flag"
"fmt"
"log"
"os"
"path"
"strings"
"text/tabwriter"
"github.com/BurntSushi/toml"
)
var (
flagTypes = false
)
func init() {
log.SetFlags(0)
flag.BoolVar(&flagTypes, "types", flagTypes,
"When set, the types of every defined key will be shown.")
flag.Usage = usage
flag.Parse()
}
func usage() {
log.Printf("Usage: %s toml-file [ toml-file ... ]\n",
path.Base(os.Args[0]))
flag.PrintDefaults()
os.Exit(1)
}
func main() {
if flag.NArg() < 1 {
flag.Usage()
}
for _, f := range flag.Args() {
var tmp interface{}
md, err := toml.DecodeFile(f, &tmp)
if err != nil {
log.Fatalf("Error in '%s': %s", f, err)
}
if flagTypes {
printTypes(md)
}
}
}
func printTypes(md toml.MetaData) {
tabw := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
for _, key := range md.Keys() {
fmt.Fprintf(tabw, "%s%s\t%s\n",
strings.Repeat(" ", len(key)-1), key, md.Type(key...))
}
tabw.Flush()
}

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package toml
import (
"fmt"
"io"
"io/ioutil"
"math"
"reflect"
"strings"
"time"
)
var e = fmt.Errorf
// Primitive is a TOML value that hasn't been decoded into a Go value.
// When using the various `Decode*` functions, the type `Primitive` may
// be given to any value, and its decoding will be delayed.
//
// A `Primitive` value can be decoded using the `PrimitiveDecode` function.
//
// The underlying representation of a `Primitive` value is subject to change.
// Do not rely on it.
//
// N.B. Primitive values are still parsed, so using them will only avoid
// the overhead of reflection. They can be useful when you don't know the
// exact type of TOML data until run time.
type Primitive struct {
undecoded interface{}
context Key
}
// DEPRECATED!
//
// Use MetaData.PrimitiveDecode instead.
func PrimitiveDecode(primValue Primitive, v interface{}) error {
md := MetaData{decoded: make(map[string]bool)}
return md.unify(primValue.undecoded, rvalue(v))
}
// PrimitiveDecode is just like the other `Decode*` functions, except it
// decodes a TOML value that has already been parsed. Valid primitive values
// can *only* be obtained from values filled by the decoder functions,
// including this method. (i.e., `v` may contain more `Primitive`
// values.)
//
// Meta data for primitive values is included in the meta data returned by
// the `Decode*` functions with one exception: keys returned by the Undecoded
// method will only reflect keys that were decoded. Namely, any keys hidden
// behind a Primitive will be considered undecoded. Executing this method will
// update the undecoded keys in the meta data. (See the example.)
func (md *MetaData) PrimitiveDecode(primValue Primitive, v interface{}) error {
md.context = primValue.context
defer func() { md.context = nil }()
return md.unify(primValue.undecoded, rvalue(v))
}
// Decode will decode the contents of `data` in TOML format into a pointer
// `v`.
//
// TOML hashes correspond to Go structs or maps. (Dealer's choice. They can be
// used interchangeably.)
//
// TOML arrays of tables correspond to either a slice of structs or a slice
// of maps.
//
// TOML datetimes correspond to Go `time.Time` values.
//
// All other TOML types (float, string, int, bool and array) correspond
// to the obvious Go types.
//
// An exception to the above rules is if a type implements the
// encoding.TextUnmarshaler interface. In this case, any primitive TOML value
// (floats, strings, integers, booleans and datetimes) will be converted to
// a byte string and given to the value's UnmarshalText method. See the
// Unmarshaler example for a demonstration with time duration strings.
//
// Key mapping
//
// TOML keys can map to either keys in a Go map or field names in a Go
// struct. The special `toml` struct tag may be used to map TOML keys to
// struct fields that don't match the key name exactly. (See the example.)
// A case insensitive match to struct names will be tried if an exact match
// can't be found.
//
// The mapping between TOML values and Go values is loose. That is, there
// may exist TOML values that cannot be placed into your representation, and
// there may be parts of your representation that do not correspond to
// TOML values. This loose mapping can be made stricter by using the IsDefined
// and/or Undecoded methods on the MetaData returned.
//
// This decoder will not handle cyclic types. If a cyclic type is passed,
// `Decode` will not terminate.
func Decode(data string, v interface{}) (MetaData, error) {
p, err := parse(data)
if err != nil {
return MetaData{}, err
}
md := MetaData{
p.mapping, p.types, p.ordered,
make(map[string]bool, len(p.ordered)), nil,
}
return md, md.unify(p.mapping, rvalue(v))
}
// DecodeFile is just like Decode, except it will automatically read the
// contents of the file at `fpath` and decode it for you.
func DecodeFile(fpath string, v interface{}) (MetaData, error) {
bs, err := ioutil.ReadFile(fpath)
if err != nil {
return MetaData{}, err
}
return Decode(string(bs), v)
}
// DecodeReader is just like Decode, except it will consume all bytes
// from the reader and decode it for you.
func DecodeReader(r io.Reader, v interface{}) (MetaData, error) {
bs, err := ioutil.ReadAll(r)
if err != nil {
return MetaData{}, err
}
return Decode(string(bs), v)
}
// unify performs a sort of type unification based on the structure of `rv`,
// which is the client representation.
//
// Any type mismatch produces an error. Finding a type that we don't know
// how to handle produces an unsupported type error.
func (md *MetaData) unify(data interface{}, rv reflect.Value) error {
// Special case. Look for a `Primitive` value.
if rv.Type() == reflect.TypeOf((*Primitive)(nil)).Elem() {
// Save the undecoded data and the key context into the primitive
// value.
context := make(Key, len(md.context))
copy(context, md.context)
rv.Set(reflect.ValueOf(Primitive{
undecoded: data,
context: context,
}))
return nil
}
// Special case. Handle time.Time values specifically.
// TODO: Remove this code when we decide to drop support for Go 1.1.
// This isn't necessary in Go 1.2 because time.Time satisfies the encoding
// interfaces.
if rv.Type().AssignableTo(rvalue(time.Time{}).Type()) {
return md.unifyDatetime(data, rv)
}
// Special case. Look for a value satisfying the TextUnmarshaler interface.
if v, ok := rv.Interface().(TextUnmarshaler); ok {
return md.unifyText(data, v)
}
// BUG(burntsushi)
// The behavior here is incorrect whenever a Go type satisfies the
// encoding.TextUnmarshaler interface but also corresponds to a TOML
// hash or array. In particular, the unmarshaler should only be applied
// to primitive TOML values. But at this point, it will be applied to
// all kinds of values and produce an incorrect error whenever those values
// are hashes or arrays (including arrays of tables).
k := rv.Kind()
// laziness
if k >= reflect.Int && k <= reflect.Uint64 {
return md.unifyInt(data, rv)
}
switch k {
case reflect.Ptr:
elem := reflect.New(rv.Type().Elem())
err := md.unify(data, reflect.Indirect(elem))
if err != nil {
return err
}
rv.Set(elem)
return nil
case reflect.Struct:
return md.unifyStruct(data, rv)
case reflect.Map:
return md.unifyMap(data, rv)
case reflect.Array:
return md.unifyArray(data, rv)
case reflect.Slice:
return md.unifySlice(data, rv)
case reflect.String:
return md.unifyString(data, rv)
case reflect.Bool:
return md.unifyBool(data, rv)
case reflect.Interface:
// we only support empty interfaces.
if rv.NumMethod() > 0 {
return e("Unsupported type '%s'.", rv.Kind())
}
return md.unifyAnything(data, rv)
case reflect.Float32:
fallthrough
case reflect.Float64:
return md.unifyFloat64(data, rv)
}
return e("Unsupported type '%s'.", rv.Kind())
}
func (md *MetaData) unifyStruct(mapping interface{}, rv reflect.Value) error {
tmap, ok := mapping.(map[string]interface{})
if !ok {
return mismatch(rv, "map", mapping)
}
for key, datum := range tmap {
var f *field
fields := cachedTypeFields(rv.Type())
for i := range fields {
ff := &fields[i]
if ff.name == key {
f = ff
break
}
if f == nil && strings.EqualFold(ff.name, key) {
f = ff
}
}
if f != nil {
subv := rv
for _, i := range f.index {
subv = indirect(subv.Field(i))
}
if isUnifiable(subv) {
md.decoded[md.context.add(key).String()] = true
md.context = append(md.context, key)
if err := md.unify(datum, subv); err != nil {
return e("Type mismatch for '%s.%s': %s",
rv.Type().String(), f.name, err)
}
md.context = md.context[0 : len(md.context)-1]
} else if f.name != "" {
// Bad user! No soup for you!
return e("Field '%s.%s' is unexported, and therefore cannot "+
"be loaded with reflection.", rv.Type().String(), f.name)
}
}
}
return nil
}
func (md *MetaData) unifyMap(mapping interface{}, rv reflect.Value) error {
tmap, ok := mapping.(map[string]interface{})
if !ok {
return badtype("map", mapping)
}
if rv.IsNil() {
rv.Set(reflect.MakeMap(rv.Type()))
}
for k, v := range tmap {
md.decoded[md.context.add(k).String()] = true
md.context = append(md.context, k)
rvkey := indirect(reflect.New(rv.Type().Key()))
rvval := reflect.Indirect(reflect.New(rv.Type().Elem()))
if err := md.unify(v, rvval); err != nil {
return err
}
md.context = md.context[0 : len(md.context)-1]
rvkey.SetString(k)
rv.SetMapIndex(rvkey, rvval)
}
return nil
}
func (md *MetaData) unifyArray(data interface{}, rv reflect.Value) error {
datav := reflect.ValueOf(data)
if datav.Kind() != reflect.Slice {
return badtype("slice", data)
}
sliceLen := datav.Len()
if sliceLen != rv.Len() {
return e("expected array length %d; got TOML array of length %d",
rv.Len(), sliceLen)
}
return md.unifySliceArray(datav, rv)
}
func (md *MetaData) unifySlice(data interface{}, rv reflect.Value) error {
datav := reflect.ValueOf(data)
if datav.Kind() != reflect.Slice {
return badtype("slice", data)
}
sliceLen := datav.Len()
if rv.IsNil() {
rv.Set(reflect.MakeSlice(rv.Type(), sliceLen, sliceLen))
}
return md.unifySliceArray(datav, rv)
}
func (md *MetaData) unifySliceArray(data, rv reflect.Value) error {
sliceLen := data.Len()
for i := 0; i < sliceLen; i++ {
v := data.Index(i).Interface()
sliceval := indirect(rv.Index(i))
if err := md.unify(v, sliceval); err != nil {
return err
}
}
return nil
}
func (md *MetaData) unifyDatetime(data interface{}, rv reflect.Value) error {
if _, ok := data.(time.Time); ok {
rv.Set(reflect.ValueOf(data))
return nil
}
return badtype("time.Time", data)
}
func (md *MetaData) unifyString(data interface{}, rv reflect.Value) error {
if s, ok := data.(string); ok {
rv.SetString(s)
return nil
}
return badtype("string", data)
}
func (md *MetaData) unifyFloat64(data interface{}, rv reflect.Value) error {
if num, ok := data.(float64); ok {
switch rv.Kind() {
case reflect.Float32:
fallthrough
case reflect.Float64:
rv.SetFloat(num)
default:
panic("bug")
}
return nil
}
return badtype("float", data)
}
func (md *MetaData) unifyInt(data interface{}, rv reflect.Value) error {
if num, ok := data.(int64); ok {
if rv.Kind() >= reflect.Int && rv.Kind() <= reflect.Int64 {
switch rv.Kind() {
case reflect.Int, reflect.Int64:
// No bounds checking necessary.
case reflect.Int8:
if num < math.MinInt8 || num > math.MaxInt8 {
return e("Value '%d' is out of range for int8.", num)
}
case reflect.Int16:
if num < math.MinInt16 || num > math.MaxInt16 {
return e("Value '%d' is out of range for int16.", num)
}
case reflect.Int32:
if num < math.MinInt32 || num > math.MaxInt32 {
return e("Value '%d' is out of range for int32.", num)
}
}
rv.SetInt(num)
} else if rv.Kind() >= reflect.Uint && rv.Kind() <= reflect.Uint64 {
unum := uint64(num)
switch rv.Kind() {
case reflect.Uint, reflect.Uint64:
// No bounds checking necessary.
case reflect.Uint8:
if num < 0 || unum > math.MaxUint8 {
return e("Value '%d' is out of range for uint8.", num)
}
case reflect.Uint16:
if num < 0 || unum > math.MaxUint16 {
return e("Value '%d' is out of range for uint16.", num)
}
case reflect.Uint32:
if num < 0 || unum > math.MaxUint32 {
return e("Value '%d' is out of range for uint32.", num)
}
}
rv.SetUint(unum)
} else {
panic("unreachable")
}
return nil
}
return badtype("integer", data)
}
func (md *MetaData) unifyBool(data interface{}, rv reflect.Value) error {
if b, ok := data.(bool); ok {
rv.SetBool(b)
return nil
}
return badtype("boolean", data)
}
func (md *MetaData) unifyAnything(data interface{}, rv reflect.Value) error {
rv.Set(reflect.ValueOf(data))
return nil
}
func (md *MetaData) unifyText(data interface{}, v TextUnmarshaler) error {
var s string
switch sdata := data.(type) {
case TextMarshaler:
text, err := sdata.MarshalText()
if err != nil {
return err
}
s = string(text)
case fmt.Stringer:
s = sdata.String()
case string:
s = sdata
case bool:
s = fmt.Sprintf("%v", sdata)
case int64:
s = fmt.Sprintf("%d", sdata)
case float64:
s = fmt.Sprintf("%f", sdata)
default:
return badtype("primitive (string-like)", data)
}
if err := v.UnmarshalText([]byte(s)); err != nil {
return err
}
return nil
}
// rvalue returns a reflect.Value of `v`. All pointers are resolved.
func rvalue(v interface{}) reflect.Value {
return indirect(reflect.ValueOf(v))
}
// indirect returns the value pointed to by a pointer.
// Pointers are followed until the value is not a pointer.
// New values are allocated for each nil pointer.
//
// An exception to this rule is if the value satisfies an interface of
// interest to us (like encoding.TextUnmarshaler).
func indirect(v reflect.Value) reflect.Value {
if v.Kind() != reflect.Ptr {
if v.CanAddr() {
pv := v.Addr()
if _, ok := pv.Interface().(TextUnmarshaler); ok {
return pv
}
}
return v
}
if v.IsNil() {
v.Set(reflect.New(v.Type().Elem()))
}
return indirect(reflect.Indirect(v))
}
func isUnifiable(rv reflect.Value) bool {
if rv.CanSet() {
return true
}
if _, ok := rv.Interface().(TextUnmarshaler); ok {
return true
}
return false
}
func badtype(expected string, data interface{}) error {
return e("Expected %s but found '%T'.", expected, data)
}
func mismatch(user reflect.Value, expected string, data interface{}) error {
return e("Type mismatch for %s. Expected %s but found '%T'.",
user.Type().String(), expected, data)
}

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@ -0,0 +1,99 @@
package toml
import "strings"
// MetaData allows access to meta information about TOML data that may not
// be inferrable via reflection. In particular, whether a key has been defined
// and the TOML type of a key.
type MetaData struct {
mapping map[string]interface{}
types map[string]tomlType
keys []Key
decoded map[string]bool
context Key // Used only during decoding.
}
// IsDefined returns true if the key given exists in the TOML data. The key
// should be specified hierarchially. e.g.,
//
// // access the TOML key 'a.b.c'
// IsDefined("a", "b", "c")
//
// IsDefined will return false if an empty key given. Keys are case sensitive.
func (md *MetaData) IsDefined(key ...string) bool {
if len(key) == 0 {
return false
}
var hash map[string]interface{}
var ok bool
var hashOrVal interface{} = md.mapping
for _, k := range key {
if hash, ok = hashOrVal.(map[string]interface{}); !ok {
return false
}
if hashOrVal, ok = hash[k]; !ok {
return false
}
}
return true
}
// Type returns a string representation of the type of the key specified.
//
// Type will return the empty string if given an empty key or a key that
// does not exist. Keys are case sensitive.
func (md *MetaData) Type(key ...string) string {
fullkey := strings.Join(key, ".")
if typ, ok := md.types[fullkey]; ok {
return typ.typeString()
}
return ""
}
// Key is the type of any TOML key, including key groups. Use (MetaData).Keys
// to get values of this type.
type Key []string
func (k Key) String() string {
return strings.Join(k, ".")
}
func (k Key) add(piece string) Key {
newKey := make(Key, len(k)+1)
copy(newKey, k)
newKey[len(k)] = piece
return newKey
}
// Keys returns a slice of every key in the TOML data, including key groups.
// Each key is itself a slice, where the first element is the top of the
// hierarchy and the last is the most specific.
//
// The list will have the same order as the keys appeared in the TOML data.
//
// All keys returned are non-empty.
func (md *MetaData) Keys() []Key {
return md.keys
}
// Undecoded returns all keys that have not been decoded in the order in which
// they appear in the original TOML document.
//
// This includes keys that haven't been decoded because of a Primitive value.
// Once the Primitive value is decoded, the keys will be considered decoded.
//
// Also note that decoding into an empty interface will result in no decoding,
// and so no keys will be considered decoded.
//
// In this sense, the Undecoded keys correspond to keys in the TOML document
// that do not have a concrete type in your representation.
func (md *MetaData) Undecoded() []Key {
undecoded := make([]Key, 0, len(md.keys))
for _, key := range md.keys {
if !md.decoded[key.String()] {
undecoded = append(undecoded, key)
}
}
return undecoded
}

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@ -0,0 +1,540 @@
package toml
import (
"fmt"
"log"
"reflect"
"testing"
"time"
)
func init() {
log.SetFlags(0)
}
func TestDecodeSimple(t *testing.T) {
var testSimple = `
age = 250
andrew = "gallant"
kait = "brady"
now = 1987-07-05T05:45:00Z
yesOrNo = true
pi = 3.14
colors = [
["red", "green", "blue"],
["cyan", "magenta", "yellow", "black"],
]
[My.Cats]
plato = "cat 1"
cauchy = "cat 2"
`
type cats struct {
Plato string
Cauchy string
}
type simple struct {
Age int
Colors [][]string
Pi float64
YesOrNo bool
Now time.Time
Andrew string
Kait string
My map[string]cats
}
var val simple
_, err := Decode(testSimple, &val)
if err != nil {
t.Fatal(err)
}
now, err := time.Parse("2006-01-02T15:04:05", "1987-07-05T05:45:00")
if err != nil {
panic(err)
}
var answer = simple{
Age: 250,
Andrew: "gallant",
Kait: "brady",
Now: now,
YesOrNo: true,
Pi: 3.14,
Colors: [][]string{
{"red", "green", "blue"},
{"cyan", "magenta", "yellow", "black"},
},
My: map[string]cats{
"Cats": cats{Plato: "cat 1", Cauchy: "cat 2"},
},
}
if !reflect.DeepEqual(val, answer) {
t.Fatalf("Expected\n-----\n%#v\n-----\nbut got\n-----\n%#v\n",
answer, val)
}
}
func TestDecodeEmbedded(t *testing.T) {
type Dog struct{ Name string }
type Age int
tests := map[string]struct {
input string
decodeInto interface{}
wantDecoded interface{}
}{
"embedded struct": {
input: `Name = "milton"`,
decodeInto: &struct{ Dog }{},
wantDecoded: &struct{ Dog }{Dog{"milton"}},
},
"embedded non-nil pointer to struct": {
input: `Name = "milton"`,
decodeInto: &struct{ *Dog }{},
wantDecoded: &struct{ *Dog }{&Dog{"milton"}},
},
"embedded nil pointer to struct": {
input: ``,
decodeInto: &struct{ *Dog }{},
wantDecoded: &struct{ *Dog }{nil},
},
"embedded int": {
input: `Age = -5`,
decodeInto: &struct{ Age }{},
wantDecoded: &struct{ Age }{-5},
},
}
for label, test := range tests {
_, err := Decode(test.input, test.decodeInto)
if err != nil {
t.Fatal(err)
}
if !reflect.DeepEqual(test.wantDecoded, test.decodeInto) {
t.Errorf("%s: want decoded == %+v, got %+v",
label, test.wantDecoded, test.decodeInto)
}
}
}
func TestTableArrays(t *testing.T) {
var tomlTableArrays = `
[[albums]]
name = "Born to Run"
[[albums.songs]]
name = "Jungleland"
[[albums.songs]]
name = "Meeting Across the River"
[[albums]]
name = "Born in the USA"
[[albums.songs]]
name = "Glory Days"
[[albums.songs]]
name = "Dancing in the Dark"
`
type Song struct {
Name string
}
type Album struct {
Name string
Songs []Song
}
type Music struct {
Albums []Album
}
expected := Music{[]Album{
{"Born to Run", []Song{{"Jungleland"}, {"Meeting Across the River"}}},
{"Born in the USA", []Song{{"Glory Days"}, {"Dancing in the Dark"}}},
}}
var got Music
if _, err := Decode(tomlTableArrays, &got); err != nil {
t.Fatal(err)
}
if !reflect.DeepEqual(expected, got) {
t.Fatalf("\n%#v\n!=\n%#v\n", expected, got)
}
}
// Case insensitive matching tests.
// A bit more comprehensive than needed given the current implementation,
// but implementations change.
// Probably still missing demonstrations of some ugly corner cases regarding
// case insensitive matching and multiple fields.
func TestCase(t *testing.T) {
var caseToml = `
tOpString = "string"
tOpInt = 1
tOpFloat = 1.1
tOpBool = true
tOpdate = 2006-01-02T15:04:05Z
tOparray = [ "array" ]
Match = "i should be in Match only"
MatcH = "i should be in MatcH only"
once = "just once"
[nEst.eD]
nEstedString = "another string"
`
type InsensitiveEd struct {
NestedString string
}
type InsensitiveNest struct {
Ed InsensitiveEd
}
type Insensitive struct {
TopString string
TopInt int
TopFloat float64
TopBool bool
TopDate time.Time
TopArray []string
Match string
MatcH string
Once string
OncE string
Nest InsensitiveNest
}
tme, err := time.Parse(time.RFC3339, time.RFC3339[:len(time.RFC3339)-5])
if err != nil {
panic(err)
}
expected := Insensitive{
TopString: "string",
TopInt: 1,
TopFloat: 1.1,
TopBool: true,
TopDate: tme,
TopArray: []string{"array"},
MatcH: "i should be in MatcH only",
Match: "i should be in Match only",
Once: "just once",
OncE: "",
Nest: InsensitiveNest{
Ed: InsensitiveEd{NestedString: "another string"},
},
}
var got Insensitive
if _, err := Decode(caseToml, &got); err != nil {
t.Fatal(err)
}
if !reflect.DeepEqual(expected, got) {
t.Fatalf("\n%#v\n!=\n%#v\n", expected, got)
}
}
func TestPointers(t *testing.T) {
type Object struct {
Type string
Description string
}
type Dict struct {
NamedObject map[string]*Object
BaseObject *Object
Strptr *string
Strptrs []*string
}
s1, s2, s3 := "blah", "abc", "def"
expected := &Dict{
Strptr: &s1,
Strptrs: []*string{&s2, &s3},
NamedObject: map[string]*Object{
"foo": {"FOO", "fooooo!!!"},
"bar": {"BAR", "ba-ba-ba-ba-barrrr!!!"},
},
BaseObject: &Object{"BASE", "da base"},
}
ex1 := `
Strptr = "blah"
Strptrs = ["abc", "def"]
[NamedObject.foo]
Type = "FOO"
Description = "fooooo!!!"
[NamedObject.bar]
Type = "BAR"
Description = "ba-ba-ba-ba-barrrr!!!"
[BaseObject]
Type = "BASE"
Description = "da base"
`
dict := new(Dict)
_, err := Decode(ex1, dict)
if err != nil {
t.Errorf("Decode error: %v", err)
}
if !reflect.DeepEqual(expected, dict) {
t.Fatalf("\n%#v\n!=\n%#v\n", expected, dict)
}
}
type sphere struct {
Center [3]float64
Radius float64
}
func TestDecodeSimpleArray(t *testing.T) {
var s1 sphere
if _, err := Decode(`center = [0.0, 1.5, 0.0]`, &s1); err != nil {
t.Fatal(err)
}
}
func TestDecodeArrayWrongSize(t *testing.T) {
var s1 sphere
if _, err := Decode(`center = [0.1, 2.3]`, &s1); err == nil {
t.Fatal("Expected array type mismatch error")
}
}
func TestDecodeLargeIntoSmallInt(t *testing.T) {
type table struct {
Value int8
}
var tab table
if _, err := Decode(`value = 500`, &tab); err == nil {
t.Fatal("Expected integer out-of-bounds error.")
}
}
func TestDecodeSizedInts(t *testing.T) {
type table struct {
U8 uint8
U16 uint16
U32 uint32
U64 uint64
U uint
I8 int8
I16 int16
I32 int32
I64 int64
I int
}
answer := table{1, 1, 1, 1, 1, -1, -1, -1, -1, -1}
toml := `
u8 = 1
u16 = 1
u32 = 1
u64 = 1
u = 1
i8 = -1
i16 = -1
i32 = -1
i64 = -1
i = -1
`
var tab table
if _, err := Decode(toml, &tab); err != nil {
t.Fatal(err.Error())
}
if answer != tab {
t.Fatalf("Expected %#v but got %#v", answer, tab)
}
}
func ExampleMetaData_PrimitiveDecode() {
var md MetaData
var err error
var tomlBlob = `
ranking = ["Springsteen", "J Geils"]
[bands.Springsteen]
started = 1973
albums = ["Greetings", "WIESS", "Born to Run", "Darkness"]
[bands.J Geils]
started = 1970
albums = ["The J. Geils Band", "Full House", "Blow Your Face Out"]
`
type band struct {
Started int
Albums []string
}
type classics struct {
Ranking []string
Bands map[string]Primitive
}
// Do the initial decode. Reflection is delayed on Primitive values.
var music classics
if md, err = Decode(tomlBlob, &music); err != nil {
log.Fatal(err)
}
// MetaData still includes information on Primitive values.
fmt.Printf("Is `bands.Springsteen` defined? %v\n",
md.IsDefined("bands", "Springsteen"))
// Decode primitive data into Go values.
for _, artist := range music.Ranking {
// A band is a primitive value, so we need to decode it to get a
// real `band` value.
primValue := music.Bands[artist]
var aBand band
if err = md.PrimitiveDecode(primValue, &aBand); err != nil {
log.Fatal(err)
}
fmt.Printf("%s started in %d.\n", artist, aBand.Started)
}
// Check to see if there were any fields left undecoded.
// Note that this won't be empty before decoding the Primitive value!
fmt.Printf("Undecoded: %q\n", md.Undecoded())
// Output:
// Is `bands.Springsteen` defined? true
// Springsteen started in 1973.
// J Geils started in 1970.
// Undecoded: []
}
func ExampleDecode() {
var tomlBlob = `
# Some comments.
[alpha]
ip = "10.0.0.1"
[alpha.config]
Ports = [ 8001, 8002 ]
Location = "Toronto"
Created = 1987-07-05T05:45:00Z
[beta]
ip = "10.0.0.2"
[beta.config]
Ports = [ 9001, 9002 ]
Location = "New Jersey"
Created = 1887-01-05T05:55:00Z
`
type serverConfig struct {
Ports []int
Location string
Created time.Time
}
type server struct {
IP string `toml:"ip"`
Config serverConfig `toml:"config"`
}
type servers map[string]server
var config servers
if _, err := Decode(tomlBlob, &config); err != nil {
log.Fatal(err)
}
for _, name := range []string{"alpha", "beta"} {
s := config[name]
fmt.Printf("Server: %s (ip: %s) in %s created on %s\n",
name, s.IP, s.Config.Location,
s.Config.Created.Format("2006-01-02"))
fmt.Printf("Ports: %v\n", s.Config.Ports)
}
// Output:
// Server: alpha (ip: 10.0.0.1) in Toronto created on 1987-07-05
// Ports: [8001 8002]
// Server: beta (ip: 10.0.0.2) in New Jersey created on 1887-01-05
// Ports: [9001 9002]
}
type duration struct {
time.Duration
}
func (d *duration) UnmarshalText(text []byte) error {
var err error
d.Duration, err = time.ParseDuration(string(text))
return err
}
// Example Unmarshaler shows how to decode TOML strings into your own
// custom data type.
func Example_unmarshaler() {
blob := `
[[song]]
name = "Thunder Road"
duration = "4m49s"
[[song]]
name = "Stairway to Heaven"
duration = "8m03s"
`
type song struct {
Name string
Duration duration
}
type songs struct {
Song []song
}
var favorites songs
if _, err := Decode(blob, &favorites); err != nil {
log.Fatal(err)
}
// Code to implement the TextUnmarshaler interface for `duration`:
//
// type duration struct {
// time.Duration
// }
//
// func (d *duration) UnmarshalText(text []byte) error {
// var err error
// d.Duration, err = time.ParseDuration(string(text))
// return err
// }
for _, s := range favorites.Song {
fmt.Printf("%s (%s)\n", s.Name, s.Duration)
}
// Output:
// Thunder Road (4m49s)
// Stairway to Heaven (8m3s)
}
// Example StrictDecoding shows how to detect whether there are keys in the
// TOML document that weren't decoded into the value given. This is useful
// for returning an error to the user if they've included extraneous fields
// in their configuration.
func Example_strictDecoding() {
var blob = `
key1 = "value1"
key2 = "value2"
key3 = "value3"
`
type config struct {
Key1 string
Key3 string
}
var conf config
md, err := Decode(blob, &conf)
if err != nil {
log.Fatal(err)
}
fmt.Printf("Undecoded keys: %q\n", md.Undecoded())
// Output:
// Undecoded keys: ["key2"]
}

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@ -0,0 +1,27 @@
/*
Package toml provides facilities for decoding and encoding TOML configuration
files via reflection. There is also support for delaying decoding with
the Primitive type, and querying the set of keys in a TOML document with the
MetaData type.
The specification implemented: https://github.com/mojombo/toml
The sub-command github.com/BurntSushi/toml/cmd/tomlv can be used to verify
whether a file is a valid TOML document. It can also be used to print the
type of each key in a TOML document.
Testing
There are two important types of tests used for this package. The first is
contained inside '*_test.go' files and uses the standard Go unit testing
framework. These tests are primarily devoted to holistically testing the
decoder and encoder.
The second type of testing is used to verify the implementation's adherence
to the TOML specification. These tests have been factored into their own
project: https://github.com/BurntSushi/toml-test
The reason the tests are in a separate project is so that they can be used by
any implementation of TOML. Namely, it is language agnostic.
*/
package toml

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@ -0,0 +1,521 @@
package toml
import (
"bufio"
"errors"
"fmt"
"io"
"reflect"
"sort"
"strconv"
"strings"
"time"
"unicode"
)
type tomlEncodeError struct{ error }
var (
errArrayMixedElementTypes = errors.New(
"can't encode array with mixed element types")
errArrayNilElement = errors.New(
"can't encode array with nil element")
errNonString = errors.New(
"can't encode a map with non-string key type")
errAnonNonStruct = errors.New(
"can't encode an anonymous field that is not a struct")
errArrayNoTable = errors.New(
"TOML array element can't contain a table")
errNoKey = errors.New(
"top-level values must be a Go map or struct")
errAnything = errors.New("") // used in testing
)
var quotedReplacer = strings.NewReplacer(
"\t", "\\t",
"\n", "\\n",
"\r", "\\r",
"\"", "\\\"",
"\\", "\\\\",
)
// Encoder controls the encoding of Go values to a TOML document to some
// io.Writer.
//
// The indentation level can be controlled with the Indent field.
type Encoder struct {
// A single indentation level. By default it is two spaces.
Indent string
// hasWritten is whether we have written any output to w yet.
hasWritten bool
w *bufio.Writer
}
// NewEncoder returns a TOML encoder that encodes Go values to the io.Writer
// given. By default, a single indentation level is 2 spaces.
func NewEncoder(w io.Writer) *Encoder {
return &Encoder{
w: bufio.NewWriter(w),
Indent: " ",
}
}
// Encode writes a TOML representation of the Go value to the underlying
// io.Writer. If the value given cannot be encoded to a valid TOML document,
// then an error is returned.
//
// The mapping between Go values and TOML values should be precisely the same
// as for the Decode* functions. Similarly, the TextMarshaler interface is
// supported by encoding the resulting bytes as strings. (If you want to write
// arbitrary binary data then you will need to use something like base64 since
// TOML does not have any binary types.)
//
// When encoding TOML hashes (i.e., Go maps or structs), keys without any
// sub-hashes are encoded first.
//
// If a Go map is encoded, then its keys are sorted alphabetically for
// deterministic output. More control over this behavior may be provided if
// there is demand for it.
//
// Encoding Go values without a corresponding TOML representation---like map
// types with non-string keys---will cause an error to be returned. Similarly
// for mixed arrays/slices, arrays/slices with nil elements, embedded
// non-struct types and nested slices containing maps or structs.
// (e.g., [][]map[string]string is not allowed but []map[string]string is OK
// and so is []map[string][]string.)
func (enc *Encoder) Encode(v interface{}) error {
rv := eindirect(reflect.ValueOf(v))
if err := enc.safeEncode(Key([]string{}), rv); err != nil {
return err
}
return enc.w.Flush()
}
func (enc *Encoder) safeEncode(key Key, rv reflect.Value) (err error) {
defer func() {
if r := recover(); r != nil {
if terr, ok := r.(tomlEncodeError); ok {
err = terr.error
return
}
panic(r)
}
}()
enc.encode(key, rv)
return nil
}
func (enc *Encoder) encode(key Key, rv reflect.Value) {
// Special case. Time needs to be in ISO8601 format.
// Special case. If we can marshal the type to text, then we used that.
// Basically, this prevents the encoder for handling these types as
// generic structs (or whatever the underlying type of a TextMarshaler is).
switch rv.Interface().(type) {
case time.Time, TextMarshaler:
enc.keyEqElement(key, rv)
return
}
k := rv.Kind()
switch k {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32,
reflect.Uint64,
reflect.Float32, reflect.Float64, reflect.String, reflect.Bool:
enc.keyEqElement(key, rv)
case reflect.Array, reflect.Slice:
if typeEqual(tomlArrayHash, tomlTypeOfGo(rv)) {
enc.eArrayOfTables(key, rv)
} else {
enc.keyEqElement(key, rv)
}
case reflect.Interface:
if rv.IsNil() {
return
}
enc.encode(key, rv.Elem())
case reflect.Map:
if rv.IsNil() {
return
}
enc.eTable(key, rv)
case reflect.Ptr:
if rv.IsNil() {
return
}
enc.encode(key, rv.Elem())
case reflect.Struct:
enc.eTable(key, rv)
default:
panic(e("Unsupported type for key '%s': %s", key, k))
}
}
// eElement encodes any value that can be an array element (primitives and
// arrays).
func (enc *Encoder) eElement(rv reflect.Value) {
switch v := rv.Interface().(type) {
case time.Time:
// Special case time.Time as a primitive. Has to come before
// TextMarshaler below because time.Time implements
// encoding.TextMarshaler, but we need to always use UTC.
enc.wf(v.In(time.FixedZone("UTC", 0)).Format("2006-01-02T15:04:05Z"))
return
case TextMarshaler:
// Special case. Use text marshaler if it's available for this value.
if s, err := v.MarshalText(); err != nil {
encPanic(err)
} else {
enc.writeQuoted(string(s))
}
return
}
switch rv.Kind() {
case reflect.Bool:
enc.wf(strconv.FormatBool(rv.Bool()))
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
enc.wf(strconv.FormatInt(rv.Int(), 10))
case reflect.Uint, reflect.Uint8, reflect.Uint16,
reflect.Uint32, reflect.Uint64:
enc.wf(strconv.FormatUint(rv.Uint(), 10))
case reflect.Float32:
enc.wf(floatAddDecimal(strconv.FormatFloat(rv.Float(), 'f', -1, 32)))
case reflect.Float64:
enc.wf(floatAddDecimal(strconv.FormatFloat(rv.Float(), 'f', -1, 64)))
case reflect.Array, reflect.Slice:
enc.eArrayOrSliceElement(rv)
case reflect.Interface:
enc.eElement(rv.Elem())
case reflect.String:
enc.writeQuoted(rv.String())
default:
panic(e("Unexpected primitive type: %s", rv.Kind()))
}
}
// By the TOML spec, all floats must have a decimal with at least one
// number on either side.
func floatAddDecimal(fstr string) string {
if !strings.Contains(fstr, ".") {
return fstr + ".0"
}
return fstr
}
func (enc *Encoder) writeQuoted(s string) {
enc.wf("\"%s\"", quotedReplacer.Replace(s))
}
func (enc *Encoder) eArrayOrSliceElement(rv reflect.Value) {
length := rv.Len()
enc.wf("[")
for i := 0; i < length; i++ {
elem := rv.Index(i)
enc.eElement(elem)
if i != length-1 {
enc.wf(", ")
}
}
enc.wf("]")
}
func (enc *Encoder) eArrayOfTables(key Key, rv reflect.Value) {
if len(key) == 0 {
encPanic(errNoKey)
}
panicIfInvalidKey(key, true)
for i := 0; i < rv.Len(); i++ {
trv := rv.Index(i)
if isNil(trv) {
continue
}
enc.newline()
enc.wf("%s[[%s]]", enc.indentStr(key), key.String())
enc.newline()
enc.eMapOrStruct(key, trv)
}
}
func (enc *Encoder) eTable(key Key, rv reflect.Value) {
if len(key) == 1 {
// Output an extra new line between top-level tables.
// (The newline isn't written if nothing else has been written though.)
enc.newline()
}
if len(key) > 0 {
panicIfInvalidKey(key, true)
enc.wf("%s[%s]", enc.indentStr(key), key.String())
enc.newline()
}
enc.eMapOrStruct(key, rv)
}
func (enc *Encoder) eMapOrStruct(key Key, rv reflect.Value) {
switch rv := eindirect(rv); rv.Kind() {
case reflect.Map:
enc.eMap(key, rv)
case reflect.Struct:
enc.eStruct(key, rv)
default:
panic("eTable: unhandled reflect.Value Kind: " + rv.Kind().String())
}
}
func (enc *Encoder) eMap(key Key, rv reflect.Value) {
rt := rv.Type()
if rt.Key().Kind() != reflect.String {
encPanic(errNonString)
}
// Sort keys so that we have deterministic output. And write keys directly
// underneath this key first, before writing sub-structs or sub-maps.
var mapKeysDirect, mapKeysSub []string
for _, mapKey := range rv.MapKeys() {
k := mapKey.String()
if typeIsHash(tomlTypeOfGo(rv.MapIndex(mapKey))) {
mapKeysSub = append(mapKeysSub, k)
} else {
mapKeysDirect = append(mapKeysDirect, k)
}
}
var writeMapKeys = func(mapKeys []string) {
sort.Strings(mapKeys)
for _, mapKey := range mapKeys {
mrv := rv.MapIndex(reflect.ValueOf(mapKey))
if isNil(mrv) {
// Don't write anything for nil fields.
continue
}
enc.encode(key.add(mapKey), mrv)
}
}
writeMapKeys(mapKeysDirect)
writeMapKeys(mapKeysSub)
}
func (enc *Encoder) eStruct(key Key, rv reflect.Value) {
// Write keys for fields directly under this key first, because if we write
// a field that creates a new table, then all keys under it will be in that
// table (not the one we're writing here).
rt := rv.Type()
var fieldsDirect, fieldsSub [][]int
var addFields func(rt reflect.Type, rv reflect.Value, start []int)
addFields = func(rt reflect.Type, rv reflect.Value, start []int) {
for i := 0; i < rt.NumField(); i++ {
f := rt.Field(i)
// skip unexporded fields
if f.PkgPath != "" {
continue
}
frv := rv.Field(i)
if f.Anonymous {
frv := eindirect(frv)
t := frv.Type()
if t.Kind() != reflect.Struct {
encPanic(errAnonNonStruct)
}
addFields(t, frv, f.Index)
} else if typeIsHash(tomlTypeOfGo(frv)) {
fieldsSub = append(fieldsSub, append(start, f.Index...))
} else {
fieldsDirect = append(fieldsDirect, append(start, f.Index...))
}
}
}
addFields(rt, rv, nil)
var writeFields = func(fields [][]int) {
for _, fieldIndex := range fields {
sft := rt.FieldByIndex(fieldIndex)
sf := rv.FieldByIndex(fieldIndex)
if isNil(sf) {
// Don't write anything for nil fields.
continue
}
keyName := sft.Tag.Get("toml")
if keyName == "-" {
continue
}
if keyName == "" {
keyName = sft.Name
}
enc.encode(key.add(keyName), sf)
}
}
writeFields(fieldsDirect)
writeFields(fieldsSub)
}
// tomlTypeName returns the TOML type name of the Go value's type. It is used to
// determine whether the types of array elements are mixed (which is forbidden).
// If the Go value is nil, then it is illegal for it to be an array element, and
// valueIsNil is returned as true.
// Returns the TOML type of a Go value. The type may be `nil`, which means
// no concrete TOML type could be found.
func tomlTypeOfGo(rv reflect.Value) tomlType {
if isNil(rv) || !rv.IsValid() {
return nil
}
switch rv.Kind() {
case reflect.Bool:
return tomlBool
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32,
reflect.Uint64:
return tomlInteger
case reflect.Float32, reflect.Float64:
return tomlFloat
case reflect.Array, reflect.Slice:
if typeEqual(tomlHash, tomlArrayType(rv)) {
return tomlArrayHash
} else {
return tomlArray
}
case reflect.Ptr, reflect.Interface:
return tomlTypeOfGo(rv.Elem())
case reflect.String:
return tomlString
case reflect.Map:
return tomlHash
case reflect.Struct:
switch rv.Interface().(type) {
case time.Time:
return tomlDatetime
case TextMarshaler:
return tomlString
default:
return tomlHash
}
default:
panic("unexpected reflect.Kind: " + rv.Kind().String())
}
}
// tomlArrayType returns the element type of a TOML array. The type returned
// may be nil if it cannot be determined (e.g., a nil slice or a zero length
// slize). This function may also panic if it finds a type that cannot be
// expressed in TOML (such as nil elements, heterogeneous arrays or directly
// nested arrays of tables).
func tomlArrayType(rv reflect.Value) tomlType {
if isNil(rv) || !rv.IsValid() || rv.Len() == 0 {
return nil
}
firstType := tomlTypeOfGo(rv.Index(0))
if firstType == nil {
encPanic(errArrayNilElement)
}
rvlen := rv.Len()
for i := 1; i < rvlen; i++ {
elem := rv.Index(i)
switch elemType := tomlTypeOfGo(elem); {
case elemType == nil:
encPanic(errArrayNilElement)
case !typeEqual(firstType, elemType):
encPanic(errArrayMixedElementTypes)
}
}
// If we have a nested array, then we must make sure that the nested
// array contains ONLY primitives.
// This checks arbitrarily nested arrays.
if typeEqual(firstType, tomlArray) || typeEqual(firstType, tomlArrayHash) {
nest := tomlArrayType(eindirect(rv.Index(0)))
if typeEqual(nest, tomlHash) || typeEqual(nest, tomlArrayHash) {
encPanic(errArrayNoTable)
}
}
return firstType
}
func (enc *Encoder) newline() {
if enc.hasWritten {
enc.wf("\n")
}
}
func (enc *Encoder) keyEqElement(key Key, val reflect.Value) {
if len(key) == 0 {
encPanic(errNoKey)
}
panicIfInvalidKey(key, false)
enc.wf("%s%s = ", enc.indentStr(key), key[len(key)-1])
enc.eElement(val)
enc.newline()
}
func (enc *Encoder) wf(format string, v ...interface{}) {
if _, err := fmt.Fprintf(enc.w, format, v...); err != nil {
encPanic(err)
}
enc.hasWritten = true
}
func (enc *Encoder) indentStr(key Key) string {
return strings.Repeat(enc.Indent, len(key)-1)
}
func encPanic(err error) {
panic(tomlEncodeError{err})
}
func eindirect(v reflect.Value) reflect.Value {
switch v.Kind() {
case reflect.Ptr, reflect.Interface:
return eindirect(v.Elem())
default:
return v
}
}
func isNil(rv reflect.Value) bool {
switch rv.Kind() {
case reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice:
return rv.IsNil()
default:
return false
}
}
func panicIfInvalidKey(key Key, hash bool) {
if hash {
for _, k := range key {
if !isValidTableName(k) {
encPanic(e("Key '%s' is not a valid table name. Table names "+
"cannot contain '[', ']' or '.'.", key.String()))
}
}
} else {
if !isValidKeyName(key[len(key)-1]) {
encPanic(e("Key '%s' is not a name. Key names "+
"cannot contain whitespace.", key.String()))
}
}
}
func isValidTableName(s string) bool {
if len(s) == 0 {
return false
}
for _, r := range s {
if r == '[' || r == ']' || r == '.' {
return false
}
}
return true
}
func isValidKeyName(s string) bool {
if len(s) == 0 {
return false
}
for _, r := range s {
if unicode.IsSpace(r) {
return false
}
}
return true
}

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@ -0,0 +1,506 @@
package toml
import (
"bytes"
"fmt"
"log"
"net"
"testing"
"time"
)
func TestEncodeRoundTrip(t *testing.T) {
type Config struct {
Age int
Cats []string
Pi float64
Perfection []int
DOB time.Time
Ipaddress net.IP
}
var inputs = Config{
13,
[]string{"one", "two", "three"},
3.145,
[]int{11, 2, 3, 4},
time.Now(),
net.ParseIP("192.168.59.254"),
}
var firstBuffer bytes.Buffer
e := NewEncoder(&firstBuffer)
err := e.Encode(inputs)
if err != nil {
t.Fatal(err)
}
var outputs Config
if _, err := Decode(firstBuffer.String(), &outputs); err != nil {
log.Printf("Could not decode:\n-----\n%s\n-----\n",
firstBuffer.String())
t.Fatal(err)
}
// could test each value individually, but I'm lazy
var secondBuffer bytes.Buffer
e2 := NewEncoder(&secondBuffer)
err = e2.Encode(outputs)
if err != nil {
t.Fatal(err)
}
if firstBuffer.String() != secondBuffer.String() {
t.Error(
firstBuffer.String(),
"\n\n is not identical to\n\n",
secondBuffer.String())
}
}
// XXX(burntsushi)
// I think these tests probably should be removed. They are good, but they
// ought to be obsolete by toml-test.
func TestEncode(t *testing.T) {
type Embedded struct {
Int int `toml:"_int"`
}
type NonStruct int
date := time.Date(2014, 5, 11, 20, 30, 40, 0, time.FixedZone("IST", 3600))
dateStr := "2014-05-11T19:30:40Z"
tests := map[string]struct {
input interface{}
wantOutput string
wantError error
}{
"bool field": {
input: struct {
BoolTrue bool
BoolFalse bool
}{true, false},
wantOutput: "BoolTrue = true\nBoolFalse = false\n",
},
"int fields": {
input: struct {
Int int
Int8 int8
Int16 int16
Int32 int32
Int64 int64
}{1, 2, 3, 4, 5},
wantOutput: "Int = 1\nInt8 = 2\nInt16 = 3\nInt32 = 4\nInt64 = 5\n",
},
"uint fields": {
input: struct {
Uint uint
Uint8 uint8
Uint16 uint16
Uint32 uint32
Uint64 uint64
}{1, 2, 3, 4, 5},
wantOutput: "Uint = 1\nUint8 = 2\nUint16 = 3\nUint32 = 4" +
"\nUint64 = 5\n",
},
"float fields": {
input: struct {
Float32 float32
Float64 float64
}{1.5, 2.5},
wantOutput: "Float32 = 1.5\nFloat64 = 2.5\n",
},
"string field": {
input: struct{ String string }{"foo"},
wantOutput: "String = \"foo\"\n",
},
"string field and unexported field": {
input: struct {
String string
unexported int
}{"foo", 0},
wantOutput: "String = \"foo\"\n",
},
"datetime field in UTC": {
input: struct{ Date time.Time }{date},
wantOutput: fmt.Sprintf("Date = %s\n", dateStr),
},
"datetime field as primitive": {
// Using a map here to fail if isStructOrMap() returns true for
// time.Time.
input: map[string]interface{}{
"Date": date,
"Int": 1,
},
wantOutput: fmt.Sprintf("Date = %s\nInt = 1\n", dateStr),
},
"array fields": {
input: struct {
IntArray0 [0]int
IntArray3 [3]int
}{[0]int{}, [3]int{1, 2, 3}},
wantOutput: "IntArray0 = []\nIntArray3 = [1, 2, 3]\n",
},
"slice fields": {
input: struct{ IntSliceNil, IntSlice0, IntSlice3 []int }{
nil, []int{}, []int{1, 2, 3},
},
wantOutput: "IntSlice0 = []\nIntSlice3 = [1, 2, 3]\n",
},
"datetime slices": {
input: struct{ DatetimeSlice []time.Time }{
[]time.Time{date, date},
},
wantOutput: fmt.Sprintf("DatetimeSlice = [%s, %s]\n",
dateStr, dateStr),
},
"nested arrays and slices": {
input: struct {
SliceOfArrays [][2]int
ArrayOfSlices [2][]int
SliceOfArraysOfSlices [][2][]int
ArrayOfSlicesOfArrays [2][][2]int
SliceOfMixedArrays [][2]interface{}
ArrayOfMixedSlices [2][]interface{}
}{
[][2]int{{1, 2}, {3, 4}},
[2][]int{{1, 2}, {3, 4}},
[][2][]int{
{
{1, 2}, {3, 4},
},
{
{5, 6}, {7, 8},
},
},
[2][][2]int{
{
{1, 2}, {3, 4},
},
{
{5, 6}, {7, 8},
},
},
[][2]interface{}{
{1, 2}, {"a", "b"},
},
[2][]interface{}{
{1, 2}, {"a", "b"},
},
},
wantOutput: `SliceOfArrays = [[1, 2], [3, 4]]
ArrayOfSlices = [[1, 2], [3, 4]]
SliceOfArraysOfSlices = [[[1, 2], [3, 4]], [[5, 6], [7, 8]]]
ArrayOfSlicesOfArrays = [[[1, 2], [3, 4]], [[5, 6], [7, 8]]]
SliceOfMixedArrays = [[1, 2], ["a", "b"]]
ArrayOfMixedSlices = [[1, 2], ["a", "b"]]
`,
},
"empty slice": {
input: struct{ Empty []interface{} }{[]interface{}{}},
wantOutput: "Empty = []\n",
},
"(error) slice with element type mismatch (string and integer)": {
input: struct{ Mixed []interface{} }{[]interface{}{1, "a"}},
wantError: errArrayMixedElementTypes,
},
"(error) slice with element type mismatch (integer and float)": {
input: struct{ Mixed []interface{} }{[]interface{}{1, 2.5}},
wantError: errArrayMixedElementTypes,
},
"slice with elems of differing Go types, same TOML types": {
input: struct {
MixedInts []interface{}
MixedFloats []interface{}
}{
[]interface{}{
int(1), int8(2), int16(3), int32(4), int64(5),
uint(1), uint8(2), uint16(3), uint32(4), uint64(5),
},
[]interface{}{float32(1.5), float64(2.5)},
},
wantOutput: "MixedInts = [1, 2, 3, 4, 5, 1, 2, 3, 4, 5]\n" +
"MixedFloats = [1.5, 2.5]\n",
},
"(error) slice w/ element type mismatch (one is nested array)": {
input: struct{ Mixed []interface{} }{
[]interface{}{1, []interface{}{2}},
},
wantError: errArrayMixedElementTypes,
},
"(error) slice with 1 nil element": {
input: struct{ NilElement1 []interface{} }{[]interface{}{nil}},
wantError: errArrayNilElement,
},
"(error) slice with 1 nil element (and other non-nil elements)": {
input: struct{ NilElement []interface{} }{
[]interface{}{1, nil},
},
wantError: errArrayNilElement,
},
"simple map": {
input: map[string]int{"a": 1, "b": 2},
wantOutput: "a = 1\nb = 2\n",
},
"map with interface{} value type": {
input: map[string]interface{}{"a": 1, "b": "c"},
wantOutput: "a = 1\nb = \"c\"\n",
},
"map with interface{} value type, some of which are structs": {
input: map[string]interface{}{
"a": struct{ Int int }{2},
"b": 1,
},
wantOutput: "b = 1\n\n[a]\n Int = 2\n",
},
"nested map": {
input: map[string]map[string]int{
"a": {"b": 1},
"c": {"d": 2},
},
wantOutput: "[a]\n b = 1\n\n[c]\n d = 2\n",
},
"nested struct": {
input: struct{ Struct struct{ Int int } }{
struct{ Int int }{1},
},
wantOutput: "[Struct]\n Int = 1\n",
},
"nested struct and non-struct field": {
input: struct {
Struct struct{ Int int }
Bool bool
}{struct{ Int int }{1}, true},
wantOutput: "Bool = true\n\n[Struct]\n Int = 1\n",
},
"2 nested structs": {
input: struct{ Struct1, Struct2 struct{ Int int } }{
struct{ Int int }{1}, struct{ Int int }{2},
},
wantOutput: "[Struct1]\n Int = 1\n\n[Struct2]\n Int = 2\n",
},
"deeply nested structs": {
input: struct {
Struct1, Struct2 struct{ Struct3 *struct{ Int int } }
}{
struct{ Struct3 *struct{ Int int } }{&struct{ Int int }{1}},
struct{ Struct3 *struct{ Int int } }{nil},
},
wantOutput: "[Struct1]\n [Struct1.Struct3]\n Int = 1" +
"\n\n[Struct2]\n",
},
"nested struct with nil struct elem": {
input: struct {
Struct struct{ Inner *struct{ Int int } }
}{
struct{ Inner *struct{ Int int } }{nil},
},
wantOutput: "[Struct]\n",
},
"nested struct with no fields": {
input: struct {
Struct struct{ Inner struct{} }
}{
struct{ Inner struct{} }{struct{}{}},
},
wantOutput: "[Struct]\n [Struct.Inner]\n",
},
"struct with tags": {
input: struct {
Struct struct {
Int int `toml:"_int"`
} `toml:"_struct"`
Bool bool `toml:"_bool"`
}{
struct {
Int int `toml:"_int"`
}{1}, true,
},
wantOutput: "_bool = true\n\n[_struct]\n _int = 1\n",
},
"embedded struct": {
input: struct{ Embedded }{Embedded{1}},
wantOutput: "_int = 1\n",
},
"embedded *struct": {
input: struct{ *Embedded }{&Embedded{1}},
wantOutput: "_int = 1\n",
},
"nested embedded struct": {
input: struct {
Struct struct{ Embedded } `toml:"_struct"`
}{struct{ Embedded }{Embedded{1}}},
wantOutput: "[_struct]\n _int = 1\n",
},
"nested embedded *struct": {
input: struct {
Struct struct{ *Embedded } `toml:"_struct"`
}{struct{ *Embedded }{&Embedded{1}}},
wantOutput: "[_struct]\n _int = 1\n",
},
"array of tables": {
input: struct {
Structs []*struct{ Int int } `toml:"struct"`
}{
[]*struct{ Int int }{{1}, {3}},
},
wantOutput: "[[struct]]\n Int = 1\n\n[[struct]]\n Int = 3\n",
},
"array of tables order": {
input: map[string]interface{}{
"map": map[string]interface{}{
"zero": 5,
"arr": []map[string]int{
map[string]int{
"friend": 5,
},
},
},
},
wantOutput: "[map]\n zero = 5\n\n [[map.arr]]\n friend = 5\n",
},
"(error) top-level slice": {
input: []struct{ Int int }{{1}, {2}, {3}},
wantError: errNoKey,
},
"(error) slice of slice": {
input: struct {
Slices [][]struct{ Int int }
}{
[][]struct{ Int int }{{{1}}, {{2}}, {{3}}},
},
wantError: errArrayNoTable,
},
"(error) map no string key": {
input: map[int]string{1: ""},
wantError: errNonString,
},
"(error) anonymous non-struct": {
input: struct{ NonStruct }{5},
wantError: errAnonNonStruct,
},
"(error) empty key name": {
input: map[string]int{"": 1},
wantError: errAnything,
},
"(error) empty map name": {
input: map[string]interface{}{
"": map[string]int{"v": 1},
},
wantError: errAnything,
},
}
for label, test := range tests {
encodeExpected(t, label, test.input, test.wantOutput, test.wantError)
}
}
func TestEncodeNestedTableArrays(t *testing.T) {
type song struct {
Name string `toml:"name"`
}
type album struct {
Name string `toml:"name"`
Songs []song `toml:"songs"`
}
type springsteen struct {
Albums []album `toml:"albums"`
}
value := springsteen{
[]album{
{"Born to Run",
[]song{{"Jungleland"}, {"Meeting Across the River"}}},
{"Born in the USA",
[]song{{"Glory Days"}, {"Dancing in the Dark"}}},
},
}
expected := `[[albums]]
name = "Born to Run"
[[albums.songs]]
name = "Jungleland"
[[albums.songs]]
name = "Meeting Across the River"
[[albums]]
name = "Born in the USA"
[[albums.songs]]
name = "Glory Days"
[[albums.songs]]
name = "Dancing in the Dark"
`
encodeExpected(t, "nested table arrays", value, expected, nil)
}
func TestEncodeArrayHashWithNormalHashOrder(t *testing.T) {
type Alpha struct {
V int
}
type Beta struct {
V int
}
type Conf struct {
V int
A Alpha
B []Beta
}
val := Conf{
V: 1,
A: Alpha{2},
B: []Beta{{3}},
}
expected := "V = 1\n\n[A]\n V = 2\n\n[[B]]\n V = 3\n"
encodeExpected(t, "array hash with normal hash order", val, expected, nil)
}
func encodeExpected(
t *testing.T, label string, val interface{}, wantStr string, wantErr error,
) {
var buf bytes.Buffer
enc := NewEncoder(&buf)
err := enc.Encode(val)
if err != wantErr {
if wantErr != nil {
if wantErr == errAnything && err != nil {
return
}
t.Errorf("%s: want Encode error %v, got %v", label, wantErr, err)
} else {
t.Errorf("%s: Encode failed: %s", label, err)
}
}
if err != nil {
return
}
if got := buf.String(); wantStr != got {
t.Errorf("%s: want\n-----\n%q\n-----\nbut got\n-----\n%q\n-----\n",
label, wantStr, got)
}
}
func ExampleEncoder_Encode() {
date, _ := time.Parse(time.RFC822, "14 Mar 10 18:00 UTC")
var config = map[string]interface{}{
"date": date,
"counts": []int{1, 1, 2, 3, 5, 8},
"hash": map[string]string{
"key1": "val1",
"key2": "val2",
},
}
buf := new(bytes.Buffer)
if err := NewEncoder(buf).Encode(config); err != nil {
log.Fatal(err)
}
fmt.Println(buf.String())
// Output:
// counts = [1, 1, 2, 3, 5, 8]
// date = 2010-03-14T18:00:00Z
//
// [hash]
// key1 = "val1"
// key2 = "val2"
}

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@ -0,0 +1,19 @@
// +build go1.2
package toml
// In order to support Go 1.1, we define our own TextMarshaler and
// TextUnmarshaler types. For Go 1.2+, we just alias them with the
// standard library interfaces.
import (
"encoding"
)
// TextMarshaler is a synonym for encoding.TextMarshaler. It is defined here
// so that Go 1.1 can be supported.
type TextMarshaler encoding.TextMarshaler
// TextUnmarshaler is a synonym for encoding.TextUnmarshaler. It is defined here
// so that Go 1.1 can be supported.
type TextUnmarshaler encoding.TextUnmarshaler

View file

@ -0,0 +1,18 @@
// +build !go1.2
package toml
// These interfaces were introduced in Go 1.2, so we add them manually when
// compiling for Go 1.1.
// TextMarshaler is a synonym for encoding.TextMarshaler. It is defined here
// so that Go 1.1 can be supported.
type TextMarshaler interface {
MarshalText() (text []byte, err error)
}
// TextUnmarshaler is a synonym for encoding.TextUnmarshaler. It is defined here
// so that Go 1.1 can be supported.
type TextUnmarshaler interface {
UnmarshalText(text []byte) error
}

725
Godeps/_workspace/src/github.com/BurntSushi/toml/lex.go generated vendored Normal file
View file

@ -0,0 +1,725 @@
package toml
import (
"fmt"
"unicode/utf8"
)
type itemType int
const (
itemError itemType = iota
itemNIL // used in the parser to indicate no type
itemEOF
itemText
itemString
itemBool
itemInteger
itemFloat
itemDatetime
itemArray // the start of an array
itemArrayEnd
itemTableStart
itemTableEnd
itemArrayTableStart
itemArrayTableEnd
itemKeyStart
itemCommentStart
)
const (
eof = 0
tableStart = '['
tableEnd = ']'
arrayTableStart = '['
arrayTableEnd = ']'
tableSep = '.'
keySep = '='
arrayStart = '['
arrayEnd = ']'
arrayValTerm = ','
commentStart = '#'
stringStart = '"'
stringEnd = '"'
)
type stateFn func(lx *lexer) stateFn
type lexer struct {
input string
start int
pos int
width int
line int
state stateFn
items chan item
// A stack of state functions used to maintain context.
// The idea is to reuse parts of the state machine in various places.
// For example, values can appear at the top level or within arbitrarily
// nested arrays. The last state on the stack is used after a value has
// been lexed. Similarly for comments.
stack []stateFn
}
type item struct {
typ itemType
val string
line int
}
func (lx *lexer) nextItem() item {
for {
select {
case item := <-lx.items:
return item
default:
lx.state = lx.state(lx)
}
}
}
func lex(input string) *lexer {
lx := &lexer{
input: input + "\n",
state: lexTop,
line: 1,
items: make(chan item, 10),
stack: make([]stateFn, 0, 10),
}
return lx
}
func (lx *lexer) push(state stateFn) {
lx.stack = append(lx.stack, state)
}
func (lx *lexer) pop() stateFn {
if len(lx.stack) == 0 {
return lx.errorf("BUG in lexer: no states to pop.")
}
last := lx.stack[len(lx.stack)-1]
lx.stack = lx.stack[0 : len(lx.stack)-1]
return last
}
func (lx *lexer) current() string {
return lx.input[lx.start:lx.pos]
}
func (lx *lexer) emit(typ itemType) {
lx.items <- item{typ, lx.current(), lx.line}
lx.start = lx.pos
}
func (lx *lexer) next() (r rune) {
if lx.pos >= len(lx.input) {
lx.width = 0
return eof
}
if lx.input[lx.pos] == '\n' {
lx.line++
}
r, lx.width = utf8.DecodeRuneInString(lx.input[lx.pos:])
lx.pos += lx.width
return r
}
// ignore skips over the pending input before this point.
func (lx *lexer) ignore() {
lx.start = lx.pos
}
// backup steps back one rune. Can be called only once per call of next.
func (lx *lexer) backup() {
lx.pos -= lx.width
if lx.pos < len(lx.input) && lx.input[lx.pos] == '\n' {
lx.line--
}
}
// accept consumes the next rune if it's equal to `valid`.
func (lx *lexer) accept(valid rune) bool {
if lx.next() == valid {
return true
}
lx.backup()
return false
}
// peek returns but does not consume the next rune in the input.
func (lx *lexer) peek() rune {
r := lx.next()
lx.backup()
return r
}
// errorf stops all lexing by emitting an error and returning `nil`.
// Note that any value that is a character is escaped if it's a special
// character (new lines, tabs, etc.).
func (lx *lexer) errorf(format string, values ...interface{}) stateFn {
lx.items <- item{
itemError,
fmt.Sprintf(format, values...),
lx.line,
}
return nil
}
// lexTop consumes elements at the top level of TOML data.
func lexTop(lx *lexer) stateFn {
r := lx.next()
if isWhitespace(r) || isNL(r) {
return lexSkip(lx, lexTop)
}
switch r {
case commentStart:
lx.push(lexTop)
return lexCommentStart
case tableStart:
return lexTableStart
case eof:
if lx.pos > lx.start {
return lx.errorf("Unexpected EOF.")
}
lx.emit(itemEOF)
return nil
}
// At this point, the only valid item can be a key, so we back up
// and let the key lexer do the rest.
lx.backup()
lx.push(lexTopEnd)
return lexKeyStart
}
// lexTopEnd is entered whenever a top-level item has been consumed. (A value
// or a table.) It must see only whitespace, and will turn back to lexTop
// upon a new line. If it sees EOF, it will quit the lexer successfully.
func lexTopEnd(lx *lexer) stateFn {
r := lx.next()
switch {
case r == commentStart:
// a comment will read to a new line for us.
lx.push(lexTop)
return lexCommentStart
case isWhitespace(r):
return lexTopEnd
case isNL(r):
lx.ignore()
return lexTop
case r == eof:
lx.ignore()
return lexTop
}
return lx.errorf("Expected a top-level item to end with a new line, "+
"comment or EOF, but got %q instead.", r)
}
// lexTable lexes the beginning of a table. Namely, it makes sure that
// it starts with a character other than '.' and ']'.
// It assumes that '[' has already been consumed.
// It also handles the case that this is an item in an array of tables.
// e.g., '[[name]]'.
func lexTableStart(lx *lexer) stateFn {
if lx.peek() == arrayTableStart {
lx.next()
lx.emit(itemArrayTableStart)
lx.push(lexArrayTableEnd)
} else {
lx.emit(itemTableStart)
lx.push(lexTableEnd)
}
return lexTableNameStart
}
func lexTableEnd(lx *lexer) stateFn {
lx.emit(itemTableEnd)
return lexTopEnd
}
func lexArrayTableEnd(lx *lexer) stateFn {
if r := lx.next(); r != arrayTableEnd {
return lx.errorf("Expected end of table array name delimiter %q, "+
"but got %q instead.", arrayTableEnd, r)
}
lx.emit(itemArrayTableEnd)
return lexTopEnd
}
func lexTableNameStart(lx *lexer) stateFn {
switch lx.next() {
case tableEnd:
return lx.errorf("Unexpected end of table. (Tables cannot " +
"be empty.)")
case tableSep:
return lx.errorf("Unexpected table separator. (Tables cannot " +
"be empty.)")
}
return lexTableName
}
// lexTableName lexes the name of a table. It assumes that at least one
// valid character for the table has already been read.
func lexTableName(lx *lexer) stateFn {
switch lx.peek() {
case tableStart:
return lx.errorf("Table names cannot contain %q or %q.",
tableStart, tableEnd)
case tableEnd:
lx.emit(itemText)
lx.next()
return lx.pop()
case tableSep:
lx.emit(itemText)
lx.next()
lx.ignore()
return lexTableNameStart
}
lx.next()
return lexTableName
}
// lexKeyStart consumes a key name up until the first non-whitespace character.
// lexKeyStart will ignore whitespace.
func lexKeyStart(lx *lexer) stateFn {
r := lx.peek()
switch {
case r == keySep:
return lx.errorf("Unexpected key separator %q.", keySep)
case isWhitespace(r) || isNL(r):
lx.next()
return lexSkip(lx, lexKeyStart)
}
lx.ignore()
lx.emit(itemKeyStart)
lx.next()
return lexKey
}
// lexKey consumes the text of a key. Assumes that the first character (which
// is not whitespace) has already been consumed.
func lexKey(lx *lexer) stateFn {
r := lx.peek()
// XXX: Possible divergence from spec?
// "Keys start with the first non-whitespace character and end with the
// last non-whitespace character before the equals sign."
// Note here that whitespace is either a tab or a space.
// But we'll call it quits if we see a new line too.
if isWhitespace(r) || isNL(r) {
lx.emit(itemText)
return lexKeyEnd
}
// Let's also call it quits if we see an equals sign.
if r == keySep {
lx.emit(itemText)
return lexKeyEnd
}
lx.next()
return lexKey
}
// lexKeyEnd consumes the end of a key (up to the key separator).
// Assumes that the first whitespace character after a key (or the '='
// separator) has NOT been consumed.
func lexKeyEnd(lx *lexer) stateFn {
r := lx.next()
switch {
case isWhitespace(r) || isNL(r):
return lexSkip(lx, lexKeyEnd)
case r == keySep:
return lexSkip(lx, lexValue)
}
return lx.errorf("Expected key separator %q, but got %q instead.",
keySep, r)
}
// lexValue starts the consumption of a value anywhere a value is expected.
// lexValue will ignore whitespace.
// After a value is lexed, the last state on the next is popped and returned.
func lexValue(lx *lexer) stateFn {
// We allow whitespace to precede a value, but NOT new lines.
// In array syntax, the array states are responsible for ignoring new lines.
r := lx.next()
if isWhitespace(r) {
return lexSkip(lx, lexValue)
}
switch {
case r == arrayStart:
lx.ignore()
lx.emit(itemArray)
return lexArrayValue
case r == stringStart:
lx.ignore() // ignore the '"'
return lexString
case r == 't':
return lexTrue
case r == 'f':
return lexFalse
case r == '-':
return lexNumberStart
case isDigit(r):
lx.backup() // avoid an extra state and use the same as above
return lexNumberOrDateStart
case r == '.': // special error case, be kind to users
return lx.errorf("Floats must start with a digit, not '.'.")
}
return lx.errorf("Expected value but found %q instead.", r)
}
// lexArrayValue consumes one value in an array. It assumes that '[' or ','
// have already been consumed. All whitespace and new lines are ignored.
func lexArrayValue(lx *lexer) stateFn {
r := lx.next()
switch {
case isWhitespace(r) || isNL(r):
return lexSkip(lx, lexArrayValue)
case r == commentStart:
lx.push(lexArrayValue)
return lexCommentStart
case r == arrayValTerm:
return lx.errorf("Unexpected array value terminator %q.",
arrayValTerm)
case r == arrayEnd:
return lexArrayEnd
}
lx.backup()
lx.push(lexArrayValueEnd)
return lexValue
}
// lexArrayValueEnd consumes the cruft between values of an array. Namely,
// it ignores whitespace and expects either a ',' or a ']'.
func lexArrayValueEnd(lx *lexer) stateFn {
r := lx.next()
switch {
case isWhitespace(r) || isNL(r):
return lexSkip(lx, lexArrayValueEnd)
case r == commentStart:
lx.push(lexArrayValueEnd)
return lexCommentStart
case r == arrayValTerm:
lx.ignore()
return lexArrayValue // move on to the next value
case r == arrayEnd:
return lexArrayEnd
}
return lx.errorf("Expected an array value terminator %q or an array "+
"terminator %q, but got %q instead.", arrayValTerm, arrayEnd, r)
}
// lexArrayEnd finishes the lexing of an array. It assumes that a ']' has
// just been consumed.
func lexArrayEnd(lx *lexer) stateFn {
lx.ignore()
lx.emit(itemArrayEnd)
return lx.pop()
}
// lexString consumes the inner contents of a string. It assumes that the
// beginning '"' has already been consumed and ignored.
func lexString(lx *lexer) stateFn {
r := lx.next()
switch {
case isNL(r):
return lx.errorf("Strings cannot contain new lines.")
case r == '\\':
return lexStringEscape
case r == stringEnd:
lx.backup()
lx.emit(itemString)
lx.next()
lx.ignore()
return lx.pop()
}
return lexString
}
// lexStringEscape consumes an escaped character. It assumes that the preceding
// '\\' has already been consumed.
func lexStringEscape(lx *lexer) stateFn {
r := lx.next()
switch r {
case 'b':
fallthrough
case 't':
fallthrough
case 'n':
fallthrough
case 'f':
fallthrough
case 'r':
fallthrough
case '"':
fallthrough
case '/':
fallthrough
case '\\':
return lexString
case 'u':
return lexStringUnicode
}
return lx.errorf("Invalid escape character %q. Only the following "+
"escape characters are allowed: "+
"\\b, \\t, \\n, \\f, \\r, \\\", \\/, \\\\, and \\uXXXX.", r)
}
// lexStringBinary consumes two hexadecimal digits following '\x'. It assumes
// that the '\x' has already been consumed.
func lexStringUnicode(lx *lexer) stateFn {
var r rune
for i := 0; i < 4; i++ {
r = lx.next()
if !isHexadecimal(r) {
return lx.errorf("Expected four hexadecimal digits after '\\x', "+
"but got '%s' instead.", lx.current())
}
}
return lexString
}
// lexNumberOrDateStart consumes either a (positive) integer, float or datetime.
// It assumes that NO negative sign has been consumed.
func lexNumberOrDateStart(lx *lexer) stateFn {
r := lx.next()
if !isDigit(r) {
if r == '.' {
return lx.errorf("Floats must start with a digit, not '.'.")
} else {
return lx.errorf("Expected a digit but got %q.", r)
}
}
return lexNumberOrDate
}
// lexNumberOrDate consumes either a (positive) integer, float or datetime.
func lexNumberOrDate(lx *lexer) stateFn {
r := lx.next()
switch {
case r == '-':
if lx.pos-lx.start != 5 {
return lx.errorf("All ISO8601 dates must be in full Zulu form.")
}
return lexDateAfterYear
case isDigit(r):
return lexNumberOrDate
case r == '.':
return lexFloatStart
}
lx.backup()
lx.emit(itemInteger)
return lx.pop()
}
// lexDateAfterYear consumes a full Zulu Datetime in ISO8601 format.
// It assumes that "YYYY-" has already been consumed.
func lexDateAfterYear(lx *lexer) stateFn {
formats := []rune{
// digits are '0'.
// everything else is direct equality.
'0', '0', '-', '0', '0',
'T',
'0', '0', ':', '0', '0', ':', '0', '0',
'Z',
}
for _, f := range formats {
r := lx.next()
if f == '0' {
if !isDigit(r) {
return lx.errorf("Expected digit in ISO8601 datetime, "+
"but found %q instead.", r)
}
} else if f != r {
return lx.errorf("Expected %q in ISO8601 datetime, "+
"but found %q instead.", f, r)
}
}
lx.emit(itemDatetime)
return lx.pop()
}
// lexNumberStart consumes either an integer or a float. It assumes that a
// negative sign has already been read, but that *no* digits have been consumed.
// lexNumberStart will move to the appropriate integer or float states.
func lexNumberStart(lx *lexer) stateFn {
// we MUST see a digit. Even floats have to start with a digit.
r := lx.next()
if !isDigit(r) {
if r == '.' {
return lx.errorf("Floats must start with a digit, not '.'.")
} else {
return lx.errorf("Expected a digit but got %q.", r)
}
}
return lexNumber
}
// lexNumber consumes an integer or a float after seeing the first digit.
func lexNumber(lx *lexer) stateFn {
r := lx.next()
switch {
case isDigit(r):
return lexNumber
case r == '.':
return lexFloatStart
}
lx.backup()
lx.emit(itemInteger)
return lx.pop()
}
// lexFloatStart starts the consumption of digits of a float after a '.'.
// Namely, at least one digit is required.
func lexFloatStart(lx *lexer) stateFn {
r := lx.next()
if !isDigit(r) {
return lx.errorf("Floats must have a digit after the '.', but got "+
"%q instead.", r)
}
return lexFloat
}
// lexFloat consumes the digits of a float after a '.'.
// Assumes that one digit has been consumed after a '.' already.
func lexFloat(lx *lexer) stateFn {
r := lx.next()
if isDigit(r) {
return lexFloat
}
lx.backup()
lx.emit(itemFloat)
return lx.pop()
}
// lexConst consumes the s[1:] in s. It assumes that s[0] has already been
// consumed.
func lexConst(lx *lexer, s string) stateFn {
for i := range s[1:] {
if r := lx.next(); r != rune(s[i+1]) {
return lx.errorf("Expected %q, but found %q instead.", s[:i+1],
s[:i]+string(r))
}
}
return nil
}
// lexTrue consumes the "rue" in "true". It assumes that 't' has already
// been consumed.
func lexTrue(lx *lexer) stateFn {
if fn := lexConst(lx, "true"); fn != nil {
return fn
}
lx.emit(itemBool)
return lx.pop()
}
// lexFalse consumes the "alse" in "false". It assumes that 'f' has already
// been consumed.
func lexFalse(lx *lexer) stateFn {
if fn := lexConst(lx, "false"); fn != nil {
return fn
}
lx.emit(itemBool)
return lx.pop()
}
// lexCommentStart begins the lexing of a comment. It will emit
// itemCommentStart and consume no characters, passing control to lexComment.
func lexCommentStart(lx *lexer) stateFn {
lx.ignore()
lx.emit(itemCommentStart)
return lexComment
}
// lexComment lexes an entire comment. It assumes that '#' has been consumed.
// It will consume *up to* the first new line character, and pass control
// back to the last state on the stack.
func lexComment(lx *lexer) stateFn {
r := lx.peek()
if isNL(r) || r == eof {
lx.emit(itemText)
return lx.pop()
}
lx.next()
return lexComment
}
// lexSkip ignores all slurped input and moves on to the next state.
func lexSkip(lx *lexer, nextState stateFn) stateFn {
return func(lx *lexer) stateFn {
lx.ignore()
return nextState
}
}
// isWhitespace returns true if `r` is a whitespace character according
// to the spec.
func isWhitespace(r rune) bool {
return r == '\t' || r == ' '
}
func isNL(r rune) bool {
return r == '\n' || r == '\r'
}
func isDigit(r rune) bool {
return r >= '0' && r <= '9'
}
func isHexadecimal(r rune) bool {
return (r >= '0' && r <= '9') ||
(r >= 'a' && r <= 'f') ||
(r >= 'A' && r <= 'F')
}
func (itype itemType) String() string {
switch itype {
case itemError:
return "Error"
case itemNIL:
return "NIL"
case itemEOF:
return "EOF"
case itemText:
return "Text"
case itemString:
return "String"
case itemBool:
return "Bool"
case itemInteger:
return "Integer"
case itemFloat:
return "Float"
case itemDatetime:
return "DateTime"
case itemTableStart:
return "TableStart"
case itemTableEnd:
return "TableEnd"
case itemKeyStart:
return "KeyStart"
case itemArray:
return "Array"
case itemArrayEnd:
return "ArrayEnd"
case itemCommentStart:
return "CommentStart"
}
panic(fmt.Sprintf("BUG: Unknown type '%d'.", int(itype)))
}
func (item item) String() string {
return fmt.Sprintf("(%s, %s)", item.typ.String(), item.val)
}

View file

@ -0,0 +1,417 @@
package toml
import (
"fmt"
"log"
"strconv"
"strings"
"time"
"unicode/utf8"
)
type parser struct {
mapping map[string]interface{}
types map[string]tomlType
lx *lexer
// A list of keys in the order that they appear in the TOML data.
ordered []Key
// the full key for the current hash in scope
context Key
// the base key name for everything except hashes
currentKey string
// rough approximation of line number
approxLine int
// A map of 'key.group.names' to whether they were created implicitly.
implicits map[string]bool
}
type parseError string
func (pe parseError) Error() string {
return string(pe)
}
func parse(data string) (p *parser, err error) {
defer func() {
if r := recover(); r != nil {
var ok bool
if err, ok = r.(parseError); ok {
return
}
panic(r)
}
}()
p = &parser{
mapping: make(map[string]interface{}),
types: make(map[string]tomlType),
lx: lex(data),
ordered: make([]Key, 0),
implicits: make(map[string]bool),
}
for {
item := p.next()
if item.typ == itemEOF {
break
}
p.topLevel(item)
}
return p, nil
}
func (p *parser) panicf(format string, v ...interface{}) {
msg := fmt.Sprintf("Near line %d, key '%s': %s",
p.approxLine, p.current(), fmt.Sprintf(format, v...))
panic(parseError(msg))
}
func (p *parser) next() item {
it := p.lx.nextItem()
if it.typ == itemError {
p.panicf("Near line %d: %s", it.line, it.val)
}
return it
}
func (p *parser) bug(format string, v ...interface{}) {
log.Fatalf("BUG: %s\n\n", fmt.Sprintf(format, v...))
}
func (p *parser) expect(typ itemType) item {
it := p.next()
p.assertEqual(typ, it.typ)
return it
}
func (p *parser) assertEqual(expected, got itemType) {
if expected != got {
p.bug("Expected '%s' but got '%s'.", expected, got)
}
}
func (p *parser) topLevel(item item) {
switch item.typ {
case itemCommentStart:
p.approxLine = item.line
p.expect(itemText)
case itemTableStart:
kg := p.expect(itemText)
p.approxLine = kg.line
key := make(Key, 0)
for ; kg.typ == itemText; kg = p.next() {
key = append(key, kg.val)
}
p.assertEqual(itemTableEnd, kg.typ)
p.establishContext(key, false)
p.setType("", tomlHash)
p.ordered = append(p.ordered, key)
case itemArrayTableStart:
kg := p.expect(itemText)
p.approxLine = kg.line
key := make(Key, 0)
for ; kg.typ == itemText; kg = p.next() {
key = append(key, kg.val)
}
p.assertEqual(itemArrayTableEnd, kg.typ)
p.establishContext(key, true)
p.setType("", tomlArrayHash)
p.ordered = append(p.ordered, key)
case itemKeyStart:
kname := p.expect(itemText)
p.currentKey = kname.val
p.approxLine = kname.line
val, typ := p.value(p.next())
p.setValue(p.currentKey, val)
p.setType(p.currentKey, typ)
p.ordered = append(p.ordered, p.context.add(p.currentKey))
p.currentKey = ""
default:
p.bug("Unexpected type at top level: %s", item.typ)
}
}
// value translates an expected value from the lexer into a Go value wrapped
// as an empty interface.
func (p *parser) value(it item) (interface{}, tomlType) {
switch it.typ {
case itemString:
return p.replaceUnicode(replaceEscapes(it.val)), p.typeOfPrimitive(it)
case itemBool:
switch it.val {
case "true":
return true, p.typeOfPrimitive(it)
case "false":
return false, p.typeOfPrimitive(it)
}
p.bug("Expected boolean value, but got '%s'.", it.val)
case itemInteger:
num, err := strconv.ParseInt(it.val, 10, 64)
if err != nil {
// See comment below for floats describing why we make a
// distinction between a bug and a user error.
if e, ok := err.(*strconv.NumError); ok &&
e.Err == strconv.ErrRange {
p.panicf("Integer '%s' is out of the range of 64-bit "+
"signed integers.", it.val)
} else {
p.bug("Expected integer value, but got '%s'.", it.val)
}
}
return num, p.typeOfPrimitive(it)
case itemFloat:
num, err := strconv.ParseFloat(it.val, 64)
if err != nil {
// Distinguish float values. Normally, it'd be a bug if the lexer
// provides an invalid float, but it's possible that the float is
// out of range of valid values (which the lexer cannot determine).
// So mark the former as a bug but the latter as a legitimate user
// error.
//
// This is also true for integers.
if e, ok := err.(*strconv.NumError); ok &&
e.Err == strconv.ErrRange {
p.panicf("Float '%s' is out of the range of 64-bit "+
"IEEE-754 floating-point numbers.", it.val)
} else {
p.bug("Expected float value, but got '%s'.", it.val)
}
}
return num, p.typeOfPrimitive(it)
case itemDatetime:
t, err := time.Parse("2006-01-02T15:04:05Z", it.val)
if err != nil {
p.bug("Expected Zulu formatted DateTime, but got '%s'.", it.val)
}
return t, p.typeOfPrimitive(it)
case itemArray:
array := make([]interface{}, 0)
types := make([]tomlType, 0)
for it = p.next(); it.typ != itemArrayEnd; it = p.next() {
if it.typ == itemCommentStart {
p.expect(itemText)
continue
}
val, typ := p.value(it)
array = append(array, val)
types = append(types, typ)
}
return array, p.typeOfArray(types)
}
p.bug("Unexpected value type: %s", it.typ)
panic("unreachable")
}
// establishContext sets the current context of the parser,
// where the context is either a hash or an array of hashes. Which one is
// set depends on the value of the `array` parameter.
//
// Establishing the context also makes sure that the key isn't a duplicate, and
// will create implicit hashes automatically.
func (p *parser) establishContext(key Key, array bool) {
var ok bool
// Always start at the top level and drill down for our context.
hashContext := p.mapping
keyContext := make(Key, 0)
// We only need implicit hashes for key[0:-1]
for _, k := range key[0 : len(key)-1] {
_, ok = hashContext[k]
keyContext = append(keyContext, k)
// No key? Make an implicit hash and move on.
if !ok {
p.addImplicit(keyContext)
hashContext[k] = make(map[string]interface{})
}
// If the hash context is actually an array of tables, then set
// the hash context to the last element in that array.
//
// Otherwise, it better be a table, since this MUST be a key group (by
// virtue of it not being the last element in a key).
switch t := hashContext[k].(type) {
case []map[string]interface{}:
hashContext = t[len(t)-1]
case map[string]interface{}:
hashContext = t
default:
p.panicf("Key '%s' was already created as a hash.", keyContext)
}
}
p.context = keyContext
if array {
// If this is the first element for this array, then allocate a new
// list of tables for it.
k := key[len(key)-1]
if _, ok := hashContext[k]; !ok {
hashContext[k] = make([]map[string]interface{}, 0, 5)
}
// Add a new table. But make sure the key hasn't already been used
// for something else.
if hash, ok := hashContext[k].([]map[string]interface{}); ok {
hashContext[k] = append(hash, make(map[string]interface{}))
} else {
p.panicf("Key '%s' was already created and cannot be used as "+
"an array.", keyContext)
}
} else {
p.setValue(key[len(key)-1], make(map[string]interface{}))
}
p.context = append(p.context, key[len(key)-1])
}
// setValue sets the given key to the given value in the current context.
// It will make sure that the key hasn't already been defined, account for
// implicit key groups.
func (p *parser) setValue(key string, value interface{}) {
var tmpHash interface{}
var ok bool
hash := p.mapping
keyContext := make(Key, 0)
for _, k := range p.context {
keyContext = append(keyContext, k)
if tmpHash, ok = hash[k]; !ok {
p.bug("Context for key '%s' has not been established.", keyContext)
}
switch t := tmpHash.(type) {
case []map[string]interface{}:
// The context is a table of hashes. Pick the most recent table
// defined as the current hash.
hash = t[len(t)-1]
case map[string]interface{}:
hash = t
default:
p.bug("Expected hash to have type 'map[string]interface{}', but "+
"it has '%T' instead.", tmpHash)
}
}
keyContext = append(keyContext, key)
if _, ok := hash[key]; ok {
// Typically, if the given key has already been set, then we have
// to raise an error since duplicate keys are disallowed. However,
// it's possible that a key was previously defined implicitly. In this
// case, it is allowed to be redefined concretely. (See the
// `tests/valid/implicit-and-explicit-after.toml` test in `toml-test`.)
//
// But we have to make sure to stop marking it as an implicit. (So that
// another redefinition provokes an error.)
//
// Note that since it has already been defined (as a hash), we don't
// want to overwrite it. So our business is done.
if p.isImplicit(keyContext) {
p.removeImplicit(keyContext)
return
}
// Otherwise, we have a concrete key trying to override a previous
// key, which is *always* wrong.
p.panicf("Key '%s' has already been defined.", keyContext)
}
hash[key] = value
}
// setType sets the type of a particular value at a given key.
// It should be called immediately AFTER setValue.
//
// Note that if `key` is empty, then the type given will be applied to the
// current context (which is either a table or an array of tables).
func (p *parser) setType(key string, typ tomlType) {
keyContext := make(Key, 0, len(p.context)+1)
for _, k := range p.context {
keyContext = append(keyContext, k)
}
if len(key) > 0 { // allow type setting for hashes
keyContext = append(keyContext, key)
}
p.types[keyContext.String()] = typ
}
// addImplicit sets the given Key as having been created implicitly.
func (p *parser) addImplicit(key Key) {
p.implicits[key.String()] = true
}
// removeImplicit stops tagging the given key as having been implicitly created.
func (p *parser) removeImplicit(key Key) {
p.implicits[key.String()] = false
}
// isImplicit returns true if the key group pointed to by the key was created
// implicitly.
func (p *parser) isImplicit(key Key) bool {
return p.implicits[key.String()]
}
// current returns the full key name of the current context.
func (p *parser) current() string {
if len(p.currentKey) == 0 {
return p.context.String()
}
if len(p.context) == 0 {
return p.currentKey
}
return fmt.Sprintf("%s.%s", p.context, p.currentKey)
}
func replaceEscapes(s string) string {
return strings.NewReplacer(
"\\b", "\u0008",
"\\t", "\u0009",
"\\n", "\u000A",
"\\f", "\u000C",
"\\r", "\u000D",
"\\\"", "\u0022",
"\\/", "\u002F",
"\\\\", "\u005C",
).Replace(s)
}
func (p *parser) replaceUnicode(s string) string {
indexEsc := func() int {
return strings.Index(s, "\\u")
}
for i := indexEsc(); i != -1; i = indexEsc() {
asciiBytes := s[i+2 : i+6]
s = strings.Replace(s, s[i:i+6], p.asciiEscapeToUnicode(asciiBytes), -1)
}
return s
}
func (p *parser) asciiEscapeToUnicode(s string) string {
hex, err := strconv.ParseUint(strings.ToLower(s), 16, 32)
if err != nil {
p.bug("Could not parse '%s' as a hexadecimal number, but the "+
"lexer claims it's OK: %s", s, err)
}
// BUG(burntsushi)
// I honestly don't understand how this works. I can't seem
// to find a way to make this fail. I figured this would fail on invalid
// UTF-8 characters like U+DCFF, but it doesn't.
r := string(rune(hex))
if !utf8.ValidString(r) {
p.panicf("Escaped character '\\u%s' is not valid UTF-8.", s)
}
return string(r)
}

View file

@ -0,0 +1 @@
au BufWritePost *.go silent!make tags > /dev/null 2>&1

View file

@ -0,0 +1,85 @@
package toml
// tomlType represents any Go type that corresponds to a TOML type.
// While the first draft of the TOML spec has a simplistic type system that
// probably doesn't need this level of sophistication, we seem to be militating
// toward adding real composite types.
type tomlType interface {
typeString() string
}
// typeEqual accepts any two types and returns true if they are equal.
func typeEqual(t1, t2 tomlType) bool {
if t1 == nil || t2 == nil {
return false
}
return t1.typeString() == t2.typeString()
}
func typeIsHash(t tomlType) bool {
return typeEqual(t, tomlHash) || typeEqual(t, tomlArrayHash)
}
type tomlBaseType string
func (btype tomlBaseType) typeString() string {
return string(btype)
}
func (btype tomlBaseType) String() string {
return btype.typeString()
}
var (
tomlInteger tomlBaseType = "Integer"
tomlFloat tomlBaseType = "Float"
tomlDatetime tomlBaseType = "Datetime"
tomlString tomlBaseType = "String"
tomlBool tomlBaseType = "Bool"
tomlArray tomlBaseType = "Array"
tomlHash tomlBaseType = "Hash"
tomlArrayHash tomlBaseType = "ArrayHash"
)
// typeOfPrimitive returns a tomlType of any primitive value in TOML.
// Primitive values are: Integer, Float, Datetime, String and Bool.
//
// Passing a lexer item other than the following will cause a BUG message
// to occur: itemString, itemBool, itemInteger, itemFloat, itemDatetime.
func (p *parser) typeOfPrimitive(lexItem item) tomlType {
switch lexItem.typ {
case itemInteger:
return tomlInteger
case itemFloat:
return tomlFloat
case itemDatetime:
return tomlDatetime
case itemString:
return tomlString
case itemBool:
return tomlBool
}
p.bug("Cannot infer primitive type of lex item '%s'.", lexItem)
panic("unreachable")
}
// typeOfArray returns a tomlType for an array given a list of types of its
// values.
//
// In the current spec, if an array is homogeneous, then its type is always
// "Array". If the array is not homogeneous, an error is generated.
func (p *parser) typeOfArray(types []tomlType) tomlType {
// Empty arrays are cool.
if len(types) == 0 {
return tomlArray
}
theType := types[0]
for _, t := range types[1:] {
if !typeEqual(theType, t) {
p.panicf("Array contains values of type '%s' and '%s', but arrays "+
"must be homogeneous.", theType, t)
}
}
return tomlArray
}

View file

@ -0,0 +1,241 @@
package toml
// Struct field handling is adapted from code in encoding/json:
//
// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the Go distribution.
import (
"reflect"
"sort"
"sync"
)
// A field represents a single field found in a struct.
type field struct {
name string // the name of the field (`toml` tag included)
tag bool // whether field has a `toml` tag
index []int // represents the depth of an anonymous field
typ reflect.Type // the type of the field
}
// byName sorts field by name, breaking ties with depth,
// then breaking ties with "name came from toml tag", then
// breaking ties with index sequence.
type byName []field
func (x byName) Len() int { return len(x) }
func (x byName) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
func (x byName) Less(i, j int) bool {
if x[i].name != x[j].name {
return x[i].name < x[j].name
}
if len(x[i].index) != len(x[j].index) {
return len(x[i].index) < len(x[j].index)
}
if x[i].tag != x[j].tag {
return x[i].tag
}
return byIndex(x).Less(i, j)
}
// byIndex sorts field by index sequence.
type byIndex []field
func (x byIndex) Len() int { return len(x) }
func (x byIndex) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
func (x byIndex) Less(i, j int) bool {
for k, xik := range x[i].index {
if k >= len(x[j].index) {
return false
}
if xik != x[j].index[k] {
return xik < x[j].index[k]
}
}
return len(x[i].index) < len(x[j].index)
}
// typeFields returns a list of fields that TOML should recognize for the given
// type. The algorithm is breadth-first search over the set of structs to
// include - the top struct and then any reachable anonymous structs.
func typeFields(t reflect.Type) []field {
// Anonymous fields to explore at the current level and the next.
current := []field{}
next := []field{{typ: t}}
// Count of queued names for current level and the next.
count := map[reflect.Type]int{}
nextCount := map[reflect.Type]int{}
// Types already visited at an earlier level.
visited := map[reflect.Type]bool{}
// Fields found.
var fields []field
for len(next) > 0 {
current, next = next, current[:0]
count, nextCount = nextCount, map[reflect.Type]int{}
for _, f := range current {
if visited[f.typ] {
continue
}
visited[f.typ] = true
// Scan f.typ for fields to include.
for i := 0; i < f.typ.NumField(); i++ {
sf := f.typ.Field(i)
if sf.PkgPath != "" { // unexported
continue
}
name := sf.Tag.Get("toml")
if name == "-" {
continue
}
index := make([]int, len(f.index)+1)
copy(index, f.index)
index[len(f.index)] = i
ft := sf.Type
if ft.Name() == "" && ft.Kind() == reflect.Ptr {
// Follow pointer.
ft = ft.Elem()
}
// Record found field and index sequence.
if name != "" || !sf.Anonymous || ft.Kind() != reflect.Struct {
tagged := name != ""
if name == "" {
name = sf.Name
}
fields = append(fields, field{name, tagged, index, ft})
if count[f.typ] > 1 {
// If there were multiple instances, add a second,
// so that the annihilation code will see a duplicate.
// It only cares about the distinction between 1 or 2,
// so don't bother generating any more copies.
fields = append(fields, fields[len(fields)-1])
}
continue
}
// Record new anonymous struct to explore in next round.
nextCount[ft]++
if nextCount[ft] == 1 {
f := field{name: ft.Name(), index: index, typ: ft}
next = append(next, f)
}
}
}
}
sort.Sort(byName(fields))
// Delete all fields that are hidden by the Go rules for embedded fields,
// except that fields with TOML tags are promoted.
// The fields are sorted in primary order of name, secondary order
// of field index length. Loop over names; for each name, delete
// hidden fields by choosing the one dominant field that survives.
out := fields[:0]
for advance, i := 0, 0; i < len(fields); i += advance {
// One iteration per name.
// Find the sequence of fields with the name of this first field.
fi := fields[i]
name := fi.name
for advance = 1; i+advance < len(fields); advance++ {
fj := fields[i+advance]
if fj.name != name {
break
}
}
if advance == 1 { // Only one field with this name
out = append(out, fi)
continue
}
dominant, ok := dominantField(fields[i : i+advance])
if ok {
out = append(out, dominant)
}
}
fields = out
sort.Sort(byIndex(fields))
return fields
}
// dominantField looks through the fields, all of which are known to
// have the same name, to find the single field that dominates the
// others using Go's embedding rules, modified by the presence of
// TOML tags. If there are multiple top-level fields, the boolean
// will be false: This condition is an error in Go and we skip all
// the fields.
func dominantField(fields []field) (field, bool) {
// The fields are sorted in increasing index-length order. The winner
// must therefore be one with the shortest index length. Drop all
// longer entries, which is easy: just truncate the slice.
length := len(fields[0].index)
tagged := -1 // Index of first tagged field.
for i, f := range fields {
if len(f.index) > length {
fields = fields[:i]
break
}
if f.tag {
if tagged >= 0 {
// Multiple tagged fields at the same level: conflict.
// Return no field.
return field{}, false
}
tagged = i
}
}
if tagged >= 0 {
return fields[tagged], true
}
// All remaining fields have the same length. If there's more than one,
// we have a conflict (two fields named "X" at the same level) and we
// return no field.
if len(fields) > 1 {
return field{}, false
}
return fields[0], true
}
var fieldCache struct {
sync.RWMutex
m map[reflect.Type][]field
}
// cachedTypeFields is like typeFields but uses a cache to avoid repeated work.
func cachedTypeFields(t reflect.Type) []field {
fieldCache.RLock()
f := fieldCache.m[t]
fieldCache.RUnlock()
if f != nil {
return f
}
// Compute fields without lock.
// Might duplicate effort but won't hold other computations back.
f = typeFields(t)
if f == nil {
f = []field{}
}
fieldCache.Lock()
if fieldCache.m == nil {
fieldCache.m = map[reflect.Type][]field{}
}
fieldCache.m[t] = f
fieldCache.Unlock()
return f
}

View file

@ -0,0 +1,3 @@
TAGS
tags
.*.swp

13
Godeps/_workspace/src/github.com/BurntSushi/ty/COPYING generated vendored Normal file
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@ -0,0 +1,13 @@
DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
Version 2, December 2004
Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>
Everyone is permitted to copy and distribute verbatim or modified
copies of this license document, and changing it is allowed as long
as the name is changed.
DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. You just DO WHAT THE FUCK YOU WANT TO.

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all: install
install:
go install ./...
test: install
go test ./...
benchcmp: install
cd fun \
&& echo "Running reflection benchmarks..." \
&& go test -cpu 12 -run NONE -benchmem -bench . > reflect.bench \
&& echo "Running built in benchmarks..." \
&& go test -cpu 12 -run NONE -benchmem -bench . -builtin > builtin.bench \
&& benchcmp builtin.bench reflect.bench > ../perf/cmp.bench \
&& rm builtin.bench reflect.bench
fmt:
gofmt -w *.go */*.go
colcheck *.go */*.go
tags:
find ./ -name '*.go' -print0 | xargs -0 gotags > TAGS
push:
git push origin master
git push github master

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Package `ty` provides utilities for writing type parametric functions with run
time type safety.
This package contains two sub-packages `fun` and `data` which define some
potentially useful functions and abstractions using the type checker in
this package.
## Requirements
Go tip (or 1.1 when it's released) is required. This package will not work
with Go 1.0.x or earlier.
The very foundation of this package only recently became possible with the
addition of 3 new functions in the standard library `reflect` package:
SliceOf, MapOf and ChanOf. In particular, it provides the ability to
dynamically construct types at run time from component types.
Further extensions to this package can be made if similar functions are added
for structs and functions(?).
## Installation
```bash
go get github.com/BurntSushi/ty
go get github.com/BurntSushi/ty/fun
```
## Examples
Squaring each integer in a slice:
```go
square := func(x int) int { return x * x }
nums := []int{1, 2, 3, 4, 5}
squares := Map(square, nums).([]int)
```
Reversing any slice:
```go
slice := []string{"a", "b", "c"}
reversed := Reverse(slice).([]string)
```
Sorting any slice:
```go
// Sort a slice of structs with first class functions.
type Album struct {
Title string
Year int
}
albums := []Album{
{"Born to Run", 1975},
{"WIESS", 1973},
{"Darkness", 1978},
{"Greetings", 1973},
}
less := func(a, b Album) bool { return a.Year < b.Year },
sorted := QuickSort(less, albums).([]Album)
```
Parallel map:
```go
// Compute the prime factorization concurrently
// for every integer in [1000, 10000].
primeFactors := func(n int) []int { // compute prime factors }
factors := ParMap(primeFactors, Range(1000, 10001)).([]int)
```
Asynchronous channel without a fixed size buffer:
```go
s, r := AsyncChan(new(chan int))
send, recv := s.(chan<- int), r.(<-chan int)
// Send as much as you want.
for i := 0; i < 100; i++ {
s <- i
}
close(s)
for i := range recv {
// do something with `i`
}
```
Shuffle any slice in place:
```go
jumbleMe := []string{"The", "quick", "brown", "fox"}
Shuffle(jumbleMe)
```
Function memoization:
```go
// Memoizing a recursive function like `fibonacci`.
// Write it like normal:
var fib func(n int64) int64
fib = func(n int64) int64 {
switch n {
case 0:
return 0
case 1:
return 1
}
return fib(n - 1) + fib(n - 2)
}
// And wrap it with `Memo`.
fib = Memo(fib).(func(int64) int64)
// Will keep your CPU busy for a long time
// without memoization.
fmt.Println(fib(80))
```

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/*
Package data tumbles down the rabbit hole into parametric data types.
A parametric data type in this package is a data type that is parameterized by
one or more types discovered at run time. For example, an ordered map is
parameterized by two types: the type of its keys and the type of its values.
Implementation
While all parametric inputs and outputs of each function have a Go type of
`interface{}`, the underlying type is maintained via reflection. In particular,
any operation that interacts with a parametric data type does so via
reflection so that the type safety found in Go at compile time can be
recovered at run time.
For example, consider the case of an ordered map. One might define such a map
as a list of its keys in order and a map of `interface{}` to `interface{}`:
type OrdMap struct {
M map[interface{}]interface{}
Keys []interface{}
}
And one can interact with this map using standard built-in Go operations:
// Add a key
M["key"] = "value"
Keys = append(Keys, "key")
// Delete a key
delete(M, "key")
// Read a key
M["key"]
But there is no type safety with such a representation, even at run time:
// Both of these operations are legal with
// the aforementioned representation.
M["key"] = "value"
M[5] = true
Thus, the contribution of this library is to maintain type safety at run time
by guaranteeing that all operations are consistent with Go typing rules:
type OrdMap struct {
M reflect.Value
Keys reflect.Value
}
And one must interact with a map using `reflect`:
key, val := "key", "value"
rkey := reflect.ValueOf(key)
rval := reflect.ValueOf(val)
// Add a key
M.SetMapIndex(rkey, rval)
Keys = reflect.Append(Keys, rkey)
// Delete a key
M.SetMapIndex(rkey, reflect.Value{})
// Read a key
M.MapIndex(rkey)
Which guarantees, at run-time, that the following cannot happen:
key2, val2 := 5, true
rkey2 := reflect.ValueOf(key2)
rval2 := reflect.ValueOf(val2)
// One or the other operation will be disallowed,
// assuming `OrdMap` isn't instantiated with
// `interface{}` as the key and value type.
M.SetMapIndex(rkey, rval)
M.SetMapIndex(rkey2, rval2)
The result is much more painful library code but only slightly more painful
client code.
*/
package data

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package data
import (
"reflect"
"github.com/BurntSushi/ty"
)
// OrdMap has a parametric type `OrdMap<K, V>` where `K` is the type
// of the map's keys and `V` is the type of the map's values.
type OrdMap struct {
m reflect.Value
keys reflect.Value
ktype, vtype reflect.Type
}
// OrderedMap returns a new instance of OrdMap instantiated with the key
// and value types given. Namely, the types should be provided via nil
// pointers, e.g., to create a map from strings to integers:
//
// omap := OrderedMap(new(string), new(int))
//
// An ordered map maintains the insertion order of all keys in the map.
// Namely, `(*OrdMap).Keys()` returns a slice of keys in the order
// they were inserted. The order of a key can *only* be changed if it is
// deleted and added again.
//
// All of the operations on an ordered map have the same time complexity as
// the built-in `map`, except for `Delete` which is O(n) in the number of
// keys.
func OrderedMap(ktype, vtype interface{}) *OrdMap {
// A giant hack to get `Check` to do all the type construction work for us.
chk := ty.Check(
new(func(*ty.A, *ty.B) (ty.A, ty.B, map[ty.A]ty.B, []ty.A)),
ktype, vtype)
tkey, tval := chk.Returns[0], chk.Returns[1]
tmap, tkeys := chk.Returns[2], chk.Returns[3]
return &OrdMap{
m: reflect.MakeMap(tmap),
keys: reflect.MakeSlice(tkeys, 0, 10),
ktype: tkey,
vtype: tval,
}
}
// Exists has a parametric type:
//
// func (om *OrdMap<K, V>) Exists(key K) bool
//
// Exists returns true if `key` is in the map `om`.
func (om *OrdMap) Exists(key interface{}) bool {
rkey := ty.AssertType(key, om.ktype)
return om.exists(rkey)
}
func (om *OrdMap) exists(rkey reflect.Value) bool {
return om.m.MapIndex(rkey).IsValid()
}
// Put has a parametric type:
//
// func (om *OrdMap<K, V>) Put(key K, val V)
//
// Put adds or overwrites `key` into the map `om` with value `val`.
// If `key` already exists in the map, then its position in the ordering
// of the map is not changed.
func (om *OrdMap) Put(key, val interface{}) {
rkey := ty.AssertType(key, om.ktype)
rval := ty.AssertType(val, om.vtype)
if !om.exists(rkey) {
om.keys = reflect.Append(om.keys, rkey)
}
om.m.SetMapIndex(rkey, rval)
}
// Get has a parametric type:
//
// func (om *OrdMap<K, V>) Get(key K) V
//
// Get retrieves the value in the map `om` corresponding to `key`. If the
// value does not exist, then the zero value of type `V` is returned.
func (om *OrdMap) Get(key interface{}) interface{} {
rkey := ty.AssertType(key, om.ktype)
rval := om.m.MapIndex(rkey)
if !rval.IsValid() {
return om.zeroValue().Interface()
}
return rval.Interface()
}
// TryGet has a parametric type:
//
// func (om *OrdMap<K, V>) TryGet(key K) (V, bool)
//
// TryGet retrieves the value in the map `om` corresponding to `key` and
// reports whether the value exists in the map or not. If the value does
// not exist, then the zero value of `V` and `false` are returned.
func (om *OrdMap) TryGet(key interface{}) (interface{}, bool) {
rkey := ty.AssertType(key, om.ktype)
rval := om.m.MapIndex(rkey)
if !rval.IsValid() {
return om.zeroValue().Interface(), false
}
return rval.Interface(), true
}
// Delete has a parametric type:
//
// func (om *OrdMap<K, V>) Delete(key K)
//
// Delete removes `key` from the map `om`.
//
// N.B. Delete is O(n) in the number of keys.
func (om *OrdMap) Delete(key interface{}) {
rkey := ty.AssertType(key, om.ktype)
// Avoid doing work if we don't need to.
if !om.exists(rkey) {
return
}
keysLen := om.keys.Len()
for i := 0; i < keysLen; i++ {
if key == om.keys.Index(i).Interface() {
// om.keys = append(om.keys[:i], om.keys[i+1:]...)
om.keys = reflect.AppendSlice(
om.keys.Slice(0, i), om.keys.Slice(i+1, keysLen))
break
}
}
// Setting a key to a zero reflect.Value deletes the key from the map.
om.m.SetMapIndex(rkey, reflect.Value{})
}
// Keys has a parametric type:
//
// func (om *OrdMap<K, V>) Keys() []K
//
// Keys returns a list of keys in `om` in the order they were inserted.
//
// Behavior is undefined if the list is modified by the caller.
func (om *OrdMap) Keys() interface{} {
return om.keys.Interface()
}
// Values has a parametric type:
//
// func (om *OrdMap<K, V>) Values() []V
//
// Values returns a shallow copy of the values in `om` in the order that they
// were inserted.
func (om *OrdMap) Values() interface{} {
mlen := om.Len()
tvals := reflect.SliceOf(om.vtype)
rvals := reflect.MakeSlice(tvals, mlen, mlen)
for i := 0; i < mlen; i++ {
rvals.Index(i).Set(om.m.MapIndex(om.keys.Index(i)))
}
return rvals.Interface()
}
// Len has a parametric type:
//
// func (om *OrdMap<K, V>) Len() int
//
// Len returns the number of keys in the map `om`.
func (om *OrdMap) Len() int {
return om.m.Len()
}
func (om *OrdMap) zeroValue() reflect.Value {
return reflect.New(om.vtype).Elem()
}

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package data
import (
"fmt"
"reflect"
"testing"
)
var pf = fmt.Printf
func TestOrdMap(t *testing.T) {
omap := OrderedMap(new(string), new(int))
omap.Put("kaitlyn", 24)
omap.Put("andrew", 25)
omap.Put("lauren", 20)
omap.Put("jen", 24)
omap.Put("brennan", 25)
omap.Delete("kaitlyn")
assertDeep(t, omap.Keys(), []string{"andrew", "lauren", "jen", "brennan"})
assertDeep(t, omap.Values(), []int{25, 20, 24, 25})
}
func ExampleOrderedMap() {
omap := OrderedMap(new(string), new([]string))
omap.Put("Bruce Springsteen",
[]string{"Thunder Road", "Born to Run", "This Hard Land"})
omap.Put("J. Geils Band",
[]string{"Musta Got Lost", "Freeze Frame", "Southside Shuffle"})
omap.Put("Bob Seger",
[]string{"Against the Wind", "Roll Me Away", "Night Moves"})
for _, key := range omap.Keys().([]string) {
fmt.Println(key)
}
omap.Delete("J. Geils Band")
fmt.Println("\nDeleted 'J. Geils Band'...\n")
for _, key := range omap.Keys().([]string) {
fmt.Printf("%s: %v\n", key, omap.Get(key))
}
// Output:
// Bruce Springsteen
// J. Geils Band
// Bob Seger
//
// Deleted 'J. Geils Band'...
//
// Bruce Springsteen: [Thunder Road Born to Run This Hard Land]
// Bob Seger: [Against the Wind Roll Me Away Night Moves]
}
func assertDeep(t *testing.T, v1, v2 interface{}) {
if !reflect.DeepEqual(v1, v2) {
t.Fatalf("%v != %v", v1, v2)
}
}

22
Godeps/_workspace/src/github.com/BurntSushi/ty/doc.go generated vendored Normal file
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/*
Package ty provides utilities for writing type parametric functions with run
time type safety.
This package contains two sub-packages `fun` and `data` which define some
potentially useful functions and abstractions using the type checker in
this package.
Requirements
Go tip (or 1.1 when it's released) is required. This package will not work
with Go 1.0.x or earlier.
The very foundation of this package only recently became possible with the
addition of 3 new functions in the standard library `reflect` package:
SliceOf, MapOf and ChanOf. In particular, it provides the ability to
dynamically construct types at run time from component types.
Further extensions to this package can be made if similar functions are added
for structs and functions(?).
*/
package ty

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package fun
import (
"reflect"
"github.com/BurntSushi/ty"
)
// AsyncChan has a parametric type:
//
// func AsyncChan(chan A) (send chan<- A, recv <-chan A)
//
// AsyncChan provides a channel abstraction without a fixed size buffer.
// The input should be a pointer to a channel that has a type without a
// direction, e.g., `new(chan int)`. Two new channels are returned: `send` and
// `recv`. The caller must send data on the `send` channel and receive data on
// the `recv` channel.
//
// Implementation is inspired by Kyle Lemons' work:
// https://github.com/kylelemons/iq/blob/master/iq_slice.go
func AsyncChan(baseChan interface{}) (send, recv interface{}) {
chk := ty.Check(
new(func(*chan ty.A) (chan ty.A, chan ty.A)),
baseChan)
// We don't care about the baseChan---it is only used to construct
// the return types.
tsend, trecv := chk.Returns[0], chk.Returns[1]
buf := make([]reflect.Value, 0, 10)
rsend := reflect.MakeChan(tsend, 0)
rrecv := reflect.MakeChan(trecv, 0)
go func() {
defer rrecv.Close()
BUFLOOP:
for {
if len(buf) == 0 {
rv, ok := rsend.Recv()
if !ok {
break BUFLOOP
}
buf = append(buf, rv)
}
cases := []reflect.SelectCase{
// case v, ok := <-send
{
Dir: reflect.SelectRecv,
Chan: rsend,
},
// case recv <- buf[0]
{
Dir: reflect.SelectSend,
Chan: rrecv,
Send: buf[0],
},
}
choice, rval, rok := reflect.Select(cases)
switch choice {
case 0:
// case v, ok := <-send
if !rok {
break BUFLOOP
}
buf = append(buf, rval)
case 1:
// case recv <- buf[0]
buf = buf[1:]
default:
panic("bug")
}
}
for _, rv := range buf {
rrecv.Send(rv)
}
}()
// Create the directional channel types.
tsDir := reflect.ChanOf(reflect.SendDir, tsend.Elem())
trDir := reflect.ChanOf(reflect.RecvDir, trecv.Elem())
return rsend.Convert(tsDir).Interface(), rrecv.Convert(trDir).Interface()
}

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package fun
import (
"testing"
)
func TestAsyncChan(t *testing.T) {
s, r := AsyncChan(new(chan int))
send, recv := s.(chan<- int), r.(<-chan int)
sending := randIntSlice(1000, 0)
for _, v := range sending {
send <- v
}
close(send)
received := make([]int, 0)
for v := range recv {
received = append(received, v)
}
assertDeep(t, sending, received)
}

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/*
Package fun provides type parametric utility functions for lists, sets,
channels and maps.
The central contribution of this package is a set of functions that operate
on values without depending on their types while maintaining type safety at
run time using the `reflect` package.
There are two primary concerns when deciding whether to use this package
or not: the loss of compile time type safety and performance. In particular,
with regard to performance, most functions here are much slower than their
built-in counter parts. However, there are a couple where the overhead of
reflection is relatively insignificant: AsyncChan and ParMap.
In terms of code structure and organization, the price is mostly paid inside
of the package due to the annoyances of operating with `reflect`. The caller
usually only has one obligation other than to provide values consistent with
the type of the function: type assert the result to the desired type.
When the caller provides values that are inconsistent with the parametric type
of the function, the function will panic with a `TypeError`. (Either because
the types cannot be unified or because they cannot be constructed due to
limitations of the `reflect` package. See the `github.com/BurntSushi/ty`
package for more details.)
Requirements
Go tip (or 1.1 when it's released) is required. This package will not work
with Go 1.0.x or earlier.
The very foundation of this package only recently became possible with the
addition of 3 new functions in the standard library `reflect` package:
SliceOf, MapOf and ChanOf. In particular, it provides the ability to
dynamically construct types at run time from component types.
Further extensions to this package can be made if similar functions are added
for structs and functions(?).
Examples
Squaring each integer in a slice:
square := func(x int) int { return x * x }
nums := []int{1, 2, 3, 4, 5}
squares := Map(square, nums).([]int)
Reversing any slice:
slice := []string{"a", "b", "c"}
reversed := Reverse(slice).([]string)
Sorting any slice:
// Sort a slice of structs with first class functions.
type Album struct {
Title string
Year int
}
albums := []Album{
{"Born to Run", 1975},
{"WIESS", 1973},
{"Darkness", 1978},
{"Greetings", 1973},
}
less := func(a, b Album) bool { return a.Year < b.Year },
sorted := QuickSort(less, albums).([]Album)
Parallel map:
// Compute the prime factorization concurrently
// for every integer in [1000, 10000].
primeFactors := func(n int) []int { // compute prime factors }
factors := ParMap(primeFactors, Range(1000, 10001)).([]int)
Asynchronous channel without a fixed size buffer:
s, r := AsyncChan(new(chan int))
send, recv := s.(chan<- int), r.(<-chan int)
// Send as much as you want.
for i := 0; i < 100; i++ {
s <- i
}
close(s)
for i := range recv {
// do something with `i`
}
Shuffle any slice in place:
jumbleMe := []string{"The", "quick", "brown", "fox"}
Shuffle(jumbleMe)
Function memoization:
// Memoizing a recursive function like `fibonacci`.
// Write it like normal:
var fib func(n int64) int64
fib = func(n int64) int64 {
switch n {
case 0:
return 0
case 1:
return 1
}
return fib(n - 1) + fib(n - 2)
}
// And wrap it with `Memo`.
fib = Memo(fib).(func(int64) int64)
// Will keep your CPU busy for a long time
// without memoization.
fmt.Println(fib(80))
*/
package fun

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package fun
import (
"flag"
"fmt"
"math/rand"
"reflect"
"testing"
"time"
)
var (
pf = fmt.Printf
rng *rand.Rand
flagBuiltin = false
)
func init() {
rng = rand.New(rand.NewSource(time.Now().UnixNano()))
flag.BoolVar(&flagBuiltin, "builtin", flagBuiltin,
"When set, benchmarks for non-type parametric functions are run.")
}
func assertDeep(t *testing.T, v1, v2 interface{}) {
if !reflect.DeepEqual(v1, v2) {
t.Fatalf("%v != %v", v1, v2)
}
}
func randIntSlice(size, max int) []int {
if max == 0 {
max = 1000000
}
slice := make([]int, size)
for i := 0; i < size; i++ {
slice[i] = rng.Intn(max)
}
return slice
}
func randInt64Slice(size, max int64) []int64 {
if max == 0 {
max = 1000000
}
slice := make([]int64, size)
for i := int64(0); i < size; i++ {
slice[i] = rng.Int63n(max)
}
return slice
}

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package fun
import (
"reflect"
"github.com/BurntSushi/ty"
)
// Memo has a parametric type:
//
// func Memo(f func(A) B) func(A) B
//
// Memo memoizes any function of a single argument that returns a single value.
// The type `A` must be a Go type for which the comparison operators `==` and
// `!=` are fully defined (this rules out functions, maps and slices).
func Memo(f interface{}) interface{} {
chk := ty.Check(
new(func(func(ty.A) ty.B)),
f)
vf := chk.Args[0]
saved := make(map[interface{}]reflect.Value)
memo := func(in []reflect.Value) []reflect.Value {
val := in[0].Interface()
ret, ok := saved[val]
if ok {
return []reflect.Value{ret}
}
ret = call1(vf, in[0])
saved[val] = ret
return []reflect.Value{ret}
}
return reflect.MakeFunc(vf.Type(), memo).Interface()
}

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package fun
import (
"fmt"
"testing"
)
// The benchmarks are the test. The memo version (w/ reflection or not) should
// always be faster than the non-memo version given big enough N.
func BenchmarkFibonacciMemo(b *testing.B) {
if flagBuiltin {
benchmarkFibonacciMemoBuiltin(b)
} else {
benchmarkFibonacciMemoReflect(b)
}
}
func benchmarkFibonacciMemoBuiltin(b *testing.B) {
for i := 0; i < b.N; i++ {
fibonacciMemoBuiltin(30)
}
}
func benchmarkFibonacciMemoReflect(b *testing.B) {
for i := 0; i < b.N; i++ {
fibonacciMemoReflect(30)
}
}
func BenchmarkFibonacciNoMemo(b *testing.B) {
for i := 0; i < b.N; i++ {
fibonacci(30)
}
}
func fibonacciMemoBuiltin(n int) int {
memo := func(f func(int) int) func(int) int {
saved := make(map[int]int)
return func(n int) int {
ret, ok := saved[n]
if ok {
return ret
}
ret = f(n)
saved[n] = ret
return ret
}
}
var fib func(n int) int
fib = memo(func(n int) int {
switch n {
case 0:
return 0
case 1:
return 1
}
return fib(n-1) + fib(n-2)
})
return fib(n)
}
func fibonacciMemoReflect(n int) int {
var fib func(n int) int
fib = Memo(func(n int) int {
switch n {
case 0:
return 0
case 1:
return 1
}
return fib(n-1) + fib(n-2)
}).(func(int) int)
return fib(n)
}
func fibonacci(n int) int {
switch n {
case 0:
return 0
case 1:
return 1
}
return fibonacci(n-1) + fibonacci(n-2)
}
func ExampleMemo() {
// Memoizing a recursive function like `fibonacci`.
// Write it like normal:
var fib func(n int64) int64
fib = func(n int64) int64 {
switch n {
case 0:
return 0
case 1:
return 1
}
return fib(n-1) + fib(n-2)
}
// And wrap it with `Memo`.
fib = Memo(fib).(func(int64) int64)
// Will keep your CPU busy for a long time
// without memoization.
fmt.Println(fib(80))
// Output:
// 23416728348467685
}

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package fun
import (
"reflect"
"runtime"
"sync"
"github.com/BurntSushi/ty"
)
// All has a parametric type:
//
// func All(p func(A) bool, xs []A) bool
//
// All returns `true` if and only if every element in `xs` satisfies `p`.
func All(f, xs interface{}) bool {
chk := ty.Check(
new(func(func(ty.A) bool, []ty.A) bool),
f, xs)
vf, vxs := chk.Args[0], chk.Args[1]
xsLen := vxs.Len()
for i := 0; i < xsLen; i++ {
if !call1(vf, vxs.Index(i)).Interface().(bool) {
return false
}
}
return true
}
// Exists has a parametric type:
//
// func Exists(p func(A) bool, xs []A) bool
//
// Exists returns `true` if and only if an element in `xs` satisfies `p`.
func Exists(f, xs interface{}) bool {
chk := ty.Check(
new(func(func(ty.A) bool, []ty.A) bool),
f, xs)
vf, vxs := chk.Args[0], chk.Args[1]
xsLen := vxs.Len()
for i := 0; i < xsLen; i++ {
if call1(vf, vxs.Index(i)).Interface().(bool) {
return true
}
}
return false
}
// In has a parametric type:
//
// func In(needle A, haystack []A) bool
//
// In returns `true` if and only if `v` can be found in `xs`. The equality test
// used is Go's standard `==` equality and NOT deep equality.
//
// Note that this requires that `A` be a type that can be meaningfully compared.
func In(needle, haystack interface{}) bool {
chk := ty.Check(
new(func(ty.A, []ty.A) bool),
needle, haystack)
vhaystack := chk.Args[1]
length := vhaystack.Len()
for i := 0; i < length; i++ {
if vhaystack.Index(i).Interface() == needle {
return true
}
}
return false
}
// Map has a parametric type:
//
// func Map(f func(A) B, xs []A) []B
//
// Map returns the list corresponding to the return value of applying
// `f` to each element in `xs`.
func Map(f, xs interface{}) interface{} {
chk := ty.Check(
new(func(func(ty.A) ty.B, []ty.A) []ty.B),
f, xs)
vf, vxs, tys := chk.Args[0], chk.Args[1], chk.Returns[0]
xsLen := vxs.Len()
vys := reflect.MakeSlice(tys, xsLen, xsLen)
for i := 0; i < xsLen; i++ {
vy := call1(vf, vxs.Index(i))
vys.Index(i).Set(vy)
}
return vys.Interface()
}
// Filter has a parametric type:
//
// func Filter(p func(A) bool, xs []A) []A
//
// Filter returns a new list only containing the elements of `xs` that satisfy
// the predicate `p`.
func Filter(p, xs interface{}) interface{} {
chk := ty.Check(
new(func(func(ty.A) bool, []ty.A) []ty.A),
p, xs)
vp, vxs, tys := chk.Args[0], chk.Args[1], chk.Returns[0]
xsLen := vxs.Len()
vys := reflect.MakeSlice(tys, 0, xsLen)
for i := 0; i < xsLen; i++ {
vx := vxs.Index(i)
if call1(vp, vx).Bool() {
vys = reflect.Append(vys, vx)
}
}
return vys.Interface()
}
// Foldl has a parametric type:
//
// func Foldl(f func(A, B) B, init B, xs []A) B
//
// Foldl reduces a list of A to a single element B using a left fold with
// an initial value `init`.
func Foldl(f, init, xs interface{}) interface{} {
chk := ty.Check(
new(func(func(ty.A, ty.B) ty.B, ty.B, []ty.A) ty.B),
f, init, xs)
vf, vinit, vxs, tb := chk.Args[0], chk.Args[1], chk.Args[2], chk.Returns[0]
xsLen := vxs.Len()
vb := zeroValue(tb)
vb.Set(vinit)
if xsLen == 0 {
return vb.Interface()
}
vb.Set(call1(vf, vxs.Index(0), vb))
for i := 1; i < xsLen; i++ {
vb.Set(call1(vf, vxs.Index(i), vb))
}
return vb.Interface()
}
// Foldr has a parametric type:
//
// func Foldr(f func(A, B) B, init B, xs []A) B
//
// Foldr reduces a list of A to a single element B using a right fold with
// an initial value `init`.
func Foldr(f, init, xs interface{}) interface{} {
chk := ty.Check(
new(func(func(ty.A, ty.B) ty.B, ty.B, []ty.A) ty.B),
f, init, xs)
vf, vinit, vxs, tb := chk.Args[0], chk.Args[1], chk.Args[2], chk.Returns[0]
xsLen := vxs.Len()
vb := zeroValue(tb)
vb.Set(vinit)
if xsLen == 0 {
return vb.Interface()
}
vb.Set(call1(vf, vxs.Index(xsLen-1), vb))
for i := xsLen - 2; i >= 0; i-- {
vb.Set(call1(vf, vxs.Index(i), vb))
}
return vb.Interface()
}
// Concat has a parametric type:
//
// func Concat(xs [][]A) []A
//
// Concat returns a new flattened list by appending all elements of `xs`.
func Concat(xs interface{}) interface{} {
chk := ty.Check(
new(func([][]ty.A) []ty.A),
xs)
vxs, tflat := chk.Args[0], chk.Returns[0]
xsLen := vxs.Len()
vflat := reflect.MakeSlice(tflat, 0, xsLen*3)
for i := 0; i < xsLen; i++ {
vflat = reflect.AppendSlice(vflat, vxs.Index(i))
}
return vflat.Interface()
}
// Reverse has a parametric type:
//
// func Reverse(xs []A) []A
//
// Reverse returns a new slice that is the reverse of `xs`.
func Reverse(xs interface{}) interface{} {
chk := ty.Check(
new(func([]ty.A) []ty.A),
xs)
vxs, tys := chk.Args[0], chk.Returns[0]
xsLen := vxs.Len()
vys := reflect.MakeSlice(tys, xsLen, xsLen)
for i := 0; i < xsLen; i++ {
vys.Index(i).Set(vxs.Index(xsLen - 1 - i))
}
return vys.Interface()
}
// Copy has a parametric type:
//
// func Copy(xs []A) []A
//
// Copy returns a copy of `xs` using Go's `copy` operation.
func Copy(xs interface{}) interface{} {
chk := ty.Check(
new(func([]ty.A) []ty.A),
xs)
vxs, tys := chk.Args[0], chk.Returns[0]
xsLen := vxs.Len()
vys := reflect.MakeSlice(tys, xsLen, xsLen)
reflect.Copy(vys, vxs)
return vys.Interface()
}
// ParMap has a parametric type:
//
// func ParMap(f func(A) B, xs []A) []B
//
// ParMap is just like Map, except it applies `f` to each element in `xs`
// concurrently using N worker goroutines (where N is the number of CPUs
// available reported by the Go runtime). If you want to control the number
// of goroutines spawned, use `ParMapN`.
//
// It is important that `f` not be a trivial operation, otherwise the overhead
// of executing it concurrently will result in worse performance than using
// a `Map`.
func ParMap(f, xs interface{}) interface{} {
n := runtime.NumCPU()
if n < 1 {
n = 1
}
return ParMapN(f, xs, n)
}
// ParMapN has a parametric type:
//
// func ParMapN(f func(A) B, xs []A, n int) []B
//
// ParMapN is just like Map, except it applies `f` to each element in `xs`
// concurrently using `n` worker goroutines.
//
// It is important that `f` not be a trivial operation, otherwise the overhead
// of executing it concurrently will result in worse performance than using
// a `Map`.
func ParMapN(f, xs interface{}, n int) interface{} {
chk := ty.Check(
new(func(func(ty.A) ty.B, []ty.A) []ty.B),
f, xs)
vf, vxs, tys := chk.Args[0], chk.Args[1], chk.Returns[0]
xsLen := vxs.Len()
ys := reflect.MakeSlice(tys, xsLen, xsLen)
if n < 1 {
n = 1
}
work := make(chan int, n)
wg := new(sync.WaitGroup)
for i := 0; i < n; i++ {
wg.Add(1)
go func() {
for j := range work {
// Good golly miss molly. Is `reflect.Value.Index`
// safe to access/set from multiple goroutines?
// XXX: If not, we'll need an extra wave of allocation to
// use real slices of `reflect.Value`.
ys.Index(j).Set(call1(vf, vxs.Index(j)))
}
wg.Done()
}()
}
for i := 0; i < xsLen; i++ {
work <- i
}
close(work)
wg.Wait()
return ys.Interface()
}
// Range generates a list of integers corresponding to every integer in
// the half-open interval [x, y).
//
// Range will panic if `end < start`.
func Range(start, end int) []int {
if end < start {
panic("range must have end greater than or equal to start")
}
r := make([]int, end-start)
for i := start; i < end; i++ {
r[i-start] = i
}
return r
}

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package fun
import (
"math"
"runtime"
"sync"
"testing"
)
func TestParMap(t *testing.T) {
square := func(x int) int { return x * x }
squares := ParMap(square, []int{1, 2, 3, 4, 5}).([]int)
assertDeep(t, squares, []int{1, 4, 9, 16, 25})
assertDeep(t, []int{}, ParMap(square, []int{}).([]int))
}
func BenchmarkParMapSquare(b *testing.B) {
if flagBuiltin {
benchmarkParMapSquareBuiltin(b)
} else {
benchmarkParMapSquareReflect(b)
}
}
func benchmarkParMapSquareReflect(b *testing.B) {
b.StopTimer()
square := func(a int64) int64 { return a * a }
list := randInt64Slice(1000, 1<<30)
b.StartTimer()
for i := 0; i < b.N; i++ {
_ = ParMap(square, list).([]int64)
}
}
func benchmarkParMapSquareBuiltin(b *testing.B) {
b.StopTimer()
square := func(a int64) int64 { return a * a }
list := randInt64Slice(1000, 1<<30)
b.StartTimer()
for i := 0; i < b.N; i++ {
_ = parMapInt64(square, list)
}
}
func BenchmarkParMapPrime(b *testing.B) {
if flagBuiltin {
benchmarkParMapPrimeBuiltin(b)
} else {
benchmarkParMapPrimeReflect(b)
}
}
func benchmarkParMapPrimeReflect(b *testing.B) {
b.StopTimer()
list := randInt64Slice(1000, 1<<30)
b.StartTimer()
for i := 0; i < b.N; i++ {
_ = ParMap(primeFactors, list).([][]int64)
}
}
func benchmarkParMapPrimeBuiltin(b *testing.B) {
b.StopTimer()
list := randInt64Slice(1000, 1<<30)
b.StartTimer()
for i := 0; i < b.N; i++ {
_ = parMapSliceInt64(primeFactors, list)
}
}
func primeFactors(n int64) []int64 {
if isPrime(n) {
return []int64{n}
}
bound := int64(math.Floor(math.Sqrt(float64(n))))
for i := int64(2); i <= bound; i++ {
if n%i == 0 {
return append(primeFactors(i), primeFactors(n/i)...)
}
}
panic("unreachable")
}
func isPrime(n int64) bool {
bound := int64(math.Floor(math.Sqrt(float64(n))))
for i := int64(2); i <= bound; i++ {
if n%i == 0 {
return false
}
}
return true
}
func parMapInt64(f func(n int64) int64, xs []int64) []int64 {
ys := make([]int64, len(xs), len(xs))
N := runtime.NumCPU()
if N < 1 {
N = 1
}
work := make(chan int, N)
wg := new(sync.WaitGroup)
for i := 0; i < N; i++ {
wg.Add(1)
go func() {
for j := range work {
ys[j] = f(xs[j])
}
wg.Done()
}()
}
for i := 0; i < len(xs); i++ {
work <- i
}
close(work)
wg.Wait()
return ys
}
func parMapSliceInt64(f func(n int64) []int64, xs []int64) [][]int64 {
ys := make([][]int64, len(xs), len(xs))
N := runtime.NumCPU()
if N < 1 {
N = 1
}
work := make(chan int, N)
wg := new(sync.WaitGroup)
for i := 0; i < N; i++ {
wg.Add(1)
go func() {
for j := range work {
ys[j] = f(xs[j])
}
wg.Done()
}()
}
for i := 0; i < len(xs); i++ {
work <- i
}
close(work)
wg.Wait()
return ys
}

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package fun
import (
"testing"
)
func TestMap(t *testing.T) {
square := func(x int) int { return x * x }
squares := Map(square, []int{1, 2, 3, 4, 5}).([]int)
assertDeep(t, squares, []int{1, 4, 9, 16, 25})
assertDeep(t, []int{}, Map(square, []int{}).([]int))
strlen := func(s string) int { return len(s) }
lens := Map(strlen, []string{"abc", "ab", "a"}).([]int)
assertDeep(t, lens, []int{3, 2, 1})
}
func TestFilter(t *testing.T) {
even := func(x int) bool { return x%2 == 0 }
evens := Filter(even, []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}).([]int)
assertDeep(t, evens, []int{2, 4, 6, 8, 10})
assertDeep(t, []int{}, Filter(even, []int{}).([]int))
}
func TestFoldl(t *testing.T) {
// Use an operation that isn't associative so that we know we've got
// the left/right folds done correctly.
reducer := func(a, b int) int { return b % a }
v := Foldl(reducer, 7, []int{4, 5, 6}).(int)
assertDeep(t, v, 3)
assertDeep(t, 0, Foldl(reducer, 0, []int{}).(int))
}
func TestFoldr(t *testing.T) {
// Use an operation that isn't associative so that we know we've got
// the left/right folds done correctly.
reducer := func(a, b int) int { return b % a }
v := Foldr(reducer, 7, []int{4, 5, 6}).(int)
assertDeep(t, v, 1)
assertDeep(t, 0, Foldr(reducer, 0, []int{}).(int))
}
func TestConcat(t *testing.T) {
toflat := [][]int{
{1, 2, 3},
{4, 5, 6},
{7, 8, 9},
}
flat := Concat(toflat).([]int)
assertDeep(t, flat, []int{1, 2, 3, 4, 5, 6, 7, 8, 9})
}
func TestReverse(t *testing.T) {
reversed := Reverse([]int{1, 2, 3, 4, 5}).([]int)
assertDeep(t, reversed, []int{5, 4, 3, 2, 1})
}
func TestCopy(t *testing.T) {
orig := []int{1, 2, 3, 4, 5}
copied := Copy(orig).([]int)
orig[1] = 999
assertDeep(t, copied, []int{1, 2, 3, 4, 5})
}
func TestPointers(t *testing.T) {
type temp struct {
val int
}
square := func(t *temp) *temp { return &temp{t.val * t.val} }
squares := Map(square, []*temp{
{1}, {2}, {3}, {4}, {5},
})
assertDeep(t, squares, []*temp{
{1}, {4}, {9}, {16}, {25},
})
}
func BenchmarkMapSquare(b *testing.B) {
if flagBuiltin {
benchmarkMapSquareBuiltin(b)
} else {
benchmarkMapSquareReflect(b)
}
}
func benchmarkMapSquareReflect(b *testing.B) {
b.StopTimer()
square := func(a int64) int64 { return a * a }
list := randInt64Slice(1000, 1<<30)
b.StartTimer()
for i := 0; i < b.N; i++ {
_ = Map(square, list).([]int64)
}
}
func benchmarkMapSquareBuiltin(b *testing.B) {
b.StopTimer()
square := func(a int64) int64 { return a * a }
list := randInt64Slice(1000, 1<<30)
b.StartTimer()
for i := 0; i < b.N; i++ {
ret := make([]int64, len(list))
for i := 0; i < len(list); i++ {
ret[i] = square(list[i])
}
}
}
func BenchmarkMapPrime(b *testing.B) {
if flagBuiltin {
benchmarkMapPrimeBuiltin(b)
} else {
benchmarkMapPrimeReflect(b)
}
}
func benchmarkMapPrimeReflect(b *testing.B) {
b.StopTimer()
list := randInt64Slice(1000, 1<<30)
b.StartTimer()
for i := 0; i < b.N; i++ {
_ = Map(primeFactors, list).([][]int64)
}
}
func benchmarkMapPrimeBuiltin(b *testing.B) {
b.StopTimer()
list := randInt64Slice(1000, 1<<30)
b.StartTimer()
for i := 0; i < b.N; i++ {
ret := make([][]int64, len(list))
for i := 0; i < len(list); i++ {
ret[i] = primeFactors(list[i])
}
}
}

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@ -0,0 +1,46 @@
package fun
import (
"reflect"
"github.com/BurntSushi/ty"
)
// Keys has a parametric type:
//
// func Keys(m map[A]B) []A
//
// Keys returns a list of the keys of `m` in an unspecified order.
func Keys(m interface{}) interface{} {
chk := ty.Check(
new(func(map[ty.A]ty.B) []ty.A),
m)
vm, tkeys := chk.Args[0], chk.Returns[0]
vkeys := reflect.MakeSlice(tkeys, vm.Len(), vm.Len())
for i, vkey := range vm.MapKeys() {
vkeys.Index(i).Set(vkey)
}
return vkeys.Interface()
}
// Values has a parametric type:
//
// func Values(m map[A]B) []B
//
// Values returns a list of the values of `m` in an unspecified order.
func Values(m interface{}) interface{} {
chk := ty.Check(
new(func(map[ty.A]ty.B) []ty.B),
m)
vm, tvals := chk.Args[0], chk.Returns[0]
vvals := reflect.MakeSlice(tvals, vm.Len(), vm.Len())
for i, vkey := range vm.MapKeys() {
vvals.Index(i).Set(vm.MapIndex(vkey))
}
return vvals.Interface()
}
// func MapMerge(m1, m2 interface{}) interface{} {
// }

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@ -0,0 +1,25 @@
package fun
import (
"testing"
)
func TestKeys(t *testing.T) {
m := map[string]int{
"c": 0, "b": 0, "a": 0,
}
keys := Keys(m).([]string)
scmp := func(a, b string) bool { return a < b }
assertDeep(t, []string{"a", "b", "c"}, QuickSort(scmp, keys))
}
func TestValues(t *testing.T) {
m := map[int]string{
1: "c", 2: "b", 3: "a",
}
vals := Values(m).([]string)
scmp := func(a, b string) bool { return a < b }
assertDeep(t, []string{"a", "b", "c"}, QuickSort(scmp, vals))
}

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@ -0,0 +1,94 @@
package fun
import (
"math/rand"
"reflect"
"time"
"github.com/BurntSushi/ty"
)
var randNumGen *rand.Rand
func init() {
randNumGen = rand.New(rand.NewSource(time.Now().UnixNano()))
}
// ShuffleGen has a parametric type:
//
// func ShuffleGen(xs []A, rng *rand.Rand)
//
// ShuffleGen shuffles `xs` in place using the given random number
// generator `rng`.
func ShuffleGen(xs interface{}, rng *rand.Rand) {
chk := ty.Check(
new(func([]ty.A, *rand.Rand)),
xs, rng)
vxs := chk.Args[0]
// Implements the Fisher-Yates shuffle: http://goo.gl/Hb9vg
xsLen := vxs.Len()
swapper := swapperOf(vxs.Type().Elem())
for i := xsLen - 1; i >= 1; i-- {
j := rng.Intn(i + 1)
swapper.swap(vxs.Index(i), vxs.Index(j))
}
}
// Shuffle has a parametric type:
//
// func Shuffle(xs []A)
//
// Shuffle shuffles `xs` in place using a default random number
// generator seeded once at program initialization.
func Shuffle(xs interface{}) {
ShuffleGen(xs, randNumGen)
}
// Sample has a parametric type:
//
// func Sample(population []A, n int) []A
//
// Sample returns a random sample of size `n` from a list
// `population` using a default random number generator seeded once at
// program initialization.
// All elements in `population` have an equal chance of being selected.
// If `n` is greater than the size of `population`, then `n` is set to
// the size of the population.
func Sample(population interface{}, n int) interface{} {
return SampleGen(population, n, randNumGen)
}
// SampleGen has a parametric type:
//
// func SampleGen(population []A, n int, rng *rand.Rand) []A
//
// SampleGen returns a random sample of size `n` from a list
// `population` using a given random number generator `rng`.
// All elements in `population` have an equal chance of being selected.
// If `n` is greater than the size of `population`, then `n` is set to
// the size of the population.
func SampleGen(population interface{}, n int, rng *rand.Rand) interface{} {
chk := ty.Check(
new(func([]ty.A, int, *rand.Rand) []ty.A),
population, n, rng)
rpop, tsamp := chk.Args[0], chk.Returns[0]
popLen := rpop.Len()
if n == 0 {
return reflect.MakeSlice(tsamp, 0, 0).Interface()
}
if n > popLen {
n = popLen
}
// TODO(burntsushi): Implement an algorithm that doesn't depend on
// the size of the population.
rsamp := reflect.MakeSlice(tsamp, n, n)
choices := rng.Perm(popLen)
for i := 0; i < n; i++ {
rsamp.Index(i).Set(rpop.Index(choices[i]))
}
return rsamp.Interface()
}

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@ -0,0 +1,100 @@
package fun
import (
"math/rand"
"testing"
)
func TestShuffle(t *testing.T) {
nums := Range(0, 100)
Shuffle(nums)
assertDeep(t, Set(nums), Set(Range(0, 100)))
}
func TestSample(t *testing.T) {
rng := rand.New(rand.NewSource(0))
nums := Range(0, 100)
sample := SampleGen(nums, 3, rng).([]int)
assertDeep(t, Set([]int{35, 40, 50}), Set(sample))
}
func BenchmarkShuffle(b *testing.B) {
if flagBuiltin {
benchmarkShuffleBuiltin(b)
} else {
benchmarkShuffleReflect(b)
}
}
func benchmarkShuffleBuiltin(b *testing.B) {
b.StopTimer()
list := randIntSlice(10000, 0)
b.StartTimer()
for i := 0; i < b.N; i++ {
shuffle(list)
}
}
func benchmarkShuffleReflect(b *testing.B) {
b.StopTimer()
list := randIntSlice(10000, 0)
b.StartTimer()
for i := 0; i < b.N; i++ {
Shuffle(list)
}
}
func shuffle(xs []int) {
for i := len(xs) - 1; i >= 1; i-- {
j := randNumGen.Intn(i + 1)
xs[i], xs[j] = xs[j], xs[i]
}
}
func BenchmarkSample(b *testing.B) {
if flagBuiltin {
benchmarkSampleBuiltin(b)
} else {
benchmarkSampleReflect(b)
}
}
func benchmarkSampleBuiltin(b *testing.B) {
b.StopTimer()
list := randIntSlice(10000, 0)
b.StartTimer()
for i := 0; i < b.N; i++ {
sample(list, 100)
}
}
func benchmarkSampleReflect(b *testing.B) {
b.StopTimer()
list := randIntSlice(10000, 0)
b.StartTimer()
for i := 0; i < b.N; i++ {
Sample(list, 100)
}
}
func sample(pop []int, n int) []int {
if n == 0 {
return []int{}
}
if n > len(pop) {
n = len(pop)
}
samp := make([]int, n, n)
choices := randNumGen.Perm(len(pop))
for i := 0; i < n; i++ {
samp[i] = pop[choices[i]]
}
return samp
}

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@ -0,0 +1,99 @@
package fun
import (
"reflect"
"github.com/BurntSushi/ty"
)
// Set has a parametric type:
//
// func Set(xs []A) map[A]bool
//
// Set creates a set from a list.
func Set(xs interface{}) interface{} {
chk := ty.Check(
new(func([]ty.A) map[ty.A]bool),
xs)
vxs, tset := chk.Args[0], chk.Returns[0]
vtrue := reflect.ValueOf(true)
vset := reflect.MakeMap(tset)
xsLen := vxs.Len()
for i := 0; i < xsLen; i++ {
vset.SetMapIndex(vxs.Index(i), vtrue)
}
return vset.Interface()
}
// Union has a parametric type:
//
// func Union(a map[A]bool, b map[A]bool) map[A]bool
//
// Union returns the union of two sets, where a set is represented as a
// `map[A]bool`. The sets `a` and `b` are not modified.
func Union(a, b interface{}) interface{} {
chk := ty.Check(
new(func(map[ty.A]bool, map[ty.A]bool) map[ty.A]bool),
a, b)
va, vb, tc := chk.Args[0], chk.Args[1], chk.Returns[0]
vtrue := reflect.ValueOf(true)
vc := reflect.MakeMap(tc)
for _, vkey := range va.MapKeys() {
vc.SetMapIndex(vkey, vtrue)
}
for _, vkey := range vb.MapKeys() {
vc.SetMapIndex(vkey, vtrue)
}
return vc.Interface()
}
// Intersection has a parametric type:
//
// func Intersection(a map[A]bool, b map[A]bool) map[A]bool
//
// Intersection returns the intersection of two sets, where a set is
// represented as a `map[A]bool`. The sets `a` and `b` are not modified.
func Intersection(a, b interface{}) interface{} {
chk := ty.Check(
new(func(map[ty.A]bool, map[ty.A]bool) map[ty.A]bool),
a, b)
va, vb, tc := chk.Args[0], chk.Args[1], chk.Returns[0]
vtrue := reflect.ValueOf(true)
vc := reflect.MakeMap(tc)
for _, vkey := range va.MapKeys() {
if vb.MapIndex(vkey).IsValid() {
vc.SetMapIndex(vkey, vtrue)
}
}
for _, vkey := range vb.MapKeys() {
if va.MapIndex(vkey).IsValid() {
vc.SetMapIndex(vkey, vtrue)
}
}
return vc.Interface()
}
// Difference has a parametric type:
//
// func Difference(a map[A]bool, b map[A]bool) map[A]bool
//
// Difference returns a set with all elements in `a` that are not in `b`.
// The sets `a` and `b` are not modified.
func Difference(a, b interface{}) interface{} {
chk := ty.Check(
new(func(map[ty.A]bool, map[ty.A]bool) map[ty.A]bool),
a, b)
va, vb, tc := chk.Args[0], chk.Args[1], chk.Returns[0]
vtrue := reflect.ValueOf(true)
vc := reflect.MakeMap(tc)
for _, vkey := range va.MapKeys() {
if !vb.MapIndex(vkey).IsValid() {
vc.SetMapIndex(vkey, vtrue)
}
}
return vc.Interface()
}

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package fun
import (
"testing"
)
func TestSet(t *testing.T) {
a := []string{"andrew", "plato", "andrew", "cauchy", "cauchy", "andrew"}
set := Set(a).(map[string]bool)
assertDeep(t, set, map[string]bool{
"andrew": true,
"plato": true,
"cauchy": true,
})
}
func TestUnion(t *testing.T) {
a := map[string]bool{
"springsteen": true,
"jgeils": true,
"seger": true,
"metallica": true,
}
b := map[string]bool{
"metallica": true,
"chesney": true,
"mcgraw": true,
"cash": true,
}
c := Union(a, b).(map[string]bool)
assertDeep(t, c, map[string]bool{
"springsteen": true,
"jgeils": true,
"seger": true,
"metallica": true,
"chesney": true,
"mcgraw": true,
"cash": true,
})
}
func TestIntersection(t *testing.T) {
a := map[string]bool{
"springsteen": true,
"jgeils": true,
"seger": true,
"metallica": true,
}
b := map[string]bool{
"metallica": true,
"chesney": true,
"mcgraw": true,
"cash": true,
}
c := Intersection(a, b).(map[string]bool)
assertDeep(t, c, map[string]bool{
"metallica": true,
})
}
func TestDifference(t *testing.T) {
a := map[string]bool{
"springsteen": true,
"jgeils": true,
"seger": true,
"metallica": true,
}
b := map[string]bool{
"metallica": true,
"chesney": true,
"mcgraw": true,
"cash": true,
}
c := Difference(a, b).(map[string]bool)
assertDeep(t, c, map[string]bool{
"springsteen": true,
"jgeils": true,
"seger": true,
})
}

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@ -0,0 +1,98 @@
package fun
import (
"reflect"
"sort"
"github.com/BurntSushi/ty"
)
// QuickSort has a parametric type:
//
// func QuickSort(less func(x1 A, x2 A) bool, []A) []A
//
// QuickSort applies the "quicksort" algorithm to return a new sorted list
// of `xs`, where `xs` is not modified.
//
// `less` should be a function that returns true if and only if `x1` is less
// than `x2`.
func QuickSort(less, xs interface{}) interface{} {
chk := ty.Check(
new(func(func(ty.A, ty.A) bool, []ty.A) []ty.A),
less, xs)
vless, vxs, tys := chk.Args[0], chk.Args[1], chk.Returns[0]
var qsort func(left, right int)
var partition func(left, right, pivot int) int
xsind := Range(0, vxs.Len())
qsort = func(left, right int) {
if left >= right {
return
}
pivot := (left + right) / 2
pivot = partition(left, right, pivot)
qsort(left, pivot-1)
qsort(pivot+1, right)
}
partition = func(left, right, pivot int) int {
vpivot := xsind[pivot]
xsind[pivot], xsind[right] = xsind[right], xsind[pivot]
ind := left
for i := left; i < right; i++ {
if call1(vless, vxs.Index(xsind[i]), vxs.Index(vpivot)).Bool() {
xsind[i], xsind[ind] = xsind[ind], xsind[i]
ind++
}
}
xsind[ind], xsind[right] = xsind[right], xsind[ind]
return ind
}
// Sort `xsind` in place.
qsort(0, len(xsind)-1)
vys := reflect.MakeSlice(tys, len(xsind), len(xsind))
for i, xsIndex := range xsind {
vys.Index(i).Set(vxs.Index(xsIndex))
}
return vys.Interface()
}
// Sort has a parametric type:
//
// func Sort(less func(x1 A, x2 A) bool, []A)
//
// Sort uses the standard library `sort` package to sort `xs` in place.
//
// `less` should be a function that returns true if and only if `x1` is less
// than `x2`.
func Sort(less, xs interface{}) {
chk := ty.Check(
new(func(func(ty.A, ty.A) bool, []ty.A)),
less, xs)
vless, vxs := chk.Args[0], chk.Args[1]
sort.Sort(&sortable{vless, vxs, swapperOf(vxs.Type().Elem())})
}
type sortable struct {
less reflect.Value
xs reflect.Value
swapper swapper
}
func (s *sortable) Less(i, j int) bool {
ith, jth := s.xs.Index(i), s.xs.Index(j)
return call1(s.less, ith, jth).Bool()
}
func (s *sortable) Swap(i, j int) {
s.swapper.swap(s.xs.Index(i), s.xs.Index(j))
}
func (s *sortable) Len() int {
return s.xs.Len()
}

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@ -0,0 +1,120 @@
package fun
import (
"sort"
"testing"
)
func TestSort(t *testing.T) {
tosort := []int{10, 3, 5, 1, 15, 6}
Sort(func(a, b int) bool { return b < a }, tosort)
assertDeep(t, tosort, []int{15, 10, 6, 5, 3, 1})
}
func TestQuickSort(t *testing.T) {
tosort := []int{10, 3, 5, 1, 15, 6}
sorted := QuickSort(
func(a, b int) bool {
return b < a
}, tosort).([]int)
assertDeep(t, sorted, []int{15, 10, 6, 5, 3, 1})
}
func BenchmarkSort(b *testing.B) {
if flagBuiltin {
benchmarkSortBuiltin(b)
} else {
benchmarkSortReflect(b)
}
}
func benchmarkSortReflect(b *testing.B) {
less := func(a, b int) bool { return a < b }
for i := 0; i < b.N; i++ {
b.StopTimer()
list := randIntSlice(1000, 0)
b.StartTimer()
Sort(less, list)
}
}
func benchmarkSortBuiltin(b *testing.B) {
for i := 0; i < b.N; i++ {
b.StopTimer()
list := randIntSlice(1000, 0)
b.StartTimer()
sort.Sort(sort.IntSlice(list))
}
}
func BenchmarkQuickSort(b *testing.B) {
if flagBuiltin {
benchmarkQuickSortBuiltin(b)
} else {
benchmarkQuickSortReflect(b)
}
}
func benchmarkQuickSortReflect(b *testing.B) {
less := func(a, b int) bool { return a < b }
for i := 0; i < b.N; i++ {
b.StopTimer()
list := randIntSlice(1000, 0)
b.StartTimer()
_ = QuickSort(less, list)
}
}
func benchmarkQuickSortBuiltin(b *testing.B) {
less := func(a, b int) bool { return a < b }
quicksort := func(xs []int) []int {
ys := make([]int, len(xs))
copy(ys, xs)
var qsort func(left, right int)
var partition func(left, right, pivot int) int
qsort = func(left, right int) {
if left >= right {
return
}
pivot := (left + right) / 2
pivot = partition(left, right, pivot)
qsort(left, pivot-1)
qsort(pivot+1, right)
}
partition = func(left, right, pivot int) int {
vpivot := ys[pivot]
ys[pivot], ys[right] = ys[right], ys[pivot]
ind := left
for i := left; i < right; i++ {
if less(ys[i], vpivot) {
ys[i], ys[ind] = ys[ind], ys[i]
ind++
}
}
ys[ind], ys[right] = ys[right], ys[ind]
return ind
}
return ys
}
for i := 0; i < b.N; i++ {
b.StopTimer()
list := randIntSlice(1000, 0)
b.StartTimer()
_ = quicksort(list)
}
}

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package fun
import (
"reflect"
)
func zeroValue(typ reflect.Type) reflect.Value {
return reflect.New(typ).Elem()
}
type swapper reflect.Value
func swapperOf(typ reflect.Type) swapper {
return swapper(zeroValue(typ))
}
func (s swapper) swap(a, b reflect.Value) {
vs := reflect.Value(s)
vs.Set(a)
a.Set(b)
b.Set(vs)
}
func call(f reflect.Value, args ...reflect.Value) {
f.Call(args)
}
func call1(f reflect.Value, args ...reflect.Value) reflect.Value {
return f.Call(args)[0]
}
func call2(f reflect.Value, args ...reflect.Value) (
reflect.Value, reflect.Value) {
ret := f.Call(args)
return ret[0], ret[1]
}

View file

@ -0,0 +1,35 @@
benchmark old ns/op new ns/op delta
BenchmarkFibonacciMemo-12 5895 43896 +644.63%
BenchmarkFibonacciNoMemo-12 6827001 6829859 +0.04%
BenchmarkParMapSquare-12 408320 572307 +40.16%
BenchmarkParMapPrime-12 5289594 5510075 +4.17%
BenchmarkMapSquare-12 8499 457844 +5287.03%
BenchmarkMapPrime-12 34265372 32220176 -5.97%
BenchmarkShuffle-12 240036 1018408 +324.27%
BenchmarkSample-12 262565 271122 +3.26%
BenchmarkSort-12 137293 7716737 +5520.63%
BenchmarkQuickSort-12 6325 6051563 +95576.89%
benchmark old allocs new allocs delta
BenchmarkFibonacciMemo-12 11 198 1700.00%
BenchmarkFibonacciNoMemo-12 0 0 n/a%
BenchmarkParMapSquare-12 21 2038 9604.76%
BenchmarkParMapPrime-12 7148 9160 28.15%
BenchmarkMapSquare-12 1 2014 201300.00%
BenchmarkMapPrime-12 7105 9173 29.11%
BenchmarkShuffle-12 0 7 n/a%
BenchmarkSample-12 2 11 450.00%
BenchmarkSort-12 1 27032 2703100.00%
BenchmarkQuickSort-12 1 22008 2200700.00%
benchmark old bytes new bytes delta
BenchmarkFibonacciMemo-12 2449 12083 393.39%
BenchmarkFibonacciNoMemo-12 0 0 n/a%
BenchmarkParMapSquare-12 9127 60330 561.01%
BenchmarkParMapPrime-12 156540 222731 42.28%
BenchmarkMapSquare-12 8195 58053 608.40%
BenchmarkMapPrime-12 155952 221255 41.87%
BenchmarkShuffle-12 0 500 n/a%
BenchmarkSample-12 82785 83383 0.72%
BenchmarkSort-12 35 883869 2525240.00%
BenchmarkQuickSort-12 8195 735645 8876.75%

View file

@ -0,0 +1 @@
au BufWritePost *.go silent!make tags > /dev/null 2>&1

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@ -0,0 +1,338 @@
package ty
import (
"fmt"
"reflect"
"strings"
)
// TypeError corresponds to any error reported by the `Check` function.
// Since `Check` panics, if you want to run `Check` safely, it is
// appropriate to recover and use a type switch to discover a `TypeError`
// value.
type TypeError string
func (te TypeError) Error() string {
return string(te)
}
func pe(format string, v ...interface{}) TypeError {
return TypeError(fmt.Sprintf(format, v...))
}
func ppe(format string, v ...interface{}) {
panic(pe(format, v...))
}
// Typed corresponds to the information returned by `Check`.
type Typed struct {
// In correspondence with the `as` parameter to `Check`.
Args []reflect.Value
// In correspondence with the return types of `f` in `Check`.
Returns []reflect.Type
// The type environment generated via unification in `Check`.
// (Its usefulness in the public API is questionable.)
TypeEnv map[string]reflect.Type
}
// Check accepts a function `f`, which may have a parametric type, along with a
// number of arguments in correspondence with the arguments to `f`,
// and returns inferred Go type information. This type information includes
// a list of `reflect.Value` in correspondence with `as`, a list of
// `reflect.Type` in correspondence with the return types of `f` and a type
// environment mapping type variables to `reflect.Type`.
//
// The power of `Check` comes from the following invariant: if `Check` returns,
// then the types of the arguments corresponding to `as` are consistent
// with the parametric type of `f`, *and* the parametric return types of `f`
// were made into valid Go types that are not parametric. Otherwise, there is
// a bug in `Check`.
//
// More concretely, consider a simple parametric function `Map`, which
// transforms a list of elements by applying a function to each element in
// order to generate a new list. Such a function constructed only for integers
// might have a type like
//
// func Map(func(int) int, []int) []int
//
// But the parametric type of `Map` could be given with
//
// func Map(func(A) B, []A) []B
//
// which in English reads, "Given a function from any type `A` to any type `B`
// and a slice of `A`, `Map` returns a slice of `B`."
//
// To write a parametric function like `Map`, one can pass a pointer
// to a nil function of the desired parametric type to get the reflection
// information:
//
// func Map(f, xs interface{}) interface{} {
// // Given the parametric type and the arguments, Check will
// // return all the reflection information you need to write `Map`.
// uni := ty.Check(
// new(func(func(ty.A) ty.B, []ty.A) []ty.B),
// f, xs)
//
// // `vf` and `vxs` are `reflect.Value`s of `f` and `xs`.
// vf, vxs := uni.Args[0], uni.Args[1]
//
// // `tys` is a `reflect.Type` of `[]ty.B` where `ty.B` is replaced
// // with the return type of the given function `f`.
// tys := uni.Returns[0]
//
// // Given the promise of `Check`, we now know that `vf` has
// // type `func(ty.A) ty.B` and `vxs` has type `[]ty.A`.
// xsLen := vxs.Len()
//
// // Constructs a new slice which will have type `[]ty.B`.
// vys := reflect.MakeSlice(tys, xsLen, xsLen)
//
// // Actually perform the `Map` operation, but in the world of
// // reflection.
// for i := 0; i < xsLen; i++ {
// vy := vf.Call([]reflect.Value{vxs.Index(i)})[0]
// vys.Index(i).Set(vy)
// }
//
// // The `reflect.Value.Interface` method is how we exit the world of
// // reflection. The onus is now on the caller to type assert it to
// // the appropriate type.
// return vys.Interface()
// }
//
// Working in the reflection world is certainly more inconvenient than writing
// regular Go code, but the information and invariants held by `Check` provide
// a more convenient experience than how one normally works with reflection.
// (Notice that there is no error-prone type switching or boiler plate to
// construct new types, since `Check` guarantees the types are consistent
// with the inputs for us.)
//
// And while writing such functions is still not so convenient,
// invoking them is simple:
//
// square := func(x int) int { return x * x }
// squared := Map(square, []int{1, 2, 3, 4, 5}).([]int)
//
// Restrictions
//
// There are a few restrictions imposed on the parametric return types of
// `f`: type variables may only be found in types that can be composed by the
// `reflect` package. This *only* includes channels, maps, pointers and slices.
// If a type variable is found in an array, function or struct, `Check` will
// panic.
//
// Also, type variables inside of structs are ignored in the types of the
// arguments `as`. This restriction may be lifted in the future.
//
// To be clear: type variables *may* appear in arrays or functions in the types
// of the arguments `as`.
func Check(f interface{}, as ...interface{}) *Typed {
rf := reflect.ValueOf(f)
tf := rf.Type()
if tf.Kind() == reflect.Ptr {
rf = reflect.Indirect(rf)
tf = rf.Type()
}
if tf.Kind() != reflect.Func {
ppe("The type of `f` must be a function, but it is a '%s'.", tf.Kind())
}
if tf.NumIn() != len(as) {
ppe("`f` expects %d arguments, but only %d were given.",
tf.NumIn(), len(as))
}
// Populate the argument value list.
args := make([]reflect.Value, len(as))
for i := 0; i < len(as); i++ {
args[i] = reflect.ValueOf(as[i])
}
// Populate our type variable environment through unification.
tyenv := make(tyenv)
for i := 0; i < len(args); i++ {
tp := typePair{tyenv, tf.In(i), args[i].Type()}
// Mutates the type variable environment.
if err := tp.unify(tp.param, tp.input); err != nil {
argTypes := make([]string, len(args))
for i := range args {
argTypes[i] = args[i].Type().String()
}
ppe("\nError type checking\n\t%s\nwith argument types\n\t(%s)\n%s",
tf, strings.Join(argTypes, ", "), err)
}
}
// Now substitute those types into the return types of `f`.
retTypes := make([]reflect.Type, tf.NumOut())
for i := 0; i < tf.NumOut(); i++ {
retTypes[i] = (&returnType{tyenv, tf.Out(i)}).tysubst(tf.Out(i))
}
return &Typed{args, retTypes, map[string]reflect.Type(tyenv)}
}
// tyenv maps type variable names to their inferred Go type.
type tyenv map[string]reflect.Type
// typePair represents a pair of types to be unified. They act as a way to
// report sensible error messages from within the unification algorithm.
//
// It also includes a type environment, which is mutated during unification.
type typePair struct {
tyenv tyenv
param reflect.Type
input reflect.Type
}
func (tp typePair) error(format string, v ...interface{}) error {
return pe("Type error when unifying type '%s' and '%s': %s",
tp.param, tp.input, fmt.Sprintf(format, v...))
}
// unify attempts to satisfy a pair of types, where the `param` type is the
// expected type of a function argument and the `input` type is the known
// type of a function argument. The `param` type may be parametric (that is,
// it may contain a type that is convertible to TypeVariable) but the
// `input` type may *not* be parametric.
//
// Any failure to unify the two types results in a panic.
//
// The end result of unification is a type environment: a set of substitutions
// from type variable to a Go type.
func (tp typePair) unify(param, input reflect.Type) error {
if tyname := tyvarName(input); len(tyname) > 0 {
return tp.error("Type variables are not allowed in the types of " +
"arguments.")
}
if tyname := tyvarName(param); len(tyname) > 0 {
if cur, ok := tp.tyenv[tyname]; ok && cur != input {
return tp.error("Type variable %s expected type '%s' but got '%s'.",
tyname, cur, input)
} else if !ok {
tp.tyenv[tyname] = input
}
return nil
}
if param.Kind() != input.Kind() {
return tp.error("Cannot unify different kinds of types '%s' and '%s'.",
param, input)
}
switch param.Kind() {
case reflect.Array:
return tp.unify(param.Elem(), input.Elem())
case reflect.Chan:
if param.ChanDir() != input.ChanDir() {
return tp.error("Cannot unify '%s' with '%s' "+
"(channel directions are different: '%s' != '%s').",
param, input, param.ChanDir(), input.ChanDir())
}
return tp.unify(param.Elem(), input.Elem())
case reflect.Func:
if param.NumIn() != input.NumIn() || param.NumOut() != input.NumOut() {
return tp.error("Cannot unify '%s' with '%s'.", param, input)
}
for i := 0; i < param.NumIn(); i++ {
if err := tp.unify(param.In(i), input.In(i)); err != nil {
return err
}
}
for i := 0; i < param.NumOut(); i++ {
if err := tp.unify(param.Out(i), input.Out(i)); err != nil {
return err
}
}
case reflect.Map:
if err := tp.unify(param.Key(), input.Key()); err != nil {
return err
}
return tp.unify(param.Elem(), input.Elem())
case reflect.Ptr:
return tp.unify(param.Elem(), input.Elem())
case reflect.Slice:
return tp.unify(param.Elem(), input.Elem())
}
// The only other container types are Interface and Struct.
// I am unsure about what to do with interfaces. Mind is fuzzy.
// Structs? I don't think it really makes much sense to use type
// variables inside of them.
return nil
}
// returnType corresponds to the type of a single return value of a function,
// in which the type may be parametric. It also contains a type environment
// constructed from unification.
type returnType struct {
tyenv tyenv
typ reflect.Type
}
func (rt returnType) panic(format string, v ...interface{}) {
ppe("Error substituting in return type '%s': %s",
rt.typ, fmt.Sprintf(format, v...))
}
// tysubst attempts to substitute all type variables within a single return
// type with their corresponding Go type from the type environment.
//
// tysubst will panic if a type variable is unbound, or if it encounters a
// type that cannot be dynamically created. Such types include arrays,
// functions and structs. (A limitation of the `reflect` package.)
func (rt returnType) tysubst(typ reflect.Type) reflect.Type {
if tyname := tyvarName(typ); len(tyname) > 0 {
if thetype, ok := rt.tyenv[tyname]; !ok {
rt.panic("Unbound type variable %s.", tyname)
} else {
return thetype
}
}
switch typ.Kind() {
case reflect.Array:
rt.panic("Cannot dynamically create Array types.")
case reflect.Chan:
return reflect.ChanOf(typ.ChanDir(), rt.tysubst(typ.Elem()))
case reflect.Func:
rt.panic("Cannot dynamically create Function types.")
case reflect.Interface:
// rt.panic("TODO")
// Not sure if this is right.
return typ
case reflect.Map:
return reflect.MapOf(rt.tysubst(typ.Key()), rt.tysubst(typ.Elem()))
case reflect.Ptr:
return reflect.PtrTo(rt.tysubst(typ.Elem()))
case reflect.Slice:
return reflect.SliceOf(rt.tysubst(typ.Elem()))
case reflect.Struct:
rt.panic("Cannot dynamically create Struct types.")
case reflect.UnsafePointer:
rt.panic("Cannot dynamically create unsafe.Pointer types.")
}
// We've covered all the composite types, so we're only left with
// base types.
return typ
}
func tyvarName(t reflect.Type) string {
if !t.ConvertibleTo(tyvarUnderlyingType) {
return ""
}
return t.Name()
}
// AssertType panics with a `TypeError` if `v` does not have type `t`.
// Otherwise, it returns the `reflect.Value` of `v`.
func AssertType(v interface{}, t reflect.Type) reflect.Value {
rv := reflect.ValueOf(v)
tv := rv.Type()
if tv != t {
ppe("Value '%v' has type '%s' but expected '%s'.", v, tv, t)
}
return rv
}

View file

@ -0,0 +1,28 @@
package ty
import (
"reflect"
)
// TypeVariable is the underlying type of every type variable used in
// parametric types. It should not be used directly. Instead, use
//
// type myOwnTypeVariable TypeVariable
//
// to create your own type variable. For your convenience, this package
// defines some type variables for you. (e.g., `A`, `B`, `C`, ...)
type TypeVariable struct {
noImitation struct{}
}
// tyvarUnderlyingType is used to discover types that are type variables.
// Namely, any type variable must be convertible to `TypeVariable`.
var tyvarUnderlyingType = reflect.TypeOf(TypeVariable{})
type A TypeVariable
type B TypeVariable
type C TypeVariable
type D TypeVariable
type E TypeVariable
type F TypeVariable
type G TypeVariable

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# Go's `text/template` package with newline elision
This is a fork of Go 1.4's [text/template](http://golang.org/pkg/text/template/) package with one addition: a backslash immediately after a closing delimiter will delete all subsequent newlines until a non-newline.
eg.
```
{{if true}}\
hello
{{end}}\
```
Will result in:
```
hello\n
```
Rather than:
```
\n
hello\n
\n
```

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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
/*
Package template implements data-driven templates for generating textual output.
To generate HTML output, see package html/template, which has the same interface
as this package but automatically secures HTML output against certain attacks.
Templates are executed by applying them to a data structure. Annotations in the
template refer to elements of the data structure (typically a field of a struct
or a key in a map) to control execution and derive values to be displayed.
Execution of the template walks the structure and sets the cursor, represented
by a period '.' and called "dot", to the value at the current location in the
structure as execution proceeds.
The input text for a template is UTF-8-encoded text in any format.
"Actions"--data evaluations or control structures--are delimited by
"{{" and "}}"; all text outside actions is copied to the output unchanged.
Actions may not span newlines, although comments can.
Once parsed, a template may be executed safely in parallel.
Here is a trivial example that prints "17 items are made of wool".
type Inventory struct {
Material string
Count uint
}
sweaters := Inventory{"wool", 17}
tmpl, err := template.New("test").Parse("{{.Count}} items are made of {{.Material}}")
if err != nil { panic(err) }
err = tmpl.Execute(os.Stdout, sweaters)
if err != nil { panic(err) }
More intricate examples appear below.
Actions
Here is the list of actions. "Arguments" and "pipelines" are evaluations of
data, defined in detail below.
*/
// {{/* a comment */}}
// A comment; discarded. May contain newlines.
// Comments do not nest and must start and end at the
// delimiters, as shown here.
/*
{{pipeline}}
The default textual representation of the value of the pipeline
is copied to the output.
{{if pipeline}} T1 {{end}}
If the value of the pipeline is empty, no output is generated;
otherwise, T1 is executed. The empty values are false, 0, any
nil pointer or interface value, and any array, slice, map, or
string of length zero.
Dot is unaffected.
{{if pipeline}} T1 {{else}} T0 {{end}}
If the value of the pipeline is empty, T0 is executed;
otherwise, T1 is executed. Dot is unaffected.
{{if pipeline}} T1 {{else if pipeline}} T0 {{end}}
To simplify the appearance of if-else chains, the else action
of an if may include another if directly; the effect is exactly
the same as writing
{{if pipeline}} T1 {{else}}{{if pipeline}} T0 {{end}}{{end}}
{{range pipeline}} T1 {{end}}
The value of the pipeline must be an array, slice, map, or channel.
If the value of the pipeline has length zero, nothing is output;
otherwise, dot is set to the successive elements of the array,
slice, or map and T1 is executed. If the value is a map and the
keys are of basic type with a defined order ("comparable"), the
elements will be visited in sorted key order.
{{range pipeline}} T1 {{else}} T0 {{end}}
The value of the pipeline must be an array, slice, map, or channel.
If the value of the pipeline has length zero, dot is unaffected and
T0 is executed; otherwise, dot is set to the successive elements
of the array, slice, or map and T1 is executed.
{{template "name"}}
The template with the specified name is executed with nil data.
{{template "name" pipeline}}
The template with the specified name is executed with dot set
to the value of the pipeline.
{{with pipeline}} T1 {{end}}
If the value of the pipeline is empty, no output is generated;
otherwise, dot is set to the value of the pipeline and T1 is
executed.
{{with pipeline}} T1 {{else}} T0 {{end}}
If the value of the pipeline is empty, dot is unaffected and T0
is executed; otherwise, dot is set to the value of the pipeline
and T1 is executed.
Arguments
An argument is a simple value, denoted by one of the following.
- A boolean, string, character, integer, floating-point, imaginary
or complex constant in Go syntax. These behave like Go's untyped
constants, although raw strings may not span newlines.
- The keyword nil, representing an untyped Go nil.
- The character '.' (period):
.
The result is the value of dot.
- A variable name, which is a (possibly empty) alphanumeric string
preceded by a dollar sign, such as
$piOver2
or
$
The result is the value of the variable.
Variables are described below.
- The name of a field of the data, which must be a struct, preceded
by a period, such as
.Field
The result is the value of the field. Field invocations may be
chained:
.Field1.Field2
Fields can also be evaluated on variables, including chaining:
$x.Field1.Field2
- The name of a key of the data, which must be a map, preceded
by a period, such as
.Key
The result is the map element value indexed by the key.
Key invocations may be chained and combined with fields to any
depth:
.Field1.Key1.Field2.Key2
Although the key must be an alphanumeric identifier, unlike with
field names they do not need to start with an upper case letter.
Keys can also be evaluated on variables, including chaining:
$x.key1.key2
- The name of a niladic method of the data, preceded by a period,
such as
.Method
The result is the value of invoking the method with dot as the
receiver, dot.Method(). Such a method must have one return value (of
any type) or two return values, the second of which is an error.
If it has two and the returned error is non-nil, execution terminates
and an error is returned to the caller as the value of Execute.
Method invocations may be chained and combined with fields and keys
to any depth:
.Field1.Key1.Method1.Field2.Key2.Method2
Methods can also be evaluated on variables, including chaining:
$x.Method1.Field
- The name of a niladic function, such as
fun
The result is the value of invoking the function, fun(). The return
types and values behave as in methods. Functions and function
names are described below.
- A parenthesized instance of one the above, for grouping. The result
may be accessed by a field or map key invocation.
print (.F1 arg1) (.F2 arg2)
(.StructValuedMethod "arg").Field
Arguments may evaluate to any type; if they are pointers the implementation
automatically indirects to the base type when required.
If an evaluation yields a function value, such as a function-valued
field of a struct, the function is not invoked automatically, but it
can be used as a truth value for an if action and the like. To invoke
it, use the call function, defined below.
A pipeline is a possibly chained sequence of "commands". A command is a simple
value (argument) or a function or method call, possibly with multiple arguments:
Argument
The result is the value of evaluating the argument.
.Method [Argument...]
The method can be alone or the last element of a chain but,
unlike methods in the middle of a chain, it can take arguments.
The result is the value of calling the method with the
arguments:
dot.Method(Argument1, etc.)
functionName [Argument...]
The result is the value of calling the function associated
with the name:
function(Argument1, etc.)
Functions and function names are described below.
Pipelines
A pipeline may be "chained" by separating a sequence of commands with pipeline
characters '|'. In a chained pipeline, the result of the each command is
passed as the last argument of the following command. The output of the final
command in the pipeline is the value of the pipeline.
The output of a command will be either one value or two values, the second of
which has type error. If that second value is present and evaluates to
non-nil, execution terminates and the error is returned to the caller of
Execute.
Variables
A pipeline inside an action may initialize a variable to capture the result.
The initialization has syntax
$variable := pipeline
where $variable is the name of the variable. An action that declares a
variable produces no output.
If a "range" action initializes a variable, the variable is set to the
successive elements of the iteration. Also, a "range" may declare two
variables, separated by a comma:
range $index, $element := pipeline
in which case $index and $element are set to the successive values of the
array/slice index or map key and element, respectively. Note that if there is
only one variable, it is assigned the element; this is opposite to the
convention in Go range clauses.
A variable's scope extends to the "end" action of the control structure ("if",
"with", or "range") in which it is declared, or to the end of the template if
there is no such control structure. A template invocation does not inherit
variables from the point of its invocation.
When execution begins, $ is set to the data argument passed to Execute, that is,
to the starting value of dot.
Examples
Here are some example one-line templates demonstrating pipelines and variables.
All produce the quoted word "output":
{{"\"output\""}}
A string constant.
{{`"output"`}}
A raw string constant.
{{printf "%q" "output"}}
A function call.
{{"output" | printf "%q"}}
A function call whose final argument comes from the previous
command.
{{printf "%q" (print "out" "put")}}
A parenthesized argument.
{{"put" | printf "%s%s" "out" | printf "%q"}}
A more elaborate call.
{{"output" | printf "%s" | printf "%q"}}
A longer chain.
{{with "output"}}{{printf "%q" .}}{{end}}
A with action using dot.
{{with $x := "output" | printf "%q"}}{{$x}}{{end}}
A with action that creates and uses a variable.
{{with $x := "output"}}{{printf "%q" $x}}{{end}}
A with action that uses the variable in another action.
{{with $x := "output"}}{{$x | printf "%q"}}{{end}}
The same, but pipelined.
Functions
During execution functions are found in two function maps: first in the
template, then in the global function map. By default, no functions are defined
in the template but the Funcs method can be used to add them.
Predefined global functions are named as follows.
and
Returns the boolean AND of its arguments by returning the
first empty argument or the last argument, that is,
"and x y" behaves as "if x then y else x". All the
arguments are evaluated.
call
Returns the result of calling the first argument, which
must be a function, with the remaining arguments as parameters.
Thus "call .X.Y 1 2" is, in Go notation, dot.X.Y(1, 2) where
Y is a func-valued field, map entry, or the like.
The first argument must be the result of an evaluation
that yields a value of function type (as distinct from
a predefined function such as print). The function must
return either one or two result values, the second of which
is of type error. If the arguments don't match the function
or the returned error value is non-nil, execution stops.
html
Returns the escaped HTML equivalent of the textual
representation of its arguments.
index
Returns the result of indexing its first argument by the
following arguments. Thus "index x 1 2 3" is, in Go syntax,
x[1][2][3]. Each indexed item must be a map, slice, or array.
js
Returns the escaped JavaScript equivalent of the textual
representation of its arguments.
len
Returns the integer length of its argument.
not
Returns the boolean negation of its single argument.
or
Returns the boolean OR of its arguments by returning the
first non-empty argument or the last argument, that is,
"or x y" behaves as "if x then x else y". All the
arguments are evaluated.
print
An alias for fmt.Sprint
printf
An alias for fmt.Sprintf
println
An alias for fmt.Sprintln
urlquery
Returns the escaped value of the textual representation of
its arguments in a form suitable for embedding in a URL query.
The boolean functions take any zero value to be false and a non-zero
value to be true.
There is also a set of binary comparison operators defined as
functions:
eq
Returns the boolean truth of arg1 == arg2
ne
Returns the boolean truth of arg1 != arg2
lt
Returns the boolean truth of arg1 < arg2
le
Returns the boolean truth of arg1 <= arg2
gt
Returns the boolean truth of arg1 > arg2
ge
Returns the boolean truth of arg1 >= arg2
For simpler multi-way equality tests, eq (only) accepts two or more
arguments and compares the second and subsequent to the first,
returning in effect
arg1==arg2 || arg1==arg3 || arg1==arg4 ...
(Unlike with || in Go, however, eq is a function call and all the
arguments will be evaluated.)
The comparison functions work on basic types only (or named basic
types, such as "type Celsius float32"). They implement the Go rules
for comparison of values, except that size and exact type are
ignored, so any integer value, signed or unsigned, may be compared
with any other integer value. (The arithmetic value is compared,
not the bit pattern, so all negative integers are less than all
unsigned integers.) However, as usual, one may not compare an int
with a float32 and so on.
Associated templates
Each template is named by a string specified when it is created. Also, each
template is associated with zero or more other templates that it may invoke by
name; such associations are transitive and form a name space of templates.
A template may use a template invocation to instantiate another associated
template; see the explanation of the "template" action above. The name must be
that of a template associated with the template that contains the invocation.
Nested template definitions
When parsing a template, another template may be defined and associated with the
template being parsed. Template definitions must appear at the top level of the
template, much like global variables in a Go program.
The syntax of such definitions is to surround each template declaration with a
"define" and "end" action.
The define action names the template being created by providing a string
constant. Here is a simple example:
`{{define "T1"}}ONE{{end}}
{{define "T2"}}TWO{{end}}
{{define "T3"}}{{template "T1"}} {{template "T2"}}{{end}}
{{template "T3"}}`
This defines two templates, T1 and T2, and a third T3 that invokes the other two
when it is executed. Finally it invokes T3. If executed this template will
produce the text
ONE TWO
By construction, a template may reside in only one association. If it's
necessary to have a template addressable from multiple associations, the
template definition must be parsed multiple times to create distinct *Template
values, or must be copied with the Clone or AddParseTree method.
Parse may be called multiple times to assemble the various associated templates;
see the ParseFiles and ParseGlob functions and methods for simple ways to parse
related templates stored in files.
A template may be executed directly or through ExecuteTemplate, which executes
an associated template identified by name. To invoke our example above, we
might write,
err := tmpl.Execute(os.Stdout, "no data needed")
if err != nil {
log.Fatalf("execution failed: %s", err)
}
or to invoke a particular template explicitly by name,
err := tmpl.ExecuteTemplate(os.Stdout, "T2", "no data needed")
if err != nil {
log.Fatalf("execution failed: %s", err)
}
*/
package template

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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package template_test
import (
"github.com/alecthomas/template"
"log"
"os"
)
func ExampleTemplate() {
// Define a template.
const letter = `
Dear {{.Name}},
{{if .Attended}}
It was a pleasure to see you at the wedding.{{else}}
It is a shame you couldn't make it to the wedding.{{end}}
{{with .Gift}}Thank you for the lovely {{.}}.
{{end}}
Best wishes,
Josie
`
// Prepare some data to insert into the template.
type Recipient struct {
Name, Gift string
Attended bool
}
var recipients = []Recipient{
{"Aunt Mildred", "bone china tea set", true},
{"Uncle John", "moleskin pants", false},
{"Cousin Rodney", "", false},
}
// Create a new template and parse the letter into it.
t := template.Must(template.New("letter").Parse(letter))
// Execute the template for each recipient.
for _, r := range recipients {
err := t.Execute(os.Stdout, r)
if err != nil {
log.Println("executing template:", err)
}
}
// Output:
// Dear Aunt Mildred,
//
// It was a pleasure to see you at the wedding.
// Thank you for the lovely bone china tea set.
//
// Best wishes,
// Josie
//
// Dear Uncle John,
//
// It is a shame you couldn't make it to the wedding.
// Thank you for the lovely moleskin pants.
//
// Best wishes,
// Josie
//
// Dear Cousin Rodney,
//
// It is a shame you couldn't make it to the wedding.
//
// Best wishes,
// Josie
}

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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package template_test
import (
"github.com/alecthomas/template"
"io"
"io/ioutil"
"log"
"os"
"path/filepath"
)
// templateFile defines the contents of a template to be stored in a file, for testing.
type templateFile struct {
name string
contents string
}
func createTestDir(files []templateFile) string {
dir, err := ioutil.TempDir("", "template")
if err != nil {
log.Fatal(err)
}
for _, file := range files {
f, err := os.Create(filepath.Join(dir, file.name))
if err != nil {
log.Fatal(err)
}
defer f.Close()
_, err = io.WriteString(f, file.contents)
if err != nil {
log.Fatal(err)
}
}
return dir
}
// Here we demonstrate loading a set of templates from a directory.
func ExampleTemplate_glob() {
// Here we create a temporary directory and populate it with our sample
// template definition files; usually the template files would already
// exist in some location known to the program.
dir := createTestDir([]templateFile{
// T0.tmpl is a plain template file that just invokes T1.
{"T0.tmpl", `T0 invokes T1: ({{template "T1"}})`},
// T1.tmpl defines a template, T1 that invokes T2.
{"T1.tmpl", `{{define "T1"}}T1 invokes T2: ({{template "T2"}}){{end}}`},
// T2.tmpl defines a template T2.
{"T2.tmpl", `{{define "T2"}}This is T2{{end}}`},
})
// Clean up after the test; another quirk of running as an example.
defer os.RemoveAll(dir)
// pattern is the glob pattern used to find all the template files.
pattern := filepath.Join(dir, "*.tmpl")
// Here starts the example proper.
// T0.tmpl is the first name matched, so it becomes the starting template,
// the value returned by ParseGlob.
tmpl := template.Must(template.ParseGlob(pattern))
err := tmpl.Execute(os.Stdout, nil)
if err != nil {
log.Fatalf("template execution: %s", err)
}
// Output:
// T0 invokes T1: (T1 invokes T2: (This is T2))
}
// This example demonstrates one way to share some templates
// and use them in different contexts. In this variant we add multiple driver
// templates by hand to an existing bundle of templates.
func ExampleTemplate_helpers() {
// Here we create a temporary directory and populate it with our sample
// template definition files; usually the template files would already
// exist in some location known to the program.
dir := createTestDir([]templateFile{
// T1.tmpl defines a template, T1 that invokes T2.
{"T1.tmpl", `{{define "T1"}}T1 invokes T2: ({{template "T2"}}){{end}}`},
// T2.tmpl defines a template T2.
{"T2.tmpl", `{{define "T2"}}This is T2{{end}}`},
})
// Clean up after the test; another quirk of running as an example.
defer os.RemoveAll(dir)
// pattern is the glob pattern used to find all the template files.
pattern := filepath.Join(dir, "*.tmpl")
// Here starts the example proper.
// Load the helpers.
templates := template.Must(template.ParseGlob(pattern))
// Add one driver template to the bunch; we do this with an explicit template definition.
_, err := templates.Parse("{{define `driver1`}}Driver 1 calls T1: ({{template `T1`}})\n{{end}}")
if err != nil {
log.Fatal("parsing driver1: ", err)
}
// Add another driver template.
_, err = templates.Parse("{{define `driver2`}}Driver 2 calls T2: ({{template `T2`}})\n{{end}}")
if err != nil {
log.Fatal("parsing driver2: ", err)
}
// We load all the templates before execution. This package does not require
// that behavior but html/template's escaping does, so it's a good habit.
err = templates.ExecuteTemplate(os.Stdout, "driver1", nil)
if err != nil {
log.Fatalf("driver1 execution: %s", err)
}
err = templates.ExecuteTemplate(os.Stdout, "driver2", nil)
if err != nil {
log.Fatalf("driver2 execution: %s", err)
}
// Output:
// Driver 1 calls T1: (T1 invokes T2: (This is T2))
// Driver 2 calls T2: (This is T2)
}
// This example demonstrates how to use one group of driver
// templates with distinct sets of helper templates.
func ExampleTemplate_share() {
// Here we create a temporary directory and populate it with our sample
// template definition files; usually the template files would already
// exist in some location known to the program.
dir := createTestDir([]templateFile{
// T0.tmpl is a plain template file that just invokes T1.
{"T0.tmpl", "T0 ({{.}} version) invokes T1: ({{template `T1`}})\n"},
// T1.tmpl defines a template, T1 that invokes T2. Note T2 is not defined
{"T1.tmpl", `{{define "T1"}}T1 invokes T2: ({{template "T2"}}){{end}}`},
})
// Clean up after the test; another quirk of running as an example.
defer os.RemoveAll(dir)
// pattern is the glob pattern used to find all the template files.
pattern := filepath.Join(dir, "*.tmpl")
// Here starts the example proper.
// Load the drivers.
drivers := template.Must(template.ParseGlob(pattern))
// We must define an implementation of the T2 template. First we clone
// the drivers, then add a definition of T2 to the template name space.
// 1. Clone the helper set to create a new name space from which to run them.
first, err := drivers.Clone()
if err != nil {
log.Fatal("cloning helpers: ", err)
}
// 2. Define T2, version A, and parse it.
_, err = first.Parse("{{define `T2`}}T2, version A{{end}}")
if err != nil {
log.Fatal("parsing T2: ", err)
}
// Now repeat the whole thing, using a different version of T2.
// 1. Clone the drivers.
second, err := drivers.Clone()
if err != nil {
log.Fatal("cloning drivers: ", err)
}
// 2. Define T2, version B, and parse it.
_, err = second.Parse("{{define `T2`}}T2, version B{{end}}")
if err != nil {
log.Fatal("parsing T2: ", err)
}
// Execute the templates in the reverse order to verify the
// first is unaffected by the second.
err = second.ExecuteTemplate(os.Stdout, "T0.tmpl", "second")
if err != nil {
log.Fatalf("second execution: %s", err)
}
err = first.ExecuteTemplate(os.Stdout, "T0.tmpl", "first")
if err != nil {
log.Fatalf("first: execution: %s", err)
}
// Output:
// T0 (second version) invokes T1: (T1 invokes T2: (T2, version B))
// T0 (first version) invokes T1: (T1 invokes T2: (T2, version A))
}

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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package template_test
import (
"github.com/alecthomas/template"
"log"
"os"
"strings"
)
// This example demonstrates a custom function to process template text.
// It installs the strings.Title function and uses it to
// Make Title Text Look Good In Our Template's Output.
func ExampleTemplate_func() {
// First we create a FuncMap with which to register the function.
funcMap := template.FuncMap{
// The name "title" is what the function will be called in the template text.
"title": strings.Title,
}
// A simple template definition to test our function.
// We print the input text several ways:
// - the original
// - title-cased
// - title-cased and then printed with %q
// - printed with %q and then title-cased.
const templateText = `
Input: {{printf "%q" .}}
Output 0: {{title .}}
Output 1: {{title . | printf "%q"}}
Output 2: {{printf "%q" . | title}}
`
// Create a template, add the function map, and parse the text.
tmpl, err := template.New("titleTest").Funcs(funcMap).Parse(templateText)
if err != nil {
log.Fatalf("parsing: %s", err)
}
// Run the template to verify the output.
err = tmpl.Execute(os.Stdout, "the go programming language")
if err != nil {
log.Fatalf("execution: %s", err)
}
// Output:
// Input: "the go programming language"
// Output 0: The Go Programming Language
// Output 1: "The Go Programming Language"
// Output 2: "The Go Programming Language"
}

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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package template
import (
"bytes"
"fmt"
"github.com/alecthomas/template/parse"
"io"
"reflect"
"runtime"
"sort"
"strings"
)
// state represents the state of an execution. It's not part of the
// template so that multiple executions of the same template
// can execute in parallel.
type state struct {
tmpl *Template
wr io.Writer
node parse.Node // current node, for errors
vars []variable // push-down stack of variable values.
}
// variable holds the dynamic value of a variable such as $, $x etc.
type variable struct {
name string
value reflect.Value
}
// push pushes a new variable on the stack.
func (s *state) push(name string, value reflect.Value) {
s.vars = append(s.vars, variable{name, value})
}
// mark returns the length of the variable stack.
func (s *state) mark() int {
return len(s.vars)
}
// pop pops the variable stack up to the mark.
func (s *state) pop(mark int) {
s.vars = s.vars[0:mark]
}
// setVar overwrites the top-nth variable on the stack. Used by range iterations.
func (s *state) setVar(n int, value reflect.Value) {
s.vars[len(s.vars)-n].value = value
}
// varValue returns the value of the named variable.
func (s *state) varValue(name string) reflect.Value {
for i := s.mark() - 1; i >= 0; i-- {
if s.vars[i].name == name {
return s.vars[i].value
}
}
s.errorf("undefined variable: %s", name)
return zero
}
var zero reflect.Value
// at marks the state to be on node n, for error reporting.
func (s *state) at(node parse.Node) {
s.node = node
}
// doublePercent returns the string with %'s replaced by %%, if necessary,
// so it can be used safely inside a Printf format string.
func doublePercent(str string) string {
if strings.Contains(str, "%") {
str = strings.Replace(str, "%", "%%", -1)
}
return str
}
// errorf formats the error and terminates processing.
func (s *state) errorf(format string, args ...interface{}) {
name := doublePercent(s.tmpl.Name())
if s.node == nil {
format = fmt.Sprintf("template: %s: %s", name, format)
} else {
location, context := s.tmpl.ErrorContext(s.node)
format = fmt.Sprintf("template: %s: executing %q at <%s>: %s", location, name, doublePercent(context), format)
}
panic(fmt.Errorf(format, args...))
}
// errRecover is the handler that turns panics into returns from the top
// level of Parse.
func errRecover(errp *error) {
e := recover()
if e != nil {
switch err := e.(type) {
case runtime.Error:
panic(e)
case error:
*errp = err
default:
panic(e)
}
}
}
// ExecuteTemplate applies the template associated with t that has the given name
// to the specified data object and writes the output to wr.
// If an error occurs executing the template or writing its output,
// execution stops, but partial results may already have been written to
// the output writer.
// A template may be executed safely in parallel.
func (t *Template) ExecuteTemplate(wr io.Writer, name string, data interface{}) error {
tmpl := t.tmpl[name]
if tmpl == nil {
return fmt.Errorf("template: no template %q associated with template %q", name, t.name)
}
return tmpl.Execute(wr, data)
}
// Execute applies a parsed template to the specified data object,
// and writes the output to wr.
// If an error occurs executing the template or writing its output,
// execution stops, but partial results may already have been written to
// the output writer.
// A template may be executed safely in parallel.
func (t *Template) Execute(wr io.Writer, data interface{}) (err error) {
defer errRecover(&err)
value := reflect.ValueOf(data)
state := &state{
tmpl: t,
wr: wr,
vars: []variable{{"$", value}},
}
t.init()
if t.Tree == nil || t.Root == nil {
var b bytes.Buffer
for name, tmpl := range t.tmpl {
if tmpl.Tree == nil || tmpl.Root == nil {
continue
}
if b.Len() > 0 {
b.WriteString(", ")
}
fmt.Fprintf(&b, "%q", name)
}
var s string
if b.Len() > 0 {
s = "; defined templates are: " + b.String()
}
state.errorf("%q is an incomplete or empty template%s", t.Name(), s)
}
state.walk(value, t.Root)
return
}
// Walk functions step through the major pieces of the template structure,
// generating output as they go.
func (s *state) walk(dot reflect.Value, node parse.Node) {
s.at(node)
switch node := node.(type) {
case *parse.ActionNode:
// Do not pop variables so they persist until next end.
// Also, if the action declares variables, don't print the result.
val := s.evalPipeline(dot, node.Pipe)
if len(node.Pipe.Decl) == 0 {
s.printValue(node, val)
}
case *parse.IfNode:
s.walkIfOrWith(parse.NodeIf, dot, node.Pipe, node.List, node.ElseList)
case *parse.ListNode:
for _, node := range node.Nodes {
s.walk(dot, node)
}
case *parse.RangeNode:
s.walkRange(dot, node)
case *parse.TemplateNode:
s.walkTemplate(dot, node)
case *parse.TextNode:
if _, err := s.wr.Write(node.Text); err != nil {
s.errorf("%s", err)
}
case *parse.WithNode:
s.walkIfOrWith(parse.NodeWith, dot, node.Pipe, node.List, node.ElseList)
default:
s.errorf("unknown node: %s", node)
}
}
// walkIfOrWith walks an 'if' or 'with' node. The two control structures
// are identical in behavior except that 'with' sets dot.
func (s *state) walkIfOrWith(typ parse.NodeType, dot reflect.Value, pipe *parse.PipeNode, list, elseList *parse.ListNode) {
defer s.pop(s.mark())
val := s.evalPipeline(dot, pipe)
truth, ok := isTrue(val)
if !ok {
s.errorf("if/with can't use %v", val)
}
if truth {
if typ == parse.NodeWith {
s.walk(val, list)
} else {
s.walk(dot, list)
}
} else if elseList != nil {
s.walk(dot, elseList)
}
}
// isTrue reports whether the value is 'true', in the sense of not the zero of its type,
// and whether the value has a meaningful truth value.
func isTrue(val reflect.Value) (truth, ok bool) {
if !val.IsValid() {
// Something like var x interface{}, never set. It's a form of nil.
return false, true
}
switch val.Kind() {
case reflect.Array, reflect.Map, reflect.Slice, reflect.String:
truth = val.Len() > 0
case reflect.Bool:
truth = val.Bool()
case reflect.Complex64, reflect.Complex128:
truth = val.Complex() != 0
case reflect.Chan, reflect.Func, reflect.Ptr, reflect.Interface:
truth = !val.IsNil()
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
truth = val.Int() != 0
case reflect.Float32, reflect.Float64:
truth = val.Float() != 0
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
truth = val.Uint() != 0
case reflect.Struct:
truth = true // Struct values are always true.
default:
return
}
return truth, true
}
func (s *state) walkRange(dot reflect.Value, r *parse.RangeNode) {
s.at(r)
defer s.pop(s.mark())
val, _ := indirect(s.evalPipeline(dot, r.Pipe))
// mark top of stack before any variables in the body are pushed.
mark := s.mark()
oneIteration := func(index, elem reflect.Value) {
// Set top var (lexically the second if there are two) to the element.
if len(r.Pipe.Decl) > 0 {
s.setVar(1, elem)
}
// Set next var (lexically the first if there are two) to the index.
if len(r.Pipe.Decl) > 1 {
s.setVar(2, index)
}
s.walk(elem, r.List)
s.pop(mark)
}
switch val.Kind() {
case reflect.Array, reflect.Slice:
if val.Len() == 0 {
break
}
for i := 0; i < val.Len(); i++ {
oneIteration(reflect.ValueOf(i), val.Index(i))
}
return
case reflect.Map:
if val.Len() == 0 {
break
}
for _, key := range sortKeys(val.MapKeys()) {
oneIteration(key, val.MapIndex(key))
}
return
case reflect.Chan:
if val.IsNil() {
break
}
i := 0
for ; ; i++ {
elem, ok := val.Recv()
if !ok {
break
}
oneIteration(reflect.ValueOf(i), elem)
}
if i == 0 {
break
}
return
case reflect.Invalid:
break // An invalid value is likely a nil map, etc. and acts like an empty map.
default:
s.errorf("range can't iterate over %v", val)
}
if r.ElseList != nil {
s.walk(dot, r.ElseList)
}
}
func (s *state) walkTemplate(dot reflect.Value, t *parse.TemplateNode) {
s.at(t)
tmpl := s.tmpl.tmpl[t.Name]
if tmpl == nil {
s.errorf("template %q not defined", t.Name)
}
// Variables declared by the pipeline persist.
dot = s.evalPipeline(dot, t.Pipe)
newState := *s
newState.tmpl = tmpl
// No dynamic scoping: template invocations inherit no variables.
newState.vars = []variable{{"$", dot}}
newState.walk(dot, tmpl.Root)
}
// Eval functions evaluate pipelines, commands, and their elements and extract
// values from the data structure by examining fields, calling methods, and so on.
// The printing of those values happens only through walk functions.
// evalPipeline returns the value acquired by evaluating a pipeline. If the
// pipeline has a variable declaration, the variable will be pushed on the
// stack. Callers should therefore pop the stack after they are finished
// executing commands depending on the pipeline value.
func (s *state) evalPipeline(dot reflect.Value, pipe *parse.PipeNode) (value reflect.Value) {
if pipe == nil {
return
}
s.at(pipe)
for _, cmd := range pipe.Cmds {
value = s.evalCommand(dot, cmd, value) // previous value is this one's final arg.
// If the object has type interface{}, dig down one level to the thing inside.
if value.Kind() == reflect.Interface && value.Type().NumMethod() == 0 {
value = reflect.ValueOf(value.Interface()) // lovely!
}
}
for _, variable := range pipe.Decl {
s.push(variable.Ident[0], value)
}
return value
}
func (s *state) notAFunction(args []parse.Node, final reflect.Value) {
if len(args) > 1 || final.IsValid() {
s.errorf("can't give argument to non-function %s", args[0])
}
}
func (s *state) evalCommand(dot reflect.Value, cmd *parse.CommandNode, final reflect.Value) reflect.Value {
firstWord := cmd.Args[0]
switch n := firstWord.(type) {
case *parse.FieldNode:
return s.evalFieldNode(dot, n, cmd.Args, final)
case *parse.ChainNode:
return s.evalChainNode(dot, n, cmd.Args, final)
case *parse.IdentifierNode:
// Must be a function.
return s.evalFunction(dot, n, cmd, cmd.Args, final)
case *parse.PipeNode:
// Parenthesized pipeline. The arguments are all inside the pipeline; final is ignored.
return s.evalPipeline(dot, n)
case *parse.VariableNode:
return s.evalVariableNode(dot, n, cmd.Args, final)
}
s.at(firstWord)
s.notAFunction(cmd.Args, final)
switch word := firstWord.(type) {
case *parse.BoolNode:
return reflect.ValueOf(word.True)
case *parse.DotNode:
return dot
case *parse.NilNode:
s.errorf("nil is not a command")
case *parse.NumberNode:
return s.idealConstant(word)
case *parse.StringNode:
return reflect.ValueOf(word.Text)
}
s.errorf("can't evaluate command %q", firstWord)
panic("not reached")
}
// idealConstant is called to return the value of a number in a context where
// we don't know the type. In that case, the syntax of the number tells us
// its type, and we use Go rules to resolve. Note there is no such thing as
// a uint ideal constant in this situation - the value must be of int type.
func (s *state) idealConstant(constant *parse.NumberNode) reflect.Value {
// These are ideal constants but we don't know the type
// and we have no context. (If it was a method argument,
// we'd know what we need.) The syntax guides us to some extent.
s.at(constant)
switch {
case constant.IsComplex:
return reflect.ValueOf(constant.Complex128) // incontrovertible.
case constant.IsFloat && !isHexConstant(constant.Text) && strings.IndexAny(constant.Text, ".eE") >= 0:
return reflect.ValueOf(constant.Float64)
case constant.IsInt:
n := int(constant.Int64)
if int64(n) != constant.Int64 {
s.errorf("%s overflows int", constant.Text)
}
return reflect.ValueOf(n)
case constant.IsUint:
s.errorf("%s overflows int", constant.Text)
}
return zero
}
func isHexConstant(s string) bool {
return len(s) > 2 && s[0] == '0' && (s[1] == 'x' || s[1] == 'X')
}
func (s *state) evalFieldNode(dot reflect.Value, field *parse.FieldNode, args []parse.Node, final reflect.Value) reflect.Value {
s.at(field)
return s.evalFieldChain(dot, dot, field, field.Ident, args, final)
}
func (s *state) evalChainNode(dot reflect.Value, chain *parse.ChainNode, args []parse.Node, final reflect.Value) reflect.Value {
s.at(chain)
// (pipe).Field1.Field2 has pipe as .Node, fields as .Field. Eval the pipeline, then the fields.
pipe := s.evalArg(dot, nil, chain.Node)
if len(chain.Field) == 0 {
s.errorf("internal error: no fields in evalChainNode")
}
return s.evalFieldChain(dot, pipe, chain, chain.Field, args, final)
}
func (s *state) evalVariableNode(dot reflect.Value, variable *parse.VariableNode, args []parse.Node, final reflect.Value) reflect.Value {
// $x.Field has $x as the first ident, Field as the second. Eval the var, then the fields.
s.at(variable)
value := s.varValue(variable.Ident[0])
if len(variable.Ident) == 1 {
s.notAFunction(args, final)
return value
}
return s.evalFieldChain(dot, value, variable, variable.Ident[1:], args, final)
}
// evalFieldChain evaluates .X.Y.Z possibly followed by arguments.
// dot is the environment in which to evaluate arguments, while
// receiver is the value being walked along the chain.
func (s *state) evalFieldChain(dot, receiver reflect.Value, node parse.Node, ident []string, args []parse.Node, final reflect.Value) reflect.Value {
n := len(ident)
for i := 0; i < n-1; i++ {
receiver = s.evalField(dot, ident[i], node, nil, zero, receiver)
}
// Now if it's a method, it gets the arguments.
return s.evalField(dot, ident[n-1], node, args, final, receiver)
}
func (s *state) evalFunction(dot reflect.Value, node *parse.IdentifierNode, cmd parse.Node, args []parse.Node, final reflect.Value) reflect.Value {
s.at(node)
name := node.Ident
function, ok := findFunction(name, s.tmpl)
if !ok {
s.errorf("%q is not a defined function", name)
}
return s.evalCall(dot, function, cmd, name, args, final)
}
// evalField evaluates an expression like (.Field) or (.Field arg1 arg2).
// The 'final' argument represents the return value from the preceding
// value of the pipeline, if any.
func (s *state) evalField(dot reflect.Value, fieldName string, node parse.Node, args []parse.Node, final, receiver reflect.Value) reflect.Value {
if !receiver.IsValid() {
return zero
}
typ := receiver.Type()
receiver, _ = indirect(receiver)
// Unless it's an interface, need to get to a value of type *T to guarantee
// we see all methods of T and *T.
ptr := receiver
if ptr.Kind() != reflect.Interface && ptr.CanAddr() {
ptr = ptr.Addr()
}
if method := ptr.MethodByName(fieldName); method.IsValid() {
return s.evalCall(dot, method, node, fieldName, args, final)
}
hasArgs := len(args) > 1 || final.IsValid()
// It's not a method; must be a field of a struct or an element of a map. The receiver must not be nil.
receiver, isNil := indirect(receiver)
if isNil {
s.errorf("nil pointer evaluating %s.%s", typ, fieldName)
}
switch receiver.Kind() {
case reflect.Struct:
tField, ok := receiver.Type().FieldByName(fieldName)
if ok {
field := receiver.FieldByIndex(tField.Index)
if tField.PkgPath != "" { // field is unexported
s.errorf("%s is an unexported field of struct type %s", fieldName, typ)
}
// If it's a function, we must call it.
if hasArgs {
s.errorf("%s has arguments but cannot be invoked as function", fieldName)
}
return field
}
s.errorf("%s is not a field of struct type %s", fieldName, typ)
case reflect.Map:
// If it's a map, attempt to use the field name as a key.
nameVal := reflect.ValueOf(fieldName)
if nameVal.Type().AssignableTo(receiver.Type().Key()) {
if hasArgs {
s.errorf("%s is not a method but has arguments", fieldName)
}
return receiver.MapIndex(nameVal)
}
}
s.errorf("can't evaluate field %s in type %s", fieldName, typ)
panic("not reached")
}
var (
errorType = reflect.TypeOf((*error)(nil)).Elem()
fmtStringerType = reflect.TypeOf((*fmt.Stringer)(nil)).Elem()
)
// evalCall executes a function or method call. If it's a method, fun already has the receiver bound, so
// it looks just like a function call. The arg list, if non-nil, includes (in the manner of the shell), arg[0]
// as the function itself.
func (s *state) evalCall(dot, fun reflect.Value, node parse.Node, name string, args []parse.Node, final reflect.Value) reflect.Value {
if args != nil {
args = args[1:] // Zeroth arg is function name/node; not passed to function.
}
typ := fun.Type()
numIn := len(args)
if final.IsValid() {
numIn++
}
numFixed := len(args)
if typ.IsVariadic() {
numFixed = typ.NumIn() - 1 // last arg is the variadic one.
if numIn < numFixed {
s.errorf("wrong number of args for %s: want at least %d got %d", name, typ.NumIn()-1, len(args))
}
} else if numIn < typ.NumIn()-1 || !typ.IsVariadic() && numIn != typ.NumIn() {
s.errorf("wrong number of args for %s: want %d got %d", name, typ.NumIn(), len(args))
}
if !goodFunc(typ) {
// TODO: This could still be a confusing error; maybe goodFunc should provide info.
s.errorf("can't call method/function %q with %d results", name, typ.NumOut())
}
// Build the arg list.
argv := make([]reflect.Value, numIn)
// Args must be evaluated. Fixed args first.
i := 0
for ; i < numFixed && i < len(args); i++ {
argv[i] = s.evalArg(dot, typ.In(i), args[i])
}
// Now the ... args.
if typ.IsVariadic() {
argType := typ.In(typ.NumIn() - 1).Elem() // Argument is a slice.
for ; i < len(args); i++ {
argv[i] = s.evalArg(dot, argType, args[i])
}
}
// Add final value if necessary.
if final.IsValid() {
t := typ.In(typ.NumIn() - 1)
if typ.IsVariadic() {
t = t.Elem()
}
argv[i] = s.validateType(final, t)
}
result := fun.Call(argv)
// If we have an error that is not nil, stop execution and return that error to the caller.
if len(result) == 2 && !result[1].IsNil() {
s.at(node)
s.errorf("error calling %s: %s", name, result[1].Interface().(error))
}
return result[0]
}
// canBeNil reports whether an untyped nil can be assigned to the type. See reflect.Zero.
func canBeNil(typ reflect.Type) bool {
switch typ.Kind() {
case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice:
return true
}
return false
}
// validateType guarantees that the value is valid and assignable to the type.
func (s *state) validateType(value reflect.Value, typ reflect.Type) reflect.Value {
if !value.IsValid() {
if typ == nil || canBeNil(typ) {
// An untyped nil interface{}. Accept as a proper nil value.
return reflect.Zero(typ)
}
s.errorf("invalid value; expected %s", typ)
}
if typ != nil && !value.Type().AssignableTo(typ) {
if value.Kind() == reflect.Interface && !value.IsNil() {
value = value.Elem()
if value.Type().AssignableTo(typ) {
return value
}
// fallthrough
}
// Does one dereference or indirection work? We could do more, as we
// do with method receivers, but that gets messy and method receivers
// are much more constrained, so it makes more sense there than here.
// Besides, one is almost always all you need.
switch {
case value.Kind() == reflect.Ptr && value.Type().Elem().AssignableTo(typ):
value = value.Elem()
if !value.IsValid() {
s.errorf("dereference of nil pointer of type %s", typ)
}
case reflect.PtrTo(value.Type()).AssignableTo(typ) && value.CanAddr():
value = value.Addr()
default:
s.errorf("wrong type for value; expected %s; got %s", typ, value.Type())
}
}
return value
}
func (s *state) evalArg(dot reflect.Value, typ reflect.Type, n parse.Node) reflect.Value {
s.at(n)
switch arg := n.(type) {
case *parse.DotNode:
return s.validateType(dot, typ)
case *parse.NilNode:
if canBeNil(typ) {
return reflect.Zero(typ)
}
s.errorf("cannot assign nil to %s", typ)
case *parse.FieldNode:
return s.validateType(s.evalFieldNode(dot, arg, []parse.Node{n}, zero), typ)
case *parse.VariableNode:
return s.validateType(s.evalVariableNode(dot, arg, nil, zero), typ)
case *parse.PipeNode:
return s.validateType(s.evalPipeline(dot, arg), typ)
case *parse.IdentifierNode:
return s.evalFunction(dot, arg, arg, nil, zero)
case *parse.ChainNode:
return s.validateType(s.evalChainNode(dot, arg, nil, zero), typ)
}
switch typ.Kind() {
case reflect.Bool:
return s.evalBool(typ, n)
case reflect.Complex64, reflect.Complex128:
return s.evalComplex(typ, n)
case reflect.Float32, reflect.Float64:
return s.evalFloat(typ, n)
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return s.evalInteger(typ, n)
case reflect.Interface:
if typ.NumMethod() == 0 {
return s.evalEmptyInterface(dot, n)
}
case reflect.String:
return s.evalString(typ, n)
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return s.evalUnsignedInteger(typ, n)
}
s.errorf("can't handle %s for arg of type %s", n, typ)
panic("not reached")
}
func (s *state) evalBool(typ reflect.Type, n parse.Node) reflect.Value {
s.at(n)
if n, ok := n.(*parse.BoolNode); ok {
value := reflect.New(typ).Elem()
value.SetBool(n.True)
return value
}
s.errorf("expected bool; found %s", n)
panic("not reached")
}
func (s *state) evalString(typ reflect.Type, n parse.Node) reflect.Value {
s.at(n)
if n, ok := n.(*parse.StringNode); ok {
value := reflect.New(typ).Elem()
value.SetString(n.Text)
return value
}
s.errorf("expected string; found %s", n)
panic("not reached")
}
func (s *state) evalInteger(typ reflect.Type, n parse.Node) reflect.Value {
s.at(n)
if n, ok := n.(*parse.NumberNode); ok && n.IsInt {
value := reflect.New(typ).Elem()
value.SetInt(n.Int64)
return value
}
s.errorf("expected integer; found %s", n)
panic("not reached")
}
func (s *state) evalUnsignedInteger(typ reflect.Type, n parse.Node) reflect.Value {
s.at(n)
if n, ok := n.(*parse.NumberNode); ok && n.IsUint {
value := reflect.New(typ).Elem()
value.SetUint(n.Uint64)
return value
}
s.errorf("expected unsigned integer; found %s", n)
panic("not reached")
}
func (s *state) evalFloat(typ reflect.Type, n parse.Node) reflect.Value {
s.at(n)
if n, ok := n.(*parse.NumberNode); ok && n.IsFloat {
value := reflect.New(typ).Elem()
value.SetFloat(n.Float64)
return value
}
s.errorf("expected float; found %s", n)
panic("not reached")
}
func (s *state) evalComplex(typ reflect.Type, n parse.Node) reflect.Value {
if n, ok := n.(*parse.NumberNode); ok && n.IsComplex {
value := reflect.New(typ).Elem()
value.SetComplex(n.Complex128)
return value
}
s.errorf("expected complex; found %s", n)
panic("not reached")
}
func (s *state) evalEmptyInterface(dot reflect.Value, n parse.Node) reflect.Value {
s.at(n)
switch n := n.(type) {
case *parse.BoolNode:
return reflect.ValueOf(n.True)
case *parse.DotNode:
return dot
case *parse.FieldNode:
return s.evalFieldNode(dot, n, nil, zero)
case *parse.IdentifierNode:
return s.evalFunction(dot, n, n, nil, zero)
case *parse.NilNode:
// NilNode is handled in evalArg, the only place that calls here.
s.errorf("evalEmptyInterface: nil (can't happen)")
case *parse.NumberNode:
return s.idealConstant(n)
case *parse.StringNode:
return reflect.ValueOf(n.Text)
case *parse.VariableNode:
return s.evalVariableNode(dot, n, nil, zero)
case *parse.PipeNode:
return s.evalPipeline(dot, n)
}
s.errorf("can't handle assignment of %s to empty interface argument", n)
panic("not reached")
}
// indirect returns the item at the end of indirection, and a bool to indicate if it's nil.
// We indirect through pointers and empty interfaces (only) because
// non-empty interfaces have methods we might need.
func indirect(v reflect.Value) (rv reflect.Value, isNil bool) {
for ; v.Kind() == reflect.Ptr || v.Kind() == reflect.Interface; v = v.Elem() {
if v.IsNil() {
return v, true
}
if v.Kind() == reflect.Interface && v.NumMethod() > 0 {
break
}
}
return v, false
}
// printValue writes the textual representation of the value to the output of
// the template.
func (s *state) printValue(n parse.Node, v reflect.Value) {
s.at(n)
iface, ok := printableValue(v)
if !ok {
s.errorf("can't print %s of type %s", n, v.Type())
}
fmt.Fprint(s.wr, iface)
}
// printableValue returns the, possibly indirected, interface value inside v that
// is best for a call to formatted printer.
func printableValue(v reflect.Value) (interface{}, bool) {
if v.Kind() == reflect.Ptr {
v, _ = indirect(v) // fmt.Fprint handles nil.
}
if !v.IsValid() {
return "<no value>", true
}
if !v.Type().Implements(errorType) && !v.Type().Implements(fmtStringerType) {
if v.CanAddr() && (reflect.PtrTo(v.Type()).Implements(errorType) || reflect.PtrTo(v.Type()).Implements(fmtStringerType)) {
v = v.Addr()
} else {
switch v.Kind() {
case reflect.Chan, reflect.Func:
return nil, false
}
}
}
return v.Interface(), true
}
// Types to help sort the keys in a map for reproducible output.
type rvs []reflect.Value
func (x rvs) Len() int { return len(x) }
func (x rvs) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
type rvInts struct{ rvs }
func (x rvInts) Less(i, j int) bool { return x.rvs[i].Int() < x.rvs[j].Int() }
type rvUints struct{ rvs }
func (x rvUints) Less(i, j int) bool { return x.rvs[i].Uint() < x.rvs[j].Uint() }
type rvFloats struct{ rvs }
func (x rvFloats) Less(i, j int) bool { return x.rvs[i].Float() < x.rvs[j].Float() }
type rvStrings struct{ rvs }
func (x rvStrings) Less(i, j int) bool { return x.rvs[i].String() < x.rvs[j].String() }
// sortKeys sorts (if it can) the slice of reflect.Values, which is a slice of map keys.
func sortKeys(v []reflect.Value) []reflect.Value {
if len(v) <= 1 {
return v
}
switch v[0].Kind() {
case reflect.Float32, reflect.Float64:
sort.Sort(rvFloats{v})
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
sort.Sort(rvInts{v})
case reflect.String:
sort.Sort(rvStrings{v})
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
sort.Sort(rvUints{v})
}
return v
}

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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package template
import (
"bytes"
"errors"
"fmt"
"io"
"net/url"
"reflect"
"strings"
"unicode"
"unicode/utf8"
)
// FuncMap is the type of the map defining the mapping from names to functions.
// Each function must have either a single return value, or two return values of
// which the second has type error. In that case, if the second (error)
// return value evaluates to non-nil during execution, execution terminates and
// Execute returns that error.
type FuncMap map[string]interface{}
var builtins = FuncMap{
"and": and,
"call": call,
"html": HTMLEscaper,
"index": index,
"js": JSEscaper,
"len": length,
"not": not,
"or": or,
"print": fmt.Sprint,
"printf": fmt.Sprintf,
"println": fmt.Sprintln,
"urlquery": URLQueryEscaper,
// Comparisons
"eq": eq, // ==
"ge": ge, // >=
"gt": gt, // >
"le": le, // <=
"lt": lt, // <
"ne": ne, // !=
}
var builtinFuncs = createValueFuncs(builtins)
// createValueFuncs turns a FuncMap into a map[string]reflect.Value
func createValueFuncs(funcMap FuncMap) map[string]reflect.Value {
m := make(map[string]reflect.Value)
addValueFuncs(m, funcMap)
return m
}
// addValueFuncs adds to values the functions in funcs, converting them to reflect.Values.
func addValueFuncs(out map[string]reflect.Value, in FuncMap) {
for name, fn := range in {
v := reflect.ValueOf(fn)
if v.Kind() != reflect.Func {
panic("value for " + name + " not a function")
}
if !goodFunc(v.Type()) {
panic(fmt.Errorf("can't install method/function %q with %d results", name, v.Type().NumOut()))
}
out[name] = v
}
}
// addFuncs adds to values the functions in funcs. It does no checking of the input -
// call addValueFuncs first.
func addFuncs(out, in FuncMap) {
for name, fn := range in {
out[name] = fn
}
}
// goodFunc checks that the function or method has the right result signature.
func goodFunc(typ reflect.Type) bool {
// We allow functions with 1 result or 2 results where the second is an error.
switch {
case typ.NumOut() == 1:
return true
case typ.NumOut() == 2 && typ.Out(1) == errorType:
return true
}
return false
}
// findFunction looks for a function in the template, and global map.
func findFunction(name string, tmpl *Template) (reflect.Value, bool) {
if tmpl != nil && tmpl.common != nil {
if fn := tmpl.execFuncs[name]; fn.IsValid() {
return fn, true
}
}
if fn := builtinFuncs[name]; fn.IsValid() {
return fn, true
}
return reflect.Value{}, false
}
// Indexing.
// index returns the result of indexing its first argument by the following
// arguments. Thus "index x 1 2 3" is, in Go syntax, x[1][2][3]. Each
// indexed item must be a map, slice, or array.
func index(item interface{}, indices ...interface{}) (interface{}, error) {
v := reflect.ValueOf(item)
for _, i := range indices {
index := reflect.ValueOf(i)
var isNil bool
if v, isNil = indirect(v); isNil {
return nil, fmt.Errorf("index of nil pointer")
}
switch v.Kind() {
case reflect.Array, reflect.Slice, reflect.String:
var x int64
switch index.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
x = index.Int()
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
x = int64(index.Uint())
default:
return nil, fmt.Errorf("cannot index slice/array with type %s", index.Type())
}
if x < 0 || x >= int64(v.Len()) {
return nil, fmt.Errorf("index out of range: %d", x)
}
v = v.Index(int(x))
case reflect.Map:
if !index.IsValid() {
index = reflect.Zero(v.Type().Key())
}
if !index.Type().AssignableTo(v.Type().Key()) {
return nil, fmt.Errorf("%s is not index type for %s", index.Type(), v.Type())
}
if x := v.MapIndex(index); x.IsValid() {
v = x
} else {
v = reflect.Zero(v.Type().Elem())
}
default:
return nil, fmt.Errorf("can't index item of type %s", v.Type())
}
}
return v.Interface(), nil
}
// Length
// length returns the length of the item, with an error if it has no defined length.
func length(item interface{}) (int, error) {
v, isNil := indirect(reflect.ValueOf(item))
if isNil {
return 0, fmt.Errorf("len of nil pointer")
}
switch v.Kind() {
case reflect.Array, reflect.Chan, reflect.Map, reflect.Slice, reflect.String:
return v.Len(), nil
}
return 0, fmt.Errorf("len of type %s", v.Type())
}
// Function invocation
// call returns the result of evaluating the first argument as a function.
// The function must return 1 result, or 2 results, the second of which is an error.
func call(fn interface{}, args ...interface{}) (interface{}, error) {
v := reflect.ValueOf(fn)
typ := v.Type()
if typ.Kind() != reflect.Func {
return nil, fmt.Errorf("non-function of type %s", typ)
}
if !goodFunc(typ) {
return nil, fmt.Errorf("function called with %d args; should be 1 or 2", typ.NumOut())
}
numIn := typ.NumIn()
var dddType reflect.Type
if typ.IsVariadic() {
if len(args) < numIn-1 {
return nil, fmt.Errorf("wrong number of args: got %d want at least %d", len(args), numIn-1)
}
dddType = typ.In(numIn - 1).Elem()
} else {
if len(args) != numIn {
return nil, fmt.Errorf("wrong number of args: got %d want %d", len(args), numIn)
}
}
argv := make([]reflect.Value, len(args))
for i, arg := range args {
value := reflect.ValueOf(arg)
// Compute the expected type. Clumsy because of variadics.
var argType reflect.Type
if !typ.IsVariadic() || i < numIn-1 {
argType = typ.In(i)
} else {
argType = dddType
}
if !value.IsValid() && canBeNil(argType) {
value = reflect.Zero(argType)
}
if !value.Type().AssignableTo(argType) {
return nil, fmt.Errorf("arg %d has type %s; should be %s", i, value.Type(), argType)
}
argv[i] = value
}
result := v.Call(argv)
if len(result) == 2 && !result[1].IsNil() {
return result[0].Interface(), result[1].Interface().(error)
}
return result[0].Interface(), nil
}
// Boolean logic.
func truth(a interface{}) bool {
t, _ := isTrue(reflect.ValueOf(a))
return t
}
// and computes the Boolean AND of its arguments, returning
// the first false argument it encounters, or the last argument.
func and(arg0 interface{}, args ...interface{}) interface{} {
if !truth(arg0) {
return arg0
}
for i := range args {
arg0 = args[i]
if !truth(arg0) {
break
}
}
return arg0
}
// or computes the Boolean OR of its arguments, returning
// the first true argument it encounters, or the last argument.
func or(arg0 interface{}, args ...interface{}) interface{} {
if truth(arg0) {
return arg0
}
for i := range args {
arg0 = args[i]
if truth(arg0) {
break
}
}
return arg0
}
// not returns the Boolean negation of its argument.
func not(arg interface{}) (truth bool) {
truth, _ = isTrue(reflect.ValueOf(arg))
return !truth
}
// Comparison.
// TODO: Perhaps allow comparison between signed and unsigned integers.
var (
errBadComparisonType = errors.New("invalid type for comparison")
errBadComparison = errors.New("incompatible types for comparison")
errNoComparison = errors.New("missing argument for comparison")
)
type kind int
const (
invalidKind kind = iota
boolKind
complexKind
intKind
floatKind
integerKind
stringKind
uintKind
)
func basicKind(v reflect.Value) (kind, error) {
switch v.Kind() {
case reflect.Bool:
return boolKind, nil
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return intKind, nil
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return uintKind, nil
case reflect.Float32, reflect.Float64:
return floatKind, nil
case reflect.Complex64, reflect.Complex128:
return complexKind, nil
case reflect.String:
return stringKind, nil
}
return invalidKind, errBadComparisonType
}
// eq evaluates the comparison a == b || a == c || ...
func eq(arg1 interface{}, arg2 ...interface{}) (bool, error) {
v1 := reflect.ValueOf(arg1)
k1, err := basicKind(v1)
if err != nil {
return false, err
}
if len(arg2) == 0 {
return false, errNoComparison
}
for _, arg := range arg2 {
v2 := reflect.ValueOf(arg)
k2, err := basicKind(v2)
if err != nil {
return false, err
}
truth := false
if k1 != k2 {
// Special case: Can compare integer values regardless of type's sign.
switch {
case k1 == intKind && k2 == uintKind:
truth = v1.Int() >= 0 && uint64(v1.Int()) == v2.Uint()
case k1 == uintKind && k2 == intKind:
truth = v2.Int() >= 0 && v1.Uint() == uint64(v2.Int())
default:
return false, errBadComparison
}
} else {
switch k1 {
case boolKind:
truth = v1.Bool() == v2.Bool()
case complexKind:
truth = v1.Complex() == v2.Complex()
case floatKind:
truth = v1.Float() == v2.Float()
case intKind:
truth = v1.Int() == v2.Int()
case stringKind:
truth = v1.String() == v2.String()
case uintKind:
truth = v1.Uint() == v2.Uint()
default:
panic("invalid kind")
}
}
if truth {
return true, nil
}
}
return false, nil
}
// ne evaluates the comparison a != b.
func ne(arg1, arg2 interface{}) (bool, error) {
// != is the inverse of ==.
equal, err := eq(arg1, arg2)
return !equal, err
}
// lt evaluates the comparison a < b.
func lt(arg1, arg2 interface{}) (bool, error) {
v1 := reflect.ValueOf(arg1)
k1, err := basicKind(v1)
if err != nil {
return false, err
}
v2 := reflect.ValueOf(arg2)
k2, err := basicKind(v2)
if err != nil {
return false, err
}
truth := false
if k1 != k2 {
// Special case: Can compare integer values regardless of type's sign.
switch {
case k1 == intKind && k2 == uintKind:
truth = v1.Int() < 0 || uint64(v1.Int()) < v2.Uint()
case k1 == uintKind && k2 == intKind:
truth = v2.Int() >= 0 && v1.Uint() < uint64(v2.Int())
default:
return false, errBadComparison
}
} else {
switch k1 {
case boolKind, complexKind:
return false, errBadComparisonType
case floatKind:
truth = v1.Float() < v2.Float()
case intKind:
truth = v1.Int() < v2.Int()
case stringKind:
truth = v1.String() < v2.String()
case uintKind:
truth = v1.Uint() < v2.Uint()
default:
panic("invalid kind")
}
}
return truth, nil
}
// le evaluates the comparison <= b.
func le(arg1, arg2 interface{}) (bool, error) {
// <= is < or ==.
lessThan, err := lt(arg1, arg2)
if lessThan || err != nil {
return lessThan, err
}
return eq(arg1, arg2)
}
// gt evaluates the comparison a > b.
func gt(arg1, arg2 interface{}) (bool, error) {
// > is the inverse of <=.
lessOrEqual, err := le(arg1, arg2)
if err != nil {
return false, err
}
return !lessOrEqual, nil
}
// ge evaluates the comparison a >= b.
func ge(arg1, arg2 interface{}) (bool, error) {
// >= is the inverse of <.
lessThan, err := lt(arg1, arg2)
if err != nil {
return false, err
}
return !lessThan, nil
}
// HTML escaping.
var (
htmlQuot = []byte("&#34;") // shorter than "&quot;"
htmlApos = []byte("&#39;") // shorter than "&apos;" and apos was not in HTML until HTML5
htmlAmp = []byte("&amp;")
htmlLt = []byte("&lt;")
htmlGt = []byte("&gt;")
)
// HTMLEscape writes to w the escaped HTML equivalent of the plain text data b.
func HTMLEscape(w io.Writer, b []byte) {
last := 0
for i, c := range b {
var html []byte
switch c {
case '"':
html = htmlQuot
case '\'':
html = htmlApos
case '&':
html = htmlAmp
case '<':
html = htmlLt
case '>':
html = htmlGt
default:
continue
}
w.Write(b[last:i])
w.Write(html)
last = i + 1
}
w.Write(b[last:])
}
// HTMLEscapeString returns the escaped HTML equivalent of the plain text data s.
func HTMLEscapeString(s string) string {
// Avoid allocation if we can.
if strings.IndexAny(s, `'"&<>`) < 0 {
return s
}
var b bytes.Buffer
HTMLEscape(&b, []byte(s))
return b.String()
}
// HTMLEscaper returns the escaped HTML equivalent of the textual
// representation of its arguments.
func HTMLEscaper(args ...interface{}) string {
return HTMLEscapeString(evalArgs(args))
}
// JavaScript escaping.
var (
jsLowUni = []byte(`\u00`)
hex = []byte("0123456789ABCDEF")
jsBackslash = []byte(`\\`)
jsApos = []byte(`\'`)
jsQuot = []byte(`\"`)
jsLt = []byte(`\x3C`)
jsGt = []byte(`\x3E`)
)
// JSEscape writes to w the escaped JavaScript equivalent of the plain text data b.
func JSEscape(w io.Writer, b []byte) {
last := 0
for i := 0; i < len(b); i++ {
c := b[i]
if !jsIsSpecial(rune(c)) {
// fast path: nothing to do
continue
}
w.Write(b[last:i])
if c < utf8.RuneSelf {
// Quotes, slashes and angle brackets get quoted.
// Control characters get written as \u00XX.
switch c {
case '\\':
w.Write(jsBackslash)
case '\'':
w.Write(jsApos)
case '"':
w.Write(jsQuot)
case '<':
w.Write(jsLt)
case '>':
w.Write(jsGt)
default:
w.Write(jsLowUni)
t, b := c>>4, c&0x0f
w.Write(hex[t : t+1])
w.Write(hex[b : b+1])
}
} else {
// Unicode rune.
r, size := utf8.DecodeRune(b[i:])
if unicode.IsPrint(r) {
w.Write(b[i : i+size])
} else {
fmt.Fprintf(w, "\\u%04X", r)
}
i += size - 1
}
last = i + 1
}
w.Write(b[last:])
}
// JSEscapeString returns the escaped JavaScript equivalent of the plain text data s.
func JSEscapeString(s string) string {
// Avoid allocation if we can.
if strings.IndexFunc(s, jsIsSpecial) < 0 {
return s
}
var b bytes.Buffer
JSEscape(&b, []byte(s))
return b.String()
}
func jsIsSpecial(r rune) bool {
switch r {
case '\\', '\'', '"', '<', '>':
return true
}
return r < ' ' || utf8.RuneSelf <= r
}
// JSEscaper returns the escaped JavaScript equivalent of the textual
// representation of its arguments.
func JSEscaper(args ...interface{}) string {
return JSEscapeString(evalArgs(args))
}
// URLQueryEscaper returns the escaped value of the textual representation of
// its arguments in a form suitable for embedding in a URL query.
func URLQueryEscaper(args ...interface{}) string {
return url.QueryEscape(evalArgs(args))
}
// evalArgs formats the list of arguments into a string. It is therefore equivalent to
// fmt.Sprint(args...)
// except that each argument is indirected (if a pointer), as required,
// using the same rules as the default string evaluation during template
// execution.
func evalArgs(args []interface{}) string {
ok := false
var s string
// Fast path for simple common case.
if len(args) == 1 {
s, ok = args[0].(string)
}
if !ok {
for i, arg := range args {
a, ok := printableValue(reflect.ValueOf(arg))
if ok {
args[i] = a
} // else left fmt do its thing
}
s = fmt.Sprint(args...)
}
return s
}

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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Helper functions to make constructing templates easier.
package template
import (
"fmt"
"io/ioutil"
"path/filepath"
)
// Functions and methods to parse templates.
// Must is a helper that wraps a call to a function returning (*Template, error)
// and panics if the error is non-nil. It is intended for use in variable
// initializations such as
// var t = template.Must(template.New("name").Parse("text"))
func Must(t *Template, err error) *Template {
if err != nil {
panic(err)
}
return t
}
// ParseFiles creates a new Template and parses the template definitions from
// the named files. The returned template's name will have the (base) name and
// (parsed) contents of the first file. There must be at least one file.
// If an error occurs, parsing stops and the returned *Template is nil.
func ParseFiles(filenames ...string) (*Template, error) {
return parseFiles(nil, filenames...)
}
// ParseFiles parses the named files and associates the resulting templates with
// t. If an error occurs, parsing stops and the returned template is nil;
// otherwise it is t. There must be at least one file.
func (t *Template) ParseFiles(filenames ...string) (*Template, error) {
return parseFiles(t, filenames...)
}
// parseFiles is the helper for the method and function. If the argument
// template is nil, it is created from the first file.
func parseFiles(t *Template, filenames ...string) (*Template, error) {
if len(filenames) == 0 {
// Not really a problem, but be consistent.
return nil, fmt.Errorf("template: no files named in call to ParseFiles")
}
for _, filename := range filenames {
b, err := ioutil.ReadFile(filename)
if err != nil {
return nil, err
}
s := string(b)
name := filepath.Base(filename)
// First template becomes return value if not already defined,
// and we use that one for subsequent New calls to associate
// all the templates together. Also, if this file has the same name
// as t, this file becomes the contents of t, so
// t, err := New(name).Funcs(xxx).ParseFiles(name)
// works. Otherwise we create a new template associated with t.
var tmpl *Template
if t == nil {
t = New(name)
}
if name == t.Name() {
tmpl = t
} else {
tmpl = t.New(name)
}
_, err = tmpl.Parse(s)
if err != nil {
return nil, err
}
}
return t, nil
}
// ParseGlob creates a new Template and parses the template definitions from the
// files identified by the pattern, which must match at least one file. The
// returned template will have the (base) name and (parsed) contents of the
// first file matched by the pattern. ParseGlob is equivalent to calling
// ParseFiles with the list of files matched by the pattern.
func ParseGlob(pattern string) (*Template, error) {
return parseGlob(nil, pattern)
}
// ParseGlob parses the template definitions in the files identified by the
// pattern and associates the resulting templates with t. The pattern is
// processed by filepath.Glob and must match at least one file. ParseGlob is
// equivalent to calling t.ParseFiles with the list of files matched by the
// pattern.
func (t *Template) ParseGlob(pattern string) (*Template, error) {
return parseGlob(t, pattern)
}
// parseGlob is the implementation of the function and method ParseGlob.
func parseGlob(t *Template, pattern string) (*Template, error) {
filenames, err := filepath.Glob(pattern)
if err != nil {
return nil, err
}
if len(filenames) == 0 {
return nil, fmt.Errorf("template: pattern matches no files: %#q", pattern)
}
return parseFiles(t, filenames...)
}

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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package template
// Tests for mulitple-template parsing and execution.
import (
"bytes"
"fmt"
"github.com/alecthomas/template/parse"
"strings"
"testing"
)
const (
noError = true
hasError = false
)
type multiParseTest struct {
name string
input string
ok bool
names []string
results []string
}
var multiParseTests = []multiParseTest{
{"empty", "", noError,
nil,
nil},
{"one", `{{define "foo"}} FOO {{end}}`, noError,
[]string{"foo"},
[]string{" FOO "}},
{"two", `{{define "foo"}} FOO {{end}}{{define "bar"}} BAR {{end}}`, noError,
[]string{"foo", "bar"},
[]string{" FOO ", " BAR "}},
// errors
{"missing end", `{{define "foo"}} FOO `, hasError,
nil,
nil},
{"malformed name", `{{define "foo}} FOO `, hasError,
nil,
nil},
}
func TestMultiParse(t *testing.T) {
for _, test := range multiParseTests {
template, err := New("root").Parse(test.input)
switch {
case err == nil && !test.ok:
t.Errorf("%q: expected error; got none", test.name)
continue
case err != nil && test.ok:
t.Errorf("%q: unexpected error: %v", test.name, err)
continue
case err != nil && !test.ok:
// expected error, got one
if *debug {
fmt.Printf("%s: %s\n\t%s\n", test.name, test.input, err)
}
continue
}
if template == nil {
continue
}
if len(template.tmpl) != len(test.names)+1 { // +1 for root
t.Errorf("%s: wrong number of templates; wanted %d got %d", test.name, len(test.names), len(template.tmpl))
continue
}
for i, name := range test.names {
tmpl, ok := template.tmpl[name]
if !ok {
t.Errorf("%s: can't find template %q", test.name, name)
continue
}
result := tmpl.Root.String()
if result != test.results[i] {
t.Errorf("%s=(%q): got\n\t%v\nexpected\n\t%v", test.name, test.input, result, test.results[i])
}
}
}
}
var multiExecTests = []execTest{
{"empty", "", "", nil, true},
{"text", "some text", "some text", nil, true},
{"invoke x", `{{template "x" .SI}}`, "TEXT", tVal, true},
{"invoke x no args", `{{template "x"}}`, "TEXT", tVal, true},
{"invoke dot int", `{{template "dot" .I}}`, "17", tVal, true},
{"invoke dot []int", `{{template "dot" .SI}}`, "[3 4 5]", tVal, true},
{"invoke dotV", `{{template "dotV" .U}}`, "v", tVal, true},
{"invoke nested int", `{{template "nested" .I}}`, "17", tVal, true},
{"variable declared by template", `{{template "nested" $x:=.SI}},{{index $x 1}}`, "[3 4 5],4", tVal, true},
// User-defined function: test argument evaluator.
{"testFunc literal", `{{oneArg "joe"}}`, "oneArg=joe", tVal, true},
{"testFunc .", `{{oneArg .}}`, "oneArg=joe", "joe", true},
}
// These strings are also in testdata/*.
const multiText1 = `
{{define "x"}}TEXT{{end}}
{{define "dotV"}}{{.V}}{{end}}
`
const multiText2 = `
{{define "dot"}}{{.}}{{end}}
{{define "nested"}}{{template "dot" .}}{{end}}
`
func TestMultiExecute(t *testing.T) {
// Declare a couple of templates first.
template, err := New("root").Parse(multiText1)
if err != nil {
t.Fatalf("parse error for 1: %s", err)
}
_, err = template.Parse(multiText2)
if err != nil {
t.Fatalf("parse error for 2: %s", err)
}
testExecute(multiExecTests, template, t)
}
func TestParseFiles(t *testing.T) {
_, err := ParseFiles("DOES NOT EXIST")
if err == nil {
t.Error("expected error for non-existent file; got none")
}
template := New("root")
_, err = template.ParseFiles("testdata/file1.tmpl", "testdata/file2.tmpl")
if err != nil {
t.Fatalf("error parsing files: %v", err)
}
testExecute(multiExecTests, template, t)
}
func TestParseGlob(t *testing.T) {
_, err := ParseGlob("DOES NOT EXIST")
if err == nil {
t.Error("expected error for non-existent file; got none")
}
_, err = New("error").ParseGlob("[x")
if err == nil {
t.Error("expected error for bad pattern; got none")
}
template := New("root")
_, err = template.ParseGlob("testdata/file*.tmpl")
if err != nil {
t.Fatalf("error parsing files: %v", err)
}
testExecute(multiExecTests, template, t)
}
// In these tests, actual content (not just template definitions) comes from the parsed files.
var templateFileExecTests = []execTest{
{"test", `{{template "tmpl1.tmpl"}}{{template "tmpl2.tmpl"}}`, "template1\n\ny\ntemplate2\n\nx\n", 0, true},
}
func TestParseFilesWithData(t *testing.T) {
template, err := New("root").ParseFiles("testdata/tmpl1.tmpl", "testdata/tmpl2.tmpl")
if err != nil {
t.Fatalf("error parsing files: %v", err)
}
testExecute(templateFileExecTests, template, t)
}
func TestParseGlobWithData(t *testing.T) {
template, err := New("root").ParseGlob("testdata/tmpl*.tmpl")
if err != nil {
t.Fatalf("error parsing files: %v", err)
}
testExecute(templateFileExecTests, template, t)
}
const (
cloneText1 = `{{define "a"}}{{template "b"}}{{template "c"}}{{end}}`
cloneText2 = `{{define "b"}}b{{end}}`
cloneText3 = `{{define "c"}}root{{end}}`
cloneText4 = `{{define "c"}}clone{{end}}`
)
func TestClone(t *testing.T) {
// Create some templates and clone the root.
root, err := New("root").Parse(cloneText1)
if err != nil {
t.Fatal(err)
}
_, err = root.Parse(cloneText2)
if err != nil {
t.Fatal(err)
}
clone := Must(root.Clone())
// Add variants to both.
_, err = root.Parse(cloneText3)
if err != nil {
t.Fatal(err)
}
_, err = clone.Parse(cloneText4)
if err != nil {
t.Fatal(err)
}
// Verify that the clone is self-consistent.
for k, v := range clone.tmpl {
if k == clone.name && v.tmpl[k] != clone {
t.Error("clone does not contain root")
}
if v != v.tmpl[v.name] {
t.Errorf("clone does not contain self for %q", k)
}
}
// Execute root.
var b bytes.Buffer
err = root.ExecuteTemplate(&b, "a", 0)
if err != nil {
t.Fatal(err)
}
if b.String() != "broot" {
t.Errorf("expected %q got %q", "broot", b.String())
}
// Execute copy.
b.Reset()
err = clone.ExecuteTemplate(&b, "a", 0)
if err != nil {
t.Fatal(err)
}
if b.String() != "bclone" {
t.Errorf("expected %q got %q", "bclone", b.String())
}
}
func TestAddParseTree(t *testing.T) {
// Create some templates.
root, err := New("root").Parse(cloneText1)
if err != nil {
t.Fatal(err)
}
_, err = root.Parse(cloneText2)
if err != nil {
t.Fatal(err)
}
// Add a new parse tree.
tree, err := parse.Parse("cloneText3", cloneText3, "", "", nil, builtins)
if err != nil {
t.Fatal(err)
}
added, err := root.AddParseTree("c", tree["c"])
// Execute.
var b bytes.Buffer
err = added.ExecuteTemplate(&b, "a", 0)
if err != nil {
t.Fatal(err)
}
if b.String() != "broot" {
t.Errorf("expected %q got %q", "broot", b.String())
}
}
// Issue 7032
func TestAddParseTreeToUnparsedTemplate(t *testing.T) {
master := "{{define \"master\"}}{{end}}"
tmpl := New("master")
tree, err := parse.Parse("master", master, "", "", nil)
if err != nil {
t.Fatalf("unexpected parse err: %v", err)
}
masterTree := tree["master"]
tmpl.AddParseTree("master", masterTree) // used to panic
}
func TestRedefinition(t *testing.T) {
var tmpl *Template
var err error
if tmpl, err = New("tmpl1").Parse(`{{define "test"}}foo{{end}}`); err != nil {
t.Fatalf("parse 1: %v", err)
}
if _, err = tmpl.Parse(`{{define "test"}}bar{{end}}`); err == nil {
t.Fatal("expected error")
}
if !strings.Contains(err.Error(), "redefinition") {
t.Fatalf("expected redefinition error; got %v", err)
}
if _, err = tmpl.New("tmpl2").Parse(`{{define "test"}}bar{{end}}`); err == nil {
t.Fatal("expected error")
}
if !strings.Contains(err.Error(), "redefinition") {
t.Fatalf("expected redefinition error; got %v", err)
}
}

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@ -0,0 +1,556 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package parse
import (
"fmt"
"strings"
"unicode"
"unicode/utf8"
)
// item represents a token or text string returned from the scanner.
type item struct {
typ itemType // The type of this item.
pos Pos // The starting position, in bytes, of this item in the input string.
val string // The value of this item.
}
func (i item) String() string {
switch {
case i.typ == itemEOF:
return "EOF"
case i.typ == itemError:
return i.val
case i.typ > itemKeyword:
return fmt.Sprintf("<%s>", i.val)
case len(i.val) > 10:
return fmt.Sprintf("%.10q...", i.val)
}
return fmt.Sprintf("%q", i.val)
}
// itemType identifies the type of lex items.
type itemType int
const (
itemError itemType = iota // error occurred; value is text of error
itemBool // boolean constant
itemChar // printable ASCII character; grab bag for comma etc.
itemCharConstant // character constant
itemComplex // complex constant (1+2i); imaginary is just a number
itemColonEquals // colon-equals (':=') introducing a declaration
itemEOF
itemField // alphanumeric identifier starting with '.'
itemIdentifier // alphanumeric identifier not starting with '.'
itemLeftDelim // left action delimiter
itemLeftParen // '(' inside action
itemNumber // simple number, including imaginary
itemPipe // pipe symbol
itemRawString // raw quoted string (includes quotes)
itemRightDelim // right action delimiter
itemElideNewline // elide newline after right delim
itemRightParen // ')' inside action
itemSpace // run of spaces separating arguments
itemString // quoted string (includes quotes)
itemText // plain text
itemVariable // variable starting with '$', such as '$' or '$1' or '$hello'
// Keywords appear after all the rest.
itemKeyword // used only to delimit the keywords
itemDot // the cursor, spelled '.'
itemDefine // define keyword
itemElse // else keyword
itemEnd // end keyword
itemIf // if keyword
itemNil // the untyped nil constant, easiest to treat as a keyword
itemRange // range keyword
itemTemplate // template keyword
itemWith // with keyword
)
var key = map[string]itemType{
".": itemDot,
"define": itemDefine,
"else": itemElse,
"end": itemEnd,
"if": itemIf,
"range": itemRange,
"nil": itemNil,
"template": itemTemplate,
"with": itemWith,
}
const eof = -1
// stateFn represents the state of the scanner as a function that returns the next state.
type stateFn func(*lexer) stateFn
// lexer holds the state of the scanner.
type lexer struct {
name string // the name of the input; used only for error reports
input string // the string being scanned
leftDelim string // start of action
rightDelim string // end of action
state stateFn // the next lexing function to enter
pos Pos // current position in the input
start Pos // start position of this item
width Pos // width of last rune read from input
lastPos Pos // position of most recent item returned by nextItem
items chan item // channel of scanned items
parenDepth int // nesting depth of ( ) exprs
}
// next returns the next rune in the input.
func (l *lexer) next() rune {
if int(l.pos) >= len(l.input) {
l.width = 0
return eof
}
r, w := utf8.DecodeRuneInString(l.input[l.pos:])
l.width = Pos(w)
l.pos += l.width
return r
}
// peek returns but does not consume the next rune in the input.
func (l *lexer) peek() rune {
r := l.next()
l.backup()
return r
}
// backup steps back one rune. Can only be called once per call of next.
func (l *lexer) backup() {
l.pos -= l.width
}
// emit passes an item back to the client.
func (l *lexer) emit(t itemType) {
l.items <- item{t, l.start, l.input[l.start:l.pos]}
l.start = l.pos
}
// ignore skips over the pending input before this point.
func (l *lexer) ignore() {
l.start = l.pos
}
// accept consumes the next rune if it's from the valid set.
func (l *lexer) accept(valid string) bool {
if strings.IndexRune(valid, l.next()) >= 0 {
return true
}
l.backup()
return false
}
// acceptRun consumes a run of runes from the valid set.
func (l *lexer) acceptRun(valid string) {
for strings.IndexRune(valid, l.next()) >= 0 {
}
l.backup()
}
// lineNumber reports which line we're on, based on the position of
// the previous item returned by nextItem. Doing it this way
// means we don't have to worry about peek double counting.
func (l *lexer) lineNumber() int {
return 1 + strings.Count(l.input[:l.lastPos], "\n")
}
// errorf returns an error token and terminates the scan by passing
// back a nil pointer that will be the next state, terminating l.nextItem.
func (l *lexer) errorf(format string, args ...interface{}) stateFn {
l.items <- item{itemError, l.start, fmt.Sprintf(format, args...)}
return nil
}
// nextItem returns the next item from the input.
func (l *lexer) nextItem() item {
item := <-l.items
l.lastPos = item.pos
return item
}
// lex creates a new scanner for the input string.
func lex(name, input, left, right string) *lexer {
if left == "" {
left = leftDelim
}
if right == "" {
right = rightDelim
}
l := &lexer{
name: name,
input: input,
leftDelim: left,
rightDelim: right,
items: make(chan item),
}
go l.run()
return l
}
// run runs the state machine for the lexer.
func (l *lexer) run() {
for l.state = lexText; l.state != nil; {
l.state = l.state(l)
}
}
// state functions
const (
leftDelim = "{{"
rightDelim = "}}"
leftComment = "/*"
rightComment = "*/"
)
// lexText scans until an opening action delimiter, "{{".
func lexText(l *lexer) stateFn {
for {
if strings.HasPrefix(l.input[l.pos:], l.leftDelim) {
if l.pos > l.start {
l.emit(itemText)
}
return lexLeftDelim
}
if l.next() == eof {
break
}
}
// Correctly reached EOF.
if l.pos > l.start {
l.emit(itemText)
}
l.emit(itemEOF)
return nil
}
// lexLeftDelim scans the left delimiter, which is known to be present.
func lexLeftDelim(l *lexer) stateFn {
l.pos += Pos(len(l.leftDelim))
if strings.HasPrefix(l.input[l.pos:], leftComment) {
return lexComment
}
l.emit(itemLeftDelim)
l.parenDepth = 0
return lexInsideAction
}
// lexComment scans a comment. The left comment marker is known to be present.
func lexComment(l *lexer) stateFn {
l.pos += Pos(len(leftComment))
i := strings.Index(l.input[l.pos:], rightComment)
if i < 0 {
return l.errorf("unclosed comment")
}
l.pos += Pos(i + len(rightComment))
if !strings.HasPrefix(l.input[l.pos:], l.rightDelim) {
return l.errorf("comment ends before closing delimiter")
}
l.pos += Pos(len(l.rightDelim))
l.ignore()
return lexText
}
// lexRightDelim scans the right delimiter, which is known to be present.
func lexRightDelim(l *lexer) stateFn {
l.pos += Pos(len(l.rightDelim))
l.emit(itemRightDelim)
if l.peek() == '\\' {
l.pos++
l.emit(itemElideNewline)
}
return lexText
}
// lexInsideAction scans the elements inside action delimiters.
func lexInsideAction(l *lexer) stateFn {
// Either number, quoted string, or identifier.
// Spaces separate arguments; runs of spaces turn into itemSpace.
// Pipe symbols separate and are emitted.
if strings.HasPrefix(l.input[l.pos:], l.rightDelim+"\\") || strings.HasPrefix(l.input[l.pos:], l.rightDelim) {
if l.parenDepth == 0 {
return lexRightDelim
}
return l.errorf("unclosed left paren")
}
switch r := l.next(); {
case r == eof || isEndOfLine(r):
return l.errorf("unclosed action")
case isSpace(r):
return lexSpace
case r == ':':
if l.next() != '=' {
return l.errorf("expected :=")
}
l.emit(itemColonEquals)
case r == '|':
l.emit(itemPipe)
case r == '"':
return lexQuote
case r == '`':
return lexRawQuote
case r == '$':
return lexVariable
case r == '\'':
return lexChar
case r == '.':
// special look-ahead for ".field" so we don't break l.backup().
if l.pos < Pos(len(l.input)) {
r := l.input[l.pos]
if r < '0' || '9' < r {
return lexField
}
}
fallthrough // '.' can start a number.
case r == '+' || r == '-' || ('0' <= r && r <= '9'):
l.backup()
return lexNumber
case isAlphaNumeric(r):
l.backup()
return lexIdentifier
case r == '(':
l.emit(itemLeftParen)
l.parenDepth++
return lexInsideAction
case r == ')':
l.emit(itemRightParen)
l.parenDepth--
if l.parenDepth < 0 {
return l.errorf("unexpected right paren %#U", r)
}
return lexInsideAction
case r <= unicode.MaxASCII && unicode.IsPrint(r):
l.emit(itemChar)
return lexInsideAction
default:
return l.errorf("unrecognized character in action: %#U", r)
}
return lexInsideAction
}
// lexSpace scans a run of space characters.
// One space has already been seen.
func lexSpace(l *lexer) stateFn {
for isSpace(l.peek()) {
l.next()
}
l.emit(itemSpace)
return lexInsideAction
}
// lexIdentifier scans an alphanumeric.
func lexIdentifier(l *lexer) stateFn {
Loop:
for {
switch r := l.next(); {
case isAlphaNumeric(r):
// absorb.
default:
l.backup()
word := l.input[l.start:l.pos]
if !l.atTerminator() {
return l.errorf("bad character %#U", r)
}
switch {
case key[word] > itemKeyword:
l.emit(key[word])
case word[0] == '.':
l.emit(itemField)
case word == "true", word == "false":
l.emit(itemBool)
default:
l.emit(itemIdentifier)
}
break Loop
}
}
return lexInsideAction
}
// lexField scans a field: .Alphanumeric.
// The . has been scanned.
func lexField(l *lexer) stateFn {
return lexFieldOrVariable(l, itemField)
}
// lexVariable scans a Variable: $Alphanumeric.
// The $ has been scanned.
func lexVariable(l *lexer) stateFn {
if l.atTerminator() { // Nothing interesting follows -> "$".
l.emit(itemVariable)
return lexInsideAction
}
return lexFieldOrVariable(l, itemVariable)
}
// lexVariable scans a field or variable: [.$]Alphanumeric.
// The . or $ has been scanned.
func lexFieldOrVariable(l *lexer, typ itemType) stateFn {
if l.atTerminator() { // Nothing interesting follows -> "." or "$".
if typ == itemVariable {
l.emit(itemVariable)
} else {
l.emit(itemDot)
}
return lexInsideAction
}
var r rune
for {
r = l.next()
if !isAlphaNumeric(r) {
l.backup()
break
}
}
if !l.atTerminator() {
return l.errorf("bad character %#U", r)
}
l.emit(typ)
return lexInsideAction
}
// atTerminator reports whether the input is at valid termination character to
// appear after an identifier. Breaks .X.Y into two pieces. Also catches cases
// like "$x+2" not being acceptable without a space, in case we decide one
// day to implement arithmetic.
func (l *lexer) atTerminator() bool {
r := l.peek()
if isSpace(r) || isEndOfLine(r) {
return true
}
switch r {
case eof, '.', ',', '|', ':', ')', '(':
return true
}
// Does r start the delimiter? This can be ambiguous (with delim=="//", $x/2 will
// succeed but should fail) but only in extremely rare cases caused by willfully
// bad choice of delimiter.
if rd, _ := utf8.DecodeRuneInString(l.rightDelim); rd == r {
return true
}
return false
}
// lexChar scans a character constant. The initial quote is already
// scanned. Syntax checking is done by the parser.
func lexChar(l *lexer) stateFn {
Loop:
for {
switch l.next() {
case '\\':
if r := l.next(); r != eof && r != '\n' {
break
}
fallthrough
case eof, '\n':
return l.errorf("unterminated character constant")
case '\'':
break Loop
}
}
l.emit(itemCharConstant)
return lexInsideAction
}
// lexNumber scans a number: decimal, octal, hex, float, or imaginary. This
// isn't a perfect number scanner - for instance it accepts "." and "0x0.2"
// and "089" - but when it's wrong the input is invalid and the parser (via
// strconv) will notice.
func lexNumber(l *lexer) stateFn {
if !l.scanNumber() {
return l.errorf("bad number syntax: %q", l.input[l.start:l.pos])
}
if sign := l.peek(); sign == '+' || sign == '-' {
// Complex: 1+2i. No spaces, must end in 'i'.
if !l.scanNumber() || l.input[l.pos-1] != 'i' {
return l.errorf("bad number syntax: %q", l.input[l.start:l.pos])
}
l.emit(itemComplex)
} else {
l.emit(itemNumber)
}
return lexInsideAction
}
func (l *lexer) scanNumber() bool {
// Optional leading sign.
l.accept("+-")
// Is it hex?
digits := "0123456789"
if l.accept("0") && l.accept("xX") {
digits = "0123456789abcdefABCDEF"
}
l.acceptRun(digits)
if l.accept(".") {
l.acceptRun(digits)
}
if l.accept("eE") {
l.accept("+-")
l.acceptRun("0123456789")
}
// Is it imaginary?
l.accept("i")
// Next thing mustn't be alphanumeric.
if isAlphaNumeric(l.peek()) {
l.next()
return false
}
return true
}
// lexQuote scans a quoted string.
func lexQuote(l *lexer) stateFn {
Loop:
for {
switch l.next() {
case '\\':
if r := l.next(); r != eof && r != '\n' {
break
}
fallthrough
case eof, '\n':
return l.errorf("unterminated quoted string")
case '"':
break Loop
}
}
l.emit(itemString)
return lexInsideAction
}
// lexRawQuote scans a raw quoted string.
func lexRawQuote(l *lexer) stateFn {
Loop:
for {
switch l.next() {
case eof, '\n':
return l.errorf("unterminated raw quoted string")
case '`':
break Loop
}
}
l.emit(itemRawString)
return lexInsideAction
}
// isSpace reports whether r is a space character.
func isSpace(r rune) bool {
return r == ' ' || r == '\t'
}
// isEndOfLine reports whether r is an end-of-line character.
func isEndOfLine(r rune) bool {
return r == '\r' || r == '\n'
}
// isAlphaNumeric reports whether r is an alphabetic, digit, or underscore.
func isAlphaNumeric(r rune) bool {
return r == '_' || unicode.IsLetter(r) || unicode.IsDigit(r)
}

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@ -0,0 +1,468 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package parse
import (
"fmt"
"testing"
)
// Make the types prettyprint.
var itemName = map[itemType]string{
itemError: "error",
itemBool: "bool",
itemChar: "char",
itemCharConstant: "charconst",
itemComplex: "complex",
itemColonEquals: ":=",
itemEOF: "EOF",
itemField: "field",
itemIdentifier: "identifier",
itemLeftDelim: "left delim",
itemLeftParen: "(",
itemNumber: "number",
itemPipe: "pipe",
itemRawString: "raw string",
itemRightDelim: "right delim",
itemElideNewline: "elide newline",
itemRightParen: ")",
itemSpace: "space",
itemString: "string",
itemVariable: "variable",
// keywords
itemDot: ".",
itemDefine: "define",
itemElse: "else",
itemIf: "if",
itemEnd: "end",
itemNil: "nil",
itemRange: "range",
itemTemplate: "template",
itemWith: "with",
}
func (i itemType) String() string {
s := itemName[i]
if s == "" {
return fmt.Sprintf("item%d", int(i))
}
return s
}
type lexTest struct {
name string
input string
items []item
}
var (
tEOF = item{itemEOF, 0, ""}
tFor = item{itemIdentifier, 0, "for"}
tLeft = item{itemLeftDelim, 0, "{{"}
tLpar = item{itemLeftParen, 0, "("}
tPipe = item{itemPipe, 0, "|"}
tQuote = item{itemString, 0, `"abc \n\t\" "`}
tRange = item{itemRange, 0, "range"}
tRight = item{itemRightDelim, 0, "}}"}
tElideNewline = item{itemElideNewline, 0, "\\"}
tRpar = item{itemRightParen, 0, ")"}
tSpace = item{itemSpace, 0, " "}
raw = "`" + `abc\n\t\" ` + "`"
tRawQuote = item{itemRawString, 0, raw}
)
var lexTests = []lexTest{
{"empty", "", []item{tEOF}},
{"spaces", " \t\n", []item{{itemText, 0, " \t\n"}, tEOF}},
{"text", `now is the time`, []item{{itemText, 0, "now is the time"}, tEOF}},
{"elide newline", "{{}}\\", []item{tLeft, tRight, tElideNewline, tEOF}},
{"text with comment", "hello-{{/* this is a comment */}}-world", []item{
{itemText, 0, "hello-"},
{itemText, 0, "-world"},
tEOF,
}},
{"punctuation", "{{,@% }}", []item{
tLeft,
{itemChar, 0, ","},
{itemChar, 0, "@"},
{itemChar, 0, "%"},
tSpace,
tRight,
tEOF,
}},
{"parens", "{{((3))}}", []item{
tLeft,
tLpar,
tLpar,
{itemNumber, 0, "3"},
tRpar,
tRpar,
tRight,
tEOF,
}},
{"empty action", `{{}}`, []item{tLeft, tRight, tEOF}},
{"for", `{{for}}`, []item{tLeft, tFor, tRight, tEOF}},
{"quote", `{{"abc \n\t\" "}}`, []item{tLeft, tQuote, tRight, tEOF}},
{"raw quote", "{{" + raw + "}}", []item{tLeft, tRawQuote, tRight, tEOF}},
{"numbers", "{{1 02 0x14 -7.2i 1e3 +1.2e-4 4.2i 1+2i}}", []item{
tLeft,
{itemNumber, 0, "1"},
tSpace,
{itemNumber, 0, "02"},
tSpace,
{itemNumber, 0, "0x14"},
tSpace,
{itemNumber, 0, "-7.2i"},
tSpace,
{itemNumber, 0, "1e3"},
tSpace,
{itemNumber, 0, "+1.2e-4"},
tSpace,
{itemNumber, 0, "4.2i"},
tSpace,
{itemComplex, 0, "1+2i"},
tRight,
tEOF,
}},
{"characters", `{{'a' '\n' '\'' '\\' '\u00FF' '\xFF' '本'}}`, []item{
tLeft,
{itemCharConstant, 0, `'a'`},
tSpace,
{itemCharConstant, 0, `'\n'`},
tSpace,
{itemCharConstant, 0, `'\''`},
tSpace,
{itemCharConstant, 0, `'\\'`},
tSpace,
{itemCharConstant, 0, `'\u00FF'`},
tSpace,
{itemCharConstant, 0, `'\xFF'`},
tSpace,
{itemCharConstant, 0, `'本'`},
tRight,
tEOF,
}},
{"bools", "{{true false}}", []item{
tLeft,
{itemBool, 0, "true"},
tSpace,
{itemBool, 0, "false"},
tRight,
tEOF,
}},
{"dot", "{{.}}", []item{
tLeft,
{itemDot, 0, "."},
tRight,
tEOF,
}},
{"nil", "{{nil}}", []item{
tLeft,
{itemNil, 0, "nil"},
tRight,
tEOF,
}},
{"dots", "{{.x . .2 .x.y.z}}", []item{
tLeft,
{itemField, 0, ".x"},
tSpace,
{itemDot, 0, "."},
tSpace,
{itemNumber, 0, ".2"},
tSpace,
{itemField, 0, ".x"},
{itemField, 0, ".y"},
{itemField, 0, ".z"},
tRight,
tEOF,
}},
{"keywords", "{{range if else end with}}", []item{
tLeft,
{itemRange, 0, "range"},
tSpace,
{itemIf, 0, "if"},
tSpace,
{itemElse, 0, "else"},
tSpace,
{itemEnd, 0, "end"},
tSpace,
{itemWith, 0, "with"},
tRight,
tEOF,
}},
{"variables", "{{$c := printf $ $hello $23 $ $var.Field .Method}}", []item{
tLeft,
{itemVariable, 0, "$c"},
tSpace,
{itemColonEquals, 0, ":="},
tSpace,
{itemIdentifier, 0, "printf"},
tSpace,
{itemVariable, 0, "$"},
tSpace,
{itemVariable, 0, "$hello"},
tSpace,
{itemVariable, 0, "$23"},
tSpace,
{itemVariable, 0, "$"},
tSpace,
{itemVariable, 0, "$var"},
{itemField, 0, ".Field"},
tSpace,
{itemField, 0, ".Method"},
tRight,
tEOF,
}},
{"variable invocation", "{{$x 23}}", []item{
tLeft,
{itemVariable, 0, "$x"},
tSpace,
{itemNumber, 0, "23"},
tRight,
tEOF,
}},
{"pipeline", `intro {{echo hi 1.2 |noargs|args 1 "hi"}} outro`, []item{
{itemText, 0, "intro "},
tLeft,
{itemIdentifier, 0, "echo"},
tSpace,
{itemIdentifier, 0, "hi"},
tSpace,
{itemNumber, 0, "1.2"},
tSpace,
tPipe,
{itemIdentifier, 0, "noargs"},
tPipe,
{itemIdentifier, 0, "args"},
tSpace,
{itemNumber, 0, "1"},
tSpace,
{itemString, 0, `"hi"`},
tRight,
{itemText, 0, " outro"},
tEOF,
}},
{"declaration", "{{$v := 3}}", []item{
tLeft,
{itemVariable, 0, "$v"},
tSpace,
{itemColonEquals, 0, ":="},
tSpace,
{itemNumber, 0, "3"},
tRight,
tEOF,
}},
{"2 declarations", "{{$v , $w := 3}}", []item{
tLeft,
{itemVariable, 0, "$v"},
tSpace,
{itemChar, 0, ","},
tSpace,
{itemVariable, 0, "$w"},
tSpace,
{itemColonEquals, 0, ":="},
tSpace,
{itemNumber, 0, "3"},
tRight,
tEOF,
}},
{"field of parenthesized expression", "{{(.X).Y}}", []item{
tLeft,
tLpar,
{itemField, 0, ".X"},
tRpar,
{itemField, 0, ".Y"},
tRight,
tEOF,
}},
// errors
{"badchar", "#{{\x01}}", []item{
{itemText, 0, "#"},
tLeft,
{itemError, 0, "unrecognized character in action: U+0001"},
}},
{"unclosed action", "{{\n}}", []item{
tLeft,
{itemError, 0, "unclosed action"},
}},
{"EOF in action", "{{range", []item{
tLeft,
tRange,
{itemError, 0, "unclosed action"},
}},
{"unclosed quote", "{{\"\n\"}}", []item{
tLeft,
{itemError, 0, "unterminated quoted string"},
}},
{"unclosed raw quote", "{{`xx\n`}}", []item{
tLeft,
{itemError, 0, "unterminated raw quoted string"},
}},
{"unclosed char constant", "{{'\n}}", []item{
tLeft,
{itemError, 0, "unterminated character constant"},
}},
{"bad number", "{{3k}}", []item{
tLeft,
{itemError, 0, `bad number syntax: "3k"`},
}},
{"unclosed paren", "{{(3}}", []item{
tLeft,
tLpar,
{itemNumber, 0, "3"},
{itemError, 0, `unclosed left paren`},
}},
{"extra right paren", "{{3)}}", []item{
tLeft,
{itemNumber, 0, "3"},
tRpar,
{itemError, 0, `unexpected right paren U+0029 ')'`},
}},
// Fixed bugs
// Many elements in an action blew the lookahead until
// we made lexInsideAction not loop.
{"long pipeline deadlock", "{{|||||}}", []item{
tLeft,
tPipe,
tPipe,
tPipe,
tPipe,
tPipe,
tRight,
tEOF,
}},
{"text with bad comment", "hello-{{/*/}}-world", []item{
{itemText, 0, "hello-"},
{itemError, 0, `unclosed comment`},
}},
{"text with comment close separted from delim", "hello-{{/* */ }}-world", []item{
{itemText, 0, "hello-"},
{itemError, 0, `comment ends before closing delimiter`},
}},
// This one is an error that we can't catch because it breaks templates with
// minimized JavaScript. Should have fixed it before Go 1.1.
{"unmatched right delimiter", "hello-{.}}-world", []item{
{itemText, 0, "hello-{.}}-world"},
tEOF,
}},
}
// collect gathers the emitted items into a slice.
func collect(t *lexTest, left, right string) (items []item) {
l := lex(t.name, t.input, left, right)
for {
item := l.nextItem()
items = append(items, item)
if item.typ == itemEOF || item.typ == itemError {
break
}
}
return
}
func equal(i1, i2 []item, checkPos bool) bool {
if len(i1) != len(i2) {
return false
}
for k := range i1 {
if i1[k].typ != i2[k].typ {
return false
}
if i1[k].val != i2[k].val {
return false
}
if checkPos && i1[k].pos != i2[k].pos {
return false
}
}
return true
}
func TestLex(t *testing.T) {
for _, test := range lexTests {
items := collect(&test, "", "")
if !equal(items, test.items, false) {
t.Errorf("%s: got\n\t%+v\nexpected\n\t%v", test.name, items, test.items)
}
}
}
// Some easy cases from above, but with delimiters $$ and @@
var lexDelimTests = []lexTest{
{"punctuation", "$$,@%{{}}@@", []item{
tLeftDelim,
{itemChar, 0, ","},
{itemChar, 0, "@"},
{itemChar, 0, "%"},
{itemChar, 0, "{"},
{itemChar, 0, "{"},
{itemChar, 0, "}"},
{itemChar, 0, "}"},
tRightDelim,
tEOF,
}},
{"empty action", `$$@@`, []item{tLeftDelim, tRightDelim, tEOF}},
{"for", `$$for@@`, []item{tLeftDelim, tFor, tRightDelim, tEOF}},
{"quote", `$$"abc \n\t\" "@@`, []item{tLeftDelim, tQuote, tRightDelim, tEOF}},
{"raw quote", "$$" + raw + "@@", []item{tLeftDelim, tRawQuote, tRightDelim, tEOF}},
}
var (
tLeftDelim = item{itemLeftDelim, 0, "$$"}
tRightDelim = item{itemRightDelim, 0, "@@"}
)
func TestDelims(t *testing.T) {
for _, test := range lexDelimTests {
items := collect(&test, "$$", "@@")
if !equal(items, test.items, false) {
t.Errorf("%s: got\n\t%v\nexpected\n\t%v", test.name, items, test.items)
}
}
}
var lexPosTests = []lexTest{
{"empty", "", []item{tEOF}},
{"punctuation", "{{,@%#}}", []item{
{itemLeftDelim, 0, "{{"},
{itemChar, 2, ","},
{itemChar, 3, "@"},
{itemChar, 4, "%"},
{itemChar, 5, "#"},
{itemRightDelim, 6, "}}"},
{itemEOF, 8, ""},
}},
{"sample", "0123{{hello}}xyz", []item{
{itemText, 0, "0123"},
{itemLeftDelim, 4, "{{"},
{itemIdentifier, 6, "hello"},
{itemRightDelim, 11, "}}"},
{itemText, 13, "xyz"},
{itemEOF, 16, ""},
}},
}
// The other tests don't check position, to make the test cases easier to construct.
// This one does.
func TestPos(t *testing.T) {
for _, test := range lexPosTests {
items := collect(&test, "", "")
if !equal(items, test.items, true) {
t.Errorf("%s: got\n\t%v\nexpected\n\t%v", test.name, items, test.items)
if len(items) == len(test.items) {
// Detailed print; avoid item.String() to expose the position value.
for i := range items {
if !equal(items[i:i+1], test.items[i:i+1], true) {
i1 := items[i]
i2 := test.items[i]
t.Errorf("\t#%d: got {%v %d %q} expected {%v %d %q}", i, i1.typ, i1.pos, i1.val, i2.typ, i2.pos, i2.val)
}
}
}
}
}
}

View file

@ -0,0 +1,834 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Parse nodes.
package parse
import (
"bytes"
"fmt"
"strconv"
"strings"
)
var textFormat = "%s" // Changed to "%q" in tests for better error messages.
// A Node is an element in the parse tree. The interface is trivial.
// The interface contains an unexported method so that only
// types local to this package can satisfy it.
type Node interface {
Type() NodeType
String() string
// Copy does a deep copy of the Node and all its components.
// To avoid type assertions, some XxxNodes also have specialized
// CopyXxx methods that return *XxxNode.
Copy() Node
Position() Pos // byte position of start of node in full original input string
// tree returns the containing *Tree.
// It is unexported so all implementations of Node are in this package.
tree() *Tree
}
// NodeType identifies the type of a parse tree node.
type NodeType int
// Pos represents a byte position in the original input text from which
// this template was parsed.
type Pos int
func (p Pos) Position() Pos {
return p
}
// Type returns itself and provides an easy default implementation
// for embedding in a Node. Embedded in all non-trivial Nodes.
func (t NodeType) Type() NodeType {
return t
}
const (
NodeText NodeType = iota // Plain text.
NodeAction // A non-control action such as a field evaluation.
NodeBool // A boolean constant.
NodeChain // A sequence of field accesses.
NodeCommand // An element of a pipeline.
NodeDot // The cursor, dot.
nodeElse // An else action. Not added to tree.
nodeEnd // An end action. Not added to tree.
NodeField // A field or method name.
NodeIdentifier // An identifier; always a function name.
NodeIf // An if action.
NodeList // A list of Nodes.
NodeNil // An untyped nil constant.
NodeNumber // A numerical constant.
NodePipe // A pipeline of commands.
NodeRange // A range action.
NodeString // A string constant.
NodeTemplate // A template invocation action.
NodeVariable // A $ variable.
NodeWith // A with action.
)
// Nodes.
// ListNode holds a sequence of nodes.
type ListNode struct {
NodeType
Pos
tr *Tree
Nodes []Node // The element nodes in lexical order.
}
func (t *Tree) newList(pos Pos) *ListNode {
return &ListNode{tr: t, NodeType: NodeList, Pos: pos}
}
func (l *ListNode) append(n Node) {
l.Nodes = append(l.Nodes, n)
}
func (l *ListNode) tree() *Tree {
return l.tr
}
func (l *ListNode) String() string {
b := new(bytes.Buffer)
for _, n := range l.Nodes {
fmt.Fprint(b, n)
}
return b.String()
}
func (l *ListNode) CopyList() *ListNode {
if l == nil {
return l
}
n := l.tr.newList(l.Pos)
for _, elem := range l.Nodes {
n.append(elem.Copy())
}
return n
}
func (l *ListNode) Copy() Node {
return l.CopyList()
}
// TextNode holds plain text.
type TextNode struct {
NodeType
Pos
tr *Tree
Text []byte // The text; may span newlines.
}
func (t *Tree) newText(pos Pos, text string) *TextNode {
return &TextNode{tr: t, NodeType: NodeText, Pos: pos, Text: []byte(text)}
}
func (t *TextNode) String() string {
return fmt.Sprintf(textFormat, t.Text)
}
func (t *TextNode) tree() *Tree {
return t.tr
}
func (t *TextNode) Copy() Node {
return &TextNode{tr: t.tr, NodeType: NodeText, Pos: t.Pos, Text: append([]byte{}, t.Text...)}
}
// PipeNode holds a pipeline with optional declaration
type PipeNode struct {
NodeType
Pos
tr *Tree
Line int // The line number in the input (deprecated; kept for compatibility)
Decl []*VariableNode // Variable declarations in lexical order.
Cmds []*CommandNode // The commands in lexical order.
}
func (t *Tree) newPipeline(pos Pos, line int, decl []*VariableNode) *PipeNode {
return &PipeNode{tr: t, NodeType: NodePipe, Pos: pos, Line: line, Decl: decl}
}
func (p *PipeNode) append(command *CommandNode) {
p.Cmds = append(p.Cmds, command)
}
func (p *PipeNode) String() string {
s := ""
if len(p.Decl) > 0 {
for i, v := range p.Decl {
if i > 0 {
s += ", "
}
s += v.String()
}
s += " := "
}
for i, c := range p.Cmds {
if i > 0 {
s += " | "
}
s += c.String()
}
return s
}
func (p *PipeNode) tree() *Tree {
return p.tr
}
func (p *PipeNode) CopyPipe() *PipeNode {
if p == nil {
return p
}
var decl []*VariableNode
for _, d := range p.Decl {
decl = append(decl, d.Copy().(*VariableNode))
}
n := p.tr.newPipeline(p.Pos, p.Line, decl)
for _, c := range p.Cmds {
n.append(c.Copy().(*CommandNode))
}
return n
}
func (p *PipeNode) Copy() Node {
return p.CopyPipe()
}
// ActionNode holds an action (something bounded by delimiters).
// Control actions have their own nodes; ActionNode represents simple
// ones such as field evaluations and parenthesized pipelines.
type ActionNode struct {
NodeType
Pos
tr *Tree
Line int // The line number in the input (deprecated; kept for compatibility)
Pipe *PipeNode // The pipeline in the action.
}
func (t *Tree) newAction(pos Pos, line int, pipe *PipeNode) *ActionNode {
return &ActionNode{tr: t, NodeType: NodeAction, Pos: pos, Line: line, Pipe: pipe}
}
func (a *ActionNode) String() string {
return fmt.Sprintf("{{%s}}", a.Pipe)
}
func (a *ActionNode) tree() *Tree {
return a.tr
}
func (a *ActionNode) Copy() Node {
return a.tr.newAction(a.Pos, a.Line, a.Pipe.CopyPipe())
}
// CommandNode holds a command (a pipeline inside an evaluating action).
type CommandNode struct {
NodeType
Pos
tr *Tree
Args []Node // Arguments in lexical order: Identifier, field, or constant.
}
func (t *Tree) newCommand(pos Pos) *CommandNode {
return &CommandNode{tr: t, NodeType: NodeCommand, Pos: pos}
}
func (c *CommandNode) append(arg Node) {
c.Args = append(c.Args, arg)
}
func (c *CommandNode) String() string {
s := ""
for i, arg := range c.Args {
if i > 0 {
s += " "
}
if arg, ok := arg.(*PipeNode); ok {
s += "(" + arg.String() + ")"
continue
}
s += arg.String()
}
return s
}
func (c *CommandNode) tree() *Tree {
return c.tr
}
func (c *CommandNode) Copy() Node {
if c == nil {
return c
}
n := c.tr.newCommand(c.Pos)
for _, c := range c.Args {
n.append(c.Copy())
}
return n
}
// IdentifierNode holds an identifier.
type IdentifierNode struct {
NodeType
Pos
tr *Tree
Ident string // The identifier's name.
}
// NewIdentifier returns a new IdentifierNode with the given identifier name.
func NewIdentifier(ident string) *IdentifierNode {
return &IdentifierNode{NodeType: NodeIdentifier, Ident: ident}
}
// SetPos sets the position. NewIdentifier is a public method so we can't modify its signature.
// Chained for convenience.
// TODO: fix one day?
func (i *IdentifierNode) SetPos(pos Pos) *IdentifierNode {
i.Pos = pos
return i
}
// SetTree sets the parent tree for the node. NewIdentifier is a public method so we can't modify its signature.
// Chained for convenience.
// TODO: fix one day?
func (i *IdentifierNode) SetTree(t *Tree) *IdentifierNode {
i.tr = t
return i
}
func (i *IdentifierNode) String() string {
return i.Ident
}
func (i *IdentifierNode) tree() *Tree {
return i.tr
}
func (i *IdentifierNode) Copy() Node {
return NewIdentifier(i.Ident).SetTree(i.tr).SetPos(i.Pos)
}
// VariableNode holds a list of variable names, possibly with chained field
// accesses. The dollar sign is part of the (first) name.
type VariableNode struct {
NodeType
Pos
tr *Tree
Ident []string // Variable name and fields in lexical order.
}
func (t *Tree) newVariable(pos Pos, ident string) *VariableNode {
return &VariableNode{tr: t, NodeType: NodeVariable, Pos: pos, Ident: strings.Split(ident, ".")}
}
func (v *VariableNode) String() string {
s := ""
for i, id := range v.Ident {
if i > 0 {
s += "."
}
s += id
}
return s
}
func (v *VariableNode) tree() *Tree {
return v.tr
}
func (v *VariableNode) Copy() Node {
return &VariableNode{tr: v.tr, NodeType: NodeVariable, Pos: v.Pos, Ident: append([]string{}, v.Ident...)}
}
// DotNode holds the special identifier '.'.
type DotNode struct {
NodeType
Pos
tr *Tree
}
func (t *Tree) newDot(pos Pos) *DotNode {
return &DotNode{tr: t, NodeType: NodeDot, Pos: pos}
}
func (d *DotNode) Type() NodeType {
// Override method on embedded NodeType for API compatibility.
// TODO: Not really a problem; could change API without effect but
// api tool complains.
return NodeDot
}
func (d *DotNode) String() string {
return "."
}
func (d *DotNode) tree() *Tree {
return d.tr
}
func (d *DotNode) Copy() Node {
return d.tr.newDot(d.Pos)
}
// NilNode holds the special identifier 'nil' representing an untyped nil constant.
type NilNode struct {
NodeType
Pos
tr *Tree
}
func (t *Tree) newNil(pos Pos) *NilNode {
return &NilNode{tr: t, NodeType: NodeNil, Pos: pos}
}
func (n *NilNode) Type() NodeType {
// Override method on embedded NodeType for API compatibility.
// TODO: Not really a problem; could change API without effect but
// api tool complains.
return NodeNil
}
func (n *NilNode) String() string {
return "nil"
}
func (n *NilNode) tree() *Tree {
return n.tr
}
func (n *NilNode) Copy() Node {
return n.tr.newNil(n.Pos)
}
// FieldNode holds a field (identifier starting with '.').
// The names may be chained ('.x.y').
// The period is dropped from each ident.
type FieldNode struct {
NodeType
Pos
tr *Tree
Ident []string // The identifiers in lexical order.
}
func (t *Tree) newField(pos Pos, ident string) *FieldNode {
return &FieldNode{tr: t, NodeType: NodeField, Pos: pos, Ident: strings.Split(ident[1:], ".")} // [1:] to drop leading period
}
func (f *FieldNode) String() string {
s := ""
for _, id := range f.Ident {
s += "." + id
}
return s
}
func (f *FieldNode) tree() *Tree {
return f.tr
}
func (f *FieldNode) Copy() Node {
return &FieldNode{tr: f.tr, NodeType: NodeField, Pos: f.Pos, Ident: append([]string{}, f.Ident...)}
}
// ChainNode holds a term followed by a chain of field accesses (identifier starting with '.').
// The names may be chained ('.x.y').
// The periods are dropped from each ident.
type ChainNode struct {
NodeType
Pos
tr *Tree
Node Node
Field []string // The identifiers in lexical order.
}
func (t *Tree) newChain(pos Pos, node Node) *ChainNode {
return &ChainNode{tr: t, NodeType: NodeChain, Pos: pos, Node: node}
}
// Add adds the named field (which should start with a period) to the end of the chain.
func (c *ChainNode) Add(field string) {
if len(field) == 0 || field[0] != '.' {
panic("no dot in field")
}
field = field[1:] // Remove leading dot.
if field == "" {
panic("empty field")
}
c.Field = append(c.Field, field)
}
func (c *ChainNode) String() string {
s := c.Node.String()
if _, ok := c.Node.(*PipeNode); ok {
s = "(" + s + ")"
}
for _, field := range c.Field {
s += "." + field
}
return s
}
func (c *ChainNode) tree() *Tree {
return c.tr
}
func (c *ChainNode) Copy() Node {
return &ChainNode{tr: c.tr, NodeType: NodeChain, Pos: c.Pos, Node: c.Node, Field: append([]string{}, c.Field...)}
}
// BoolNode holds a boolean constant.
type BoolNode struct {
NodeType
Pos
tr *Tree
True bool // The value of the boolean constant.
}
func (t *Tree) newBool(pos Pos, true bool) *BoolNode {
return &BoolNode{tr: t, NodeType: NodeBool, Pos: pos, True: true}
}
func (b *BoolNode) String() string {
if b.True {
return "true"
}
return "false"
}
func (b *BoolNode) tree() *Tree {
return b.tr
}
func (b *BoolNode) Copy() Node {
return b.tr.newBool(b.Pos, b.True)
}
// NumberNode holds a number: signed or unsigned integer, float, or complex.
// The value is parsed and stored under all the types that can represent the value.
// This simulates in a small amount of code the behavior of Go's ideal constants.
type NumberNode struct {
NodeType
Pos
tr *Tree
IsInt bool // Number has an integral value.
IsUint bool // Number has an unsigned integral value.
IsFloat bool // Number has a floating-point value.
IsComplex bool // Number is complex.
Int64 int64 // The signed integer value.
Uint64 uint64 // The unsigned integer value.
Float64 float64 // The floating-point value.
Complex128 complex128 // The complex value.
Text string // The original textual representation from the input.
}
func (t *Tree) newNumber(pos Pos, text string, typ itemType) (*NumberNode, error) {
n := &NumberNode{tr: t, NodeType: NodeNumber, Pos: pos, Text: text}
switch typ {
case itemCharConstant:
rune, _, tail, err := strconv.UnquoteChar(text[1:], text[0])
if err != nil {
return nil, err
}
if tail != "'" {
return nil, fmt.Errorf("malformed character constant: %s", text)
}
n.Int64 = int64(rune)
n.IsInt = true
n.Uint64 = uint64(rune)
n.IsUint = true
n.Float64 = float64(rune) // odd but those are the rules.
n.IsFloat = true
return n, nil
case itemComplex:
// fmt.Sscan can parse the pair, so let it do the work.
if _, err := fmt.Sscan(text, &n.Complex128); err != nil {
return nil, err
}
n.IsComplex = true
n.simplifyComplex()
return n, nil
}
// Imaginary constants can only be complex unless they are zero.
if len(text) > 0 && text[len(text)-1] == 'i' {
f, err := strconv.ParseFloat(text[:len(text)-1], 64)
if err == nil {
n.IsComplex = true
n.Complex128 = complex(0, f)
n.simplifyComplex()
return n, nil
}
}
// Do integer test first so we get 0x123 etc.
u, err := strconv.ParseUint(text, 0, 64) // will fail for -0; fixed below.
if err == nil {
n.IsUint = true
n.Uint64 = u
}
i, err := strconv.ParseInt(text, 0, 64)
if err == nil {
n.IsInt = true
n.Int64 = i
if i == 0 {
n.IsUint = true // in case of -0.
n.Uint64 = u
}
}
// If an integer extraction succeeded, promote the float.
if n.IsInt {
n.IsFloat = true
n.Float64 = float64(n.Int64)
} else if n.IsUint {
n.IsFloat = true
n.Float64 = float64(n.Uint64)
} else {
f, err := strconv.ParseFloat(text, 64)
if err == nil {
n.IsFloat = true
n.Float64 = f
// If a floating-point extraction succeeded, extract the int if needed.
if !n.IsInt && float64(int64(f)) == f {
n.IsInt = true
n.Int64 = int64(f)
}
if !n.IsUint && float64(uint64(f)) == f {
n.IsUint = true
n.Uint64 = uint64(f)
}
}
}
if !n.IsInt && !n.IsUint && !n.IsFloat {
return nil, fmt.Errorf("illegal number syntax: %q", text)
}
return n, nil
}
// simplifyComplex pulls out any other types that are represented by the complex number.
// These all require that the imaginary part be zero.
func (n *NumberNode) simplifyComplex() {
n.IsFloat = imag(n.Complex128) == 0
if n.IsFloat {
n.Float64 = real(n.Complex128)
n.IsInt = float64(int64(n.Float64)) == n.Float64
if n.IsInt {
n.Int64 = int64(n.Float64)
}
n.IsUint = float64(uint64(n.Float64)) == n.Float64
if n.IsUint {
n.Uint64 = uint64(n.Float64)
}
}
}
func (n *NumberNode) String() string {
return n.Text
}
func (n *NumberNode) tree() *Tree {
return n.tr
}
func (n *NumberNode) Copy() Node {
nn := new(NumberNode)
*nn = *n // Easy, fast, correct.
return nn
}
// StringNode holds a string constant. The value has been "unquoted".
type StringNode struct {
NodeType
Pos
tr *Tree
Quoted string // The original text of the string, with quotes.
Text string // The string, after quote processing.
}
func (t *Tree) newString(pos Pos, orig, text string) *StringNode {
return &StringNode{tr: t, NodeType: NodeString, Pos: pos, Quoted: orig, Text: text}
}
func (s *StringNode) String() string {
return s.Quoted
}
func (s *StringNode) tree() *Tree {
return s.tr
}
func (s *StringNode) Copy() Node {
return s.tr.newString(s.Pos, s.Quoted, s.Text)
}
// endNode represents an {{end}} action.
// It does not appear in the final parse tree.
type endNode struct {
NodeType
Pos
tr *Tree
}
func (t *Tree) newEnd(pos Pos) *endNode {
return &endNode{tr: t, NodeType: nodeEnd, Pos: pos}
}
func (e *endNode) String() string {
return "{{end}}"
}
func (e *endNode) tree() *Tree {
return e.tr
}
func (e *endNode) Copy() Node {
return e.tr.newEnd(e.Pos)
}
// elseNode represents an {{else}} action. Does not appear in the final tree.
type elseNode struct {
NodeType
Pos
tr *Tree
Line int // The line number in the input (deprecated; kept for compatibility)
}
func (t *Tree) newElse(pos Pos, line int) *elseNode {
return &elseNode{tr: t, NodeType: nodeElse, Pos: pos, Line: line}
}
func (e *elseNode) Type() NodeType {
return nodeElse
}
func (e *elseNode) String() string {
return "{{else}}"
}
func (e *elseNode) tree() *Tree {
return e.tr
}
func (e *elseNode) Copy() Node {
return e.tr.newElse(e.Pos, e.Line)
}
// BranchNode is the common representation of if, range, and with.
type BranchNode struct {
NodeType
Pos
tr *Tree
Line int // The line number in the input (deprecated; kept for compatibility)
Pipe *PipeNode // The pipeline to be evaluated.
List *ListNode // What to execute if the value is non-empty.
ElseList *ListNode // What to execute if the value is empty (nil if absent).
}
func (b *BranchNode) String() string {
name := ""
switch b.NodeType {
case NodeIf:
name = "if"
case NodeRange:
name = "range"
case NodeWith:
name = "with"
default:
panic("unknown branch type")
}
if b.ElseList != nil {
return fmt.Sprintf("{{%s %s}}%s{{else}}%s{{end}}", name, b.Pipe, b.List, b.ElseList)
}
return fmt.Sprintf("{{%s %s}}%s{{end}}", name, b.Pipe, b.List)
}
func (b *BranchNode) tree() *Tree {
return b.tr
}
func (b *BranchNode) Copy() Node {
switch b.NodeType {
case NodeIf:
return b.tr.newIf(b.Pos, b.Line, b.Pipe, b.List, b.ElseList)
case NodeRange:
return b.tr.newRange(b.Pos, b.Line, b.Pipe, b.List, b.ElseList)
case NodeWith:
return b.tr.newWith(b.Pos, b.Line, b.Pipe, b.List, b.ElseList)
default:
panic("unknown branch type")
}
}
// IfNode represents an {{if}} action and its commands.
type IfNode struct {
BranchNode
}
func (t *Tree) newIf(pos Pos, line int, pipe *PipeNode, list, elseList *ListNode) *IfNode {
return &IfNode{BranchNode{tr: t, NodeType: NodeIf, Pos: pos, Line: line, Pipe: pipe, List: list, ElseList: elseList}}
}
func (i *IfNode) Copy() Node {
return i.tr.newIf(i.Pos, i.Line, i.Pipe.CopyPipe(), i.List.CopyList(), i.ElseList.CopyList())
}
// RangeNode represents a {{range}} action and its commands.
type RangeNode struct {
BranchNode
}
func (t *Tree) newRange(pos Pos, line int, pipe *PipeNode, list, elseList *ListNode) *RangeNode {
return &RangeNode{BranchNode{tr: t, NodeType: NodeRange, Pos: pos, Line: line, Pipe: pipe, List: list, ElseList: elseList}}
}
func (r *RangeNode) Copy() Node {
return r.tr.newRange(r.Pos, r.Line, r.Pipe.CopyPipe(), r.List.CopyList(), r.ElseList.CopyList())
}
// WithNode represents a {{with}} action and its commands.
type WithNode struct {
BranchNode
}
func (t *Tree) newWith(pos Pos, line int, pipe *PipeNode, list, elseList *ListNode) *WithNode {
return &WithNode{BranchNode{tr: t, NodeType: NodeWith, Pos: pos, Line: line, Pipe: pipe, List: list, ElseList: elseList}}
}
func (w *WithNode) Copy() Node {
return w.tr.newWith(w.Pos, w.Line, w.Pipe.CopyPipe(), w.List.CopyList(), w.ElseList.CopyList())
}
// TemplateNode represents a {{template}} action.
type TemplateNode struct {
NodeType
Pos
tr *Tree
Line int // The line number in the input (deprecated; kept for compatibility)
Name string // The name of the template (unquoted).
Pipe *PipeNode // The command to evaluate as dot for the template.
}
func (t *Tree) newTemplate(pos Pos, line int, name string, pipe *PipeNode) *TemplateNode {
return &TemplateNode{tr: t, NodeType: NodeTemplate, Pos: pos, Line: line, Name: name, Pipe: pipe}
}
func (t *TemplateNode) String() string {
if t.Pipe == nil {
return fmt.Sprintf("{{template %q}}", t.Name)
}
return fmt.Sprintf("{{template %q %s}}", t.Name, t.Pipe)
}
func (t *TemplateNode) tree() *Tree {
return t.tr
}
func (t *TemplateNode) Copy() Node {
return t.tr.newTemplate(t.Pos, t.Line, t.Name, t.Pipe.CopyPipe())
}

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@ -0,0 +1,700 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package parse builds parse trees for templates as defined by text/template
// and html/template. Clients should use those packages to construct templates
// rather than this one, which provides shared internal data structures not
// intended for general use.
package parse
import (
"bytes"
"fmt"
"runtime"
"strconv"
"strings"
)
// Tree is the representation of a single parsed template.
type Tree struct {
Name string // name of the template represented by the tree.
ParseName string // name of the top-level template during parsing, for error messages.
Root *ListNode // top-level root of the tree.
text string // text parsed to create the template (or its parent)
// Parsing only; cleared after parse.
funcs []map[string]interface{}
lex *lexer
token [3]item // three-token lookahead for parser.
peekCount int
vars []string // variables defined at the moment.
}
// Copy returns a copy of the Tree. Any parsing state is discarded.
func (t *Tree) Copy() *Tree {
if t == nil {
return nil
}
return &Tree{
Name: t.Name,
ParseName: t.ParseName,
Root: t.Root.CopyList(),
text: t.text,
}
}
// Parse returns a map from template name to parse.Tree, created by parsing the
// templates described in the argument string. The top-level template will be
// given the specified name. If an error is encountered, parsing stops and an
// empty map is returned with the error.
func Parse(name, text, leftDelim, rightDelim string, funcs ...map[string]interface{}) (treeSet map[string]*Tree, err error) {
treeSet = make(map[string]*Tree)
t := New(name)
t.text = text
_, err = t.Parse(text, leftDelim, rightDelim, treeSet, funcs...)
return
}
// next returns the next token.
func (t *Tree) next() item {
if t.peekCount > 0 {
t.peekCount--
} else {
t.token[0] = t.lex.nextItem()
}
return t.token[t.peekCount]
}
// backup backs the input stream up one token.
func (t *Tree) backup() {
t.peekCount++
}
// backup2 backs the input stream up two tokens.
// The zeroth token is already there.
func (t *Tree) backup2(t1 item) {
t.token[1] = t1
t.peekCount = 2
}
// backup3 backs the input stream up three tokens
// The zeroth token is already there.
func (t *Tree) backup3(t2, t1 item) { // Reverse order: we're pushing back.
t.token[1] = t1
t.token[2] = t2
t.peekCount = 3
}
// peek returns but does not consume the next token.
func (t *Tree) peek() item {
if t.peekCount > 0 {
return t.token[t.peekCount-1]
}
t.peekCount = 1
t.token[0] = t.lex.nextItem()
return t.token[0]
}
// nextNonSpace returns the next non-space token.
func (t *Tree) nextNonSpace() (token item) {
for {
token = t.next()
if token.typ != itemSpace {
break
}
}
return token
}
// peekNonSpace returns but does not consume the next non-space token.
func (t *Tree) peekNonSpace() (token item) {
for {
token = t.next()
if token.typ != itemSpace {
break
}
}
t.backup()
return token
}
// Parsing.
// New allocates a new parse tree with the given name.
func New(name string, funcs ...map[string]interface{}) *Tree {
return &Tree{
Name: name,
funcs: funcs,
}
}
// ErrorContext returns a textual representation of the location of the node in the input text.
// The receiver is only used when the node does not have a pointer to the tree inside,
// which can occur in old code.
func (t *Tree) ErrorContext(n Node) (location, context string) {
pos := int(n.Position())
tree := n.tree()
if tree == nil {
tree = t
}
text := tree.text[:pos]
byteNum := strings.LastIndex(text, "\n")
if byteNum == -1 {
byteNum = pos // On first line.
} else {
byteNum++ // After the newline.
byteNum = pos - byteNum
}
lineNum := 1 + strings.Count(text, "\n")
context = n.String()
if len(context) > 20 {
context = fmt.Sprintf("%.20s...", context)
}
return fmt.Sprintf("%s:%d:%d", tree.ParseName, lineNum, byteNum), context
}
// errorf formats the error and terminates processing.
func (t *Tree) errorf(format string, args ...interface{}) {
t.Root = nil
format = fmt.Sprintf("template: %s:%d: %s", t.ParseName, t.lex.lineNumber(), format)
panic(fmt.Errorf(format, args...))
}
// error terminates processing.
func (t *Tree) error(err error) {
t.errorf("%s", err)
}
// expect consumes the next token and guarantees it has the required type.
func (t *Tree) expect(expected itemType, context string) item {
token := t.nextNonSpace()
if token.typ != expected {
t.unexpected(token, context)
}
return token
}
// expectOneOf consumes the next token and guarantees it has one of the required types.
func (t *Tree) expectOneOf(expected1, expected2 itemType, context string) item {
token := t.nextNonSpace()
if token.typ != expected1 && token.typ != expected2 {
t.unexpected(token, context)
}
return token
}
// unexpected complains about the token and terminates processing.
func (t *Tree) unexpected(token item, context string) {
t.errorf("unexpected %s in %s", token, context)
}
// recover is the handler that turns panics into returns from the top level of Parse.
func (t *Tree) recover(errp *error) {
e := recover()
if e != nil {
if _, ok := e.(runtime.Error); ok {
panic(e)
}
if t != nil {
t.stopParse()
}
*errp = e.(error)
}
return
}
// startParse initializes the parser, using the lexer.
func (t *Tree) startParse(funcs []map[string]interface{}, lex *lexer) {
t.Root = nil
t.lex = lex
t.vars = []string{"$"}
t.funcs = funcs
}
// stopParse terminates parsing.
func (t *Tree) stopParse() {
t.lex = nil
t.vars = nil
t.funcs = nil
}
// Parse parses the template definition string to construct a representation of
// the template for execution. If either action delimiter string is empty, the
// default ("{{" or "}}") is used. Embedded template definitions are added to
// the treeSet map.
func (t *Tree) Parse(text, leftDelim, rightDelim string, treeSet map[string]*Tree, funcs ...map[string]interface{}) (tree *Tree, err error) {
defer t.recover(&err)
t.ParseName = t.Name
t.startParse(funcs, lex(t.Name, text, leftDelim, rightDelim))
t.text = text
t.parse(treeSet)
t.add(treeSet)
t.stopParse()
return t, nil
}
// add adds tree to the treeSet.
func (t *Tree) add(treeSet map[string]*Tree) {
tree := treeSet[t.Name]
if tree == nil || IsEmptyTree(tree.Root) {
treeSet[t.Name] = t
return
}
if !IsEmptyTree(t.Root) {
t.errorf("template: multiple definition of template %q", t.Name)
}
}
// IsEmptyTree reports whether this tree (node) is empty of everything but space.
func IsEmptyTree(n Node) bool {
switch n := n.(type) {
case nil:
return true
case *ActionNode:
case *IfNode:
case *ListNode:
for _, node := range n.Nodes {
if !IsEmptyTree(node) {
return false
}
}
return true
case *RangeNode:
case *TemplateNode:
case *TextNode:
return len(bytes.TrimSpace(n.Text)) == 0
case *WithNode:
default:
panic("unknown node: " + n.String())
}
return false
}
// parse is the top-level parser for a template, essentially the same
// as itemList except it also parses {{define}} actions.
// It runs to EOF.
func (t *Tree) parse(treeSet map[string]*Tree) (next Node) {
t.Root = t.newList(t.peek().pos)
for t.peek().typ != itemEOF {
if t.peek().typ == itemLeftDelim {
delim := t.next()
if t.nextNonSpace().typ == itemDefine {
newT := New("definition") // name will be updated once we know it.
newT.text = t.text
newT.ParseName = t.ParseName
newT.startParse(t.funcs, t.lex)
newT.parseDefinition(treeSet)
continue
}
t.backup2(delim)
}
n := t.textOrAction()
if n.Type() == nodeEnd {
t.errorf("unexpected %s", n)
}
t.Root.append(n)
}
return nil
}
// parseDefinition parses a {{define}} ... {{end}} template definition and
// installs the definition in the treeSet map. The "define" keyword has already
// been scanned.
func (t *Tree) parseDefinition(treeSet map[string]*Tree) {
const context = "define clause"
name := t.expectOneOf(itemString, itemRawString, context)
var err error
t.Name, err = strconv.Unquote(name.val)
if err != nil {
t.error(err)
}
t.expect(itemRightDelim, context)
var end Node
t.Root, end = t.itemList()
if end.Type() != nodeEnd {
t.errorf("unexpected %s in %s", end, context)
}
t.add(treeSet)
t.stopParse()
}
// itemList:
// textOrAction*
// Terminates at {{end}} or {{else}}, returned separately.
func (t *Tree) itemList() (list *ListNode, next Node) {
list = t.newList(t.peekNonSpace().pos)
for t.peekNonSpace().typ != itemEOF {
n := t.textOrAction()
switch n.Type() {
case nodeEnd, nodeElse:
return list, n
}
list.append(n)
}
t.errorf("unexpected EOF")
return
}
// textOrAction:
// text | action
func (t *Tree) textOrAction() Node {
switch token := t.nextNonSpace(); token.typ {
case itemElideNewline:
return t.elideNewline()
case itemText:
return t.newText(token.pos, token.val)
case itemLeftDelim:
return t.action()
default:
t.unexpected(token, "input")
}
return nil
}
// elideNewline:
// Remove newlines trailing rightDelim if \\ is present.
func (t *Tree) elideNewline() Node {
token := t.peek()
if token.typ != itemText {
t.unexpected(token, "input")
return nil
}
t.next()
stripped := strings.TrimLeft(token.val, "\n\r")
diff := len(token.val) - len(stripped)
if diff > 0 {
// This is a bit nasty. We mutate the token in-place to remove
// preceding newlines.
token.pos += Pos(diff)
token.val = stripped
}
return t.newText(token.pos, token.val)
}
// Action:
// control
// command ("|" command)*
// Left delim is past. Now get actions.
// First word could be a keyword such as range.
func (t *Tree) action() (n Node) {
switch token := t.nextNonSpace(); token.typ {
case itemElse:
return t.elseControl()
case itemEnd:
return t.endControl()
case itemIf:
return t.ifControl()
case itemRange:
return t.rangeControl()
case itemTemplate:
return t.templateControl()
case itemWith:
return t.withControl()
}
t.backup()
// Do not pop variables; they persist until "end".
return t.newAction(t.peek().pos, t.lex.lineNumber(), t.pipeline("command"))
}
// Pipeline:
// declarations? command ('|' command)*
func (t *Tree) pipeline(context string) (pipe *PipeNode) {
var decl []*VariableNode
pos := t.peekNonSpace().pos
// Are there declarations?
for {
if v := t.peekNonSpace(); v.typ == itemVariable {
t.next()
// Since space is a token, we need 3-token look-ahead here in the worst case:
// in "$x foo" we need to read "foo" (as opposed to ":=") to know that $x is an
// argument variable rather than a declaration. So remember the token
// adjacent to the variable so we can push it back if necessary.
tokenAfterVariable := t.peek()
if next := t.peekNonSpace(); next.typ == itemColonEquals || (next.typ == itemChar && next.val == ",") {
t.nextNonSpace()
variable := t.newVariable(v.pos, v.val)
decl = append(decl, variable)
t.vars = append(t.vars, v.val)
if next.typ == itemChar && next.val == "," {
if context == "range" && len(decl) < 2 {
continue
}
t.errorf("too many declarations in %s", context)
}
} else if tokenAfterVariable.typ == itemSpace {
t.backup3(v, tokenAfterVariable)
} else {
t.backup2(v)
}
}
break
}
pipe = t.newPipeline(pos, t.lex.lineNumber(), decl)
for {
switch token := t.nextNonSpace(); token.typ {
case itemRightDelim, itemRightParen:
if len(pipe.Cmds) == 0 {
t.errorf("missing value for %s", context)
}
if token.typ == itemRightParen {
t.backup()
}
return
case itemBool, itemCharConstant, itemComplex, itemDot, itemField, itemIdentifier,
itemNumber, itemNil, itemRawString, itemString, itemVariable, itemLeftParen:
t.backup()
pipe.append(t.command())
default:
t.unexpected(token, context)
}
}
}
func (t *Tree) parseControl(allowElseIf bool, context string) (pos Pos, line int, pipe *PipeNode, list, elseList *ListNode) {
defer t.popVars(len(t.vars))
line = t.lex.lineNumber()
pipe = t.pipeline(context)
var next Node
list, next = t.itemList()
switch next.Type() {
case nodeEnd: //done
case nodeElse:
if allowElseIf {
// Special case for "else if". If the "else" is followed immediately by an "if",
// the elseControl will have left the "if" token pending. Treat
// {{if a}}_{{else if b}}_{{end}}
// as
// {{if a}}_{{else}}{{if b}}_{{end}}{{end}}.
// To do this, parse the if as usual and stop at it {{end}}; the subsequent{{end}}
// is assumed. This technique works even for long if-else-if chains.
// TODO: Should we allow else-if in with and range?
if t.peek().typ == itemIf {
t.next() // Consume the "if" token.
elseList = t.newList(next.Position())
elseList.append(t.ifControl())
// Do not consume the next item - only one {{end}} required.
break
}
}
elseList, next = t.itemList()
if next.Type() != nodeEnd {
t.errorf("expected end; found %s", next)
}
}
return pipe.Position(), line, pipe, list, elseList
}
// If:
// {{if pipeline}} itemList {{end}}
// {{if pipeline}} itemList {{else}} itemList {{end}}
// If keyword is past.
func (t *Tree) ifControl() Node {
return t.newIf(t.parseControl(true, "if"))
}
// Range:
// {{range pipeline}} itemList {{end}}
// {{range pipeline}} itemList {{else}} itemList {{end}}
// Range keyword is past.
func (t *Tree) rangeControl() Node {
return t.newRange(t.parseControl(false, "range"))
}
// With:
// {{with pipeline}} itemList {{end}}
// {{with pipeline}} itemList {{else}} itemList {{end}}
// If keyword is past.
func (t *Tree) withControl() Node {
return t.newWith(t.parseControl(false, "with"))
}
// End:
// {{end}}
// End keyword is past.
func (t *Tree) endControl() Node {
return t.newEnd(t.expect(itemRightDelim, "end").pos)
}
// Else:
// {{else}}
// Else keyword is past.
func (t *Tree) elseControl() Node {
// Special case for "else if".
peek := t.peekNonSpace()
if peek.typ == itemIf {
// We see "{{else if ... " but in effect rewrite it to {{else}}{{if ... ".
return t.newElse(peek.pos, t.lex.lineNumber())
}
return t.newElse(t.expect(itemRightDelim, "else").pos, t.lex.lineNumber())
}
// Template:
// {{template stringValue pipeline}}
// Template keyword is past. The name must be something that can evaluate
// to a string.
func (t *Tree) templateControl() Node {
var name string
token := t.nextNonSpace()
switch token.typ {
case itemString, itemRawString:
s, err := strconv.Unquote(token.val)
if err != nil {
t.error(err)
}
name = s
default:
t.unexpected(token, "template invocation")
}
var pipe *PipeNode
if t.nextNonSpace().typ != itemRightDelim {
t.backup()
// Do not pop variables; they persist until "end".
pipe = t.pipeline("template")
}
return t.newTemplate(token.pos, t.lex.lineNumber(), name, pipe)
}
// command:
// operand (space operand)*
// space-separated arguments up to a pipeline character or right delimiter.
// we consume the pipe character but leave the right delim to terminate the action.
func (t *Tree) command() *CommandNode {
cmd := t.newCommand(t.peekNonSpace().pos)
for {
t.peekNonSpace() // skip leading spaces.
operand := t.operand()
if operand != nil {
cmd.append(operand)
}
switch token := t.next(); token.typ {
case itemSpace:
continue
case itemError:
t.errorf("%s", token.val)
case itemRightDelim, itemRightParen:
t.backup()
case itemPipe:
default:
t.errorf("unexpected %s in operand; missing space?", token)
}
break
}
if len(cmd.Args) == 0 {
t.errorf("empty command")
}
return cmd
}
// operand:
// term .Field*
// An operand is a space-separated component of a command,
// a term possibly followed by field accesses.
// A nil return means the next item is not an operand.
func (t *Tree) operand() Node {
node := t.term()
if node == nil {
return nil
}
if t.peek().typ == itemField {
chain := t.newChain(t.peek().pos, node)
for t.peek().typ == itemField {
chain.Add(t.next().val)
}
// Compatibility with original API: If the term is of type NodeField
// or NodeVariable, just put more fields on the original.
// Otherwise, keep the Chain node.
// TODO: Switch to Chains always when we can.
switch node.Type() {
case NodeField:
node = t.newField(chain.Position(), chain.String())
case NodeVariable:
node = t.newVariable(chain.Position(), chain.String())
default:
node = chain
}
}
return node
}
// term:
// literal (number, string, nil, boolean)
// function (identifier)
// .
// .Field
// $
// '(' pipeline ')'
// A term is a simple "expression".
// A nil return means the next item is not a term.
func (t *Tree) term() Node {
switch token := t.nextNonSpace(); token.typ {
case itemError:
t.errorf("%s", token.val)
case itemIdentifier:
if !t.hasFunction(token.val) {
t.errorf("function %q not defined", token.val)
}
return NewIdentifier(token.val).SetTree(t).SetPos(token.pos)
case itemDot:
return t.newDot(token.pos)
case itemNil:
return t.newNil(token.pos)
case itemVariable:
return t.useVar(token.pos, token.val)
case itemField:
return t.newField(token.pos, token.val)
case itemBool:
return t.newBool(token.pos, token.val == "true")
case itemCharConstant, itemComplex, itemNumber:
number, err := t.newNumber(token.pos, token.val, token.typ)
if err != nil {
t.error(err)
}
return number
case itemLeftParen:
pipe := t.pipeline("parenthesized pipeline")
if token := t.next(); token.typ != itemRightParen {
t.errorf("unclosed right paren: unexpected %s", token)
}
return pipe
case itemString, itemRawString:
s, err := strconv.Unquote(token.val)
if err != nil {
t.error(err)
}
return t.newString(token.pos, token.val, s)
}
t.backup()
return nil
}
// hasFunction reports if a function name exists in the Tree's maps.
func (t *Tree) hasFunction(name string) bool {
for _, funcMap := range t.funcs {
if funcMap == nil {
continue
}
if funcMap[name] != nil {
return true
}
}
return false
}
// popVars trims the variable list to the specified length
func (t *Tree) popVars(n int) {
t.vars = t.vars[:n]
}
// useVar returns a node for a variable reference. It errors if the
// variable is not defined.
func (t *Tree) useVar(pos Pos, name string) Node {
v := t.newVariable(pos, name)
for _, varName := range t.vars {
if varName == v.Ident[0] {
return v
}
}
t.errorf("undefined variable %q", v.Ident[0])
return nil
}

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@ -0,0 +1,426 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package parse
import (
"flag"
"fmt"
"strings"
"testing"
)
var debug = flag.Bool("debug", false, "show the errors produced by the main tests")
type numberTest struct {
text string
isInt bool
isUint bool
isFloat bool
isComplex bool
int64
uint64
float64
complex128
}
var numberTests = []numberTest{
// basics
{"0", true, true, true, false, 0, 0, 0, 0},
{"-0", true, true, true, false, 0, 0, 0, 0}, // check that -0 is a uint.
{"73", true, true, true, false, 73, 73, 73, 0},
{"073", true, true, true, false, 073, 073, 073, 0},
{"0x73", true, true, true, false, 0x73, 0x73, 0x73, 0},
{"-73", true, false, true, false, -73, 0, -73, 0},
{"+73", true, false, true, false, 73, 0, 73, 0},
{"100", true, true, true, false, 100, 100, 100, 0},
{"1e9", true, true, true, false, 1e9, 1e9, 1e9, 0},
{"-1e9", true, false, true, false, -1e9, 0, -1e9, 0},
{"-1.2", false, false, true, false, 0, 0, -1.2, 0},
{"1e19", false, true, true, false, 0, 1e19, 1e19, 0},
{"-1e19", false, false, true, false, 0, 0, -1e19, 0},
{"4i", false, false, false, true, 0, 0, 0, 4i},
{"-1.2+4.2i", false, false, false, true, 0, 0, 0, -1.2 + 4.2i},
{"073i", false, false, false, true, 0, 0, 0, 73i}, // not octal!
// complex with 0 imaginary are float (and maybe integer)
{"0i", true, true, true, true, 0, 0, 0, 0},
{"-1.2+0i", false, false, true, true, 0, 0, -1.2, -1.2},
{"-12+0i", true, false, true, true, -12, 0, -12, -12},
{"13+0i", true, true, true, true, 13, 13, 13, 13},
// funny bases
{"0123", true, true, true, false, 0123, 0123, 0123, 0},
{"-0x0", true, true, true, false, 0, 0, 0, 0},
{"0xdeadbeef", true, true, true, false, 0xdeadbeef, 0xdeadbeef, 0xdeadbeef, 0},
// character constants
{`'a'`, true, true, true, false, 'a', 'a', 'a', 0},
{`'\n'`, true, true, true, false, '\n', '\n', '\n', 0},
{`'\\'`, true, true, true, false, '\\', '\\', '\\', 0},
{`'\''`, true, true, true, false, '\'', '\'', '\'', 0},
{`'\xFF'`, true, true, true, false, 0xFF, 0xFF, 0xFF, 0},
{`'パ'`, true, true, true, false, 0x30d1, 0x30d1, 0x30d1, 0},
{`'\u30d1'`, true, true, true, false, 0x30d1, 0x30d1, 0x30d1, 0},
{`'\U000030d1'`, true, true, true, false, 0x30d1, 0x30d1, 0x30d1, 0},
// some broken syntax
{text: "+-2"},
{text: "0x123."},
{text: "1e."},
{text: "0xi."},
{text: "1+2."},
{text: "'x"},
{text: "'xx'"},
// Issue 8622 - 0xe parsed as floating point. Very embarrassing.
{"0xef", true, true, true, false, 0xef, 0xef, 0xef, 0},
}
func TestNumberParse(t *testing.T) {
for _, test := range numberTests {
// If fmt.Sscan thinks it's complex, it's complex. We can't trust the output
// because imaginary comes out as a number.
var c complex128
typ := itemNumber
var tree *Tree
if test.text[0] == '\'' {
typ = itemCharConstant
} else {
_, err := fmt.Sscan(test.text, &c)
if err == nil {
typ = itemComplex
}
}
n, err := tree.newNumber(0, test.text, typ)
ok := test.isInt || test.isUint || test.isFloat || test.isComplex
if ok && err != nil {
t.Errorf("unexpected error for %q: %s", test.text, err)
continue
}
if !ok && err == nil {
t.Errorf("expected error for %q", test.text)
continue
}
if !ok {
if *debug {
fmt.Printf("%s\n\t%s\n", test.text, err)
}
continue
}
if n.IsComplex != test.isComplex {
t.Errorf("complex incorrect for %q; should be %t", test.text, test.isComplex)
}
if test.isInt {
if !n.IsInt {
t.Errorf("expected integer for %q", test.text)
}
if n.Int64 != test.int64 {
t.Errorf("int64 for %q should be %d Is %d", test.text, test.int64, n.Int64)
}
} else if n.IsInt {
t.Errorf("did not expect integer for %q", test.text)
}
if test.isUint {
if !n.IsUint {
t.Errorf("expected unsigned integer for %q", test.text)
}
if n.Uint64 != test.uint64 {
t.Errorf("uint64 for %q should be %d Is %d", test.text, test.uint64, n.Uint64)
}
} else if n.IsUint {
t.Errorf("did not expect unsigned integer for %q", test.text)
}
if test.isFloat {
if !n.IsFloat {
t.Errorf("expected float for %q", test.text)
}
if n.Float64 != test.float64 {
t.Errorf("float64 for %q should be %g Is %g", test.text, test.float64, n.Float64)
}
} else if n.IsFloat {
t.Errorf("did not expect float for %q", test.text)
}
if test.isComplex {
if !n.IsComplex {
t.Errorf("expected complex for %q", test.text)
}
if n.Complex128 != test.complex128 {
t.Errorf("complex128 for %q should be %g Is %g", test.text, test.complex128, n.Complex128)
}
} else if n.IsComplex {
t.Errorf("did not expect complex for %q", test.text)
}
}
}
type parseTest struct {
name string
input string
ok bool
result string // what the user would see in an error message.
}
const (
noError = true
hasError = false
)
var parseTests = []parseTest{
{"empty", "", noError,
``},
{"comment", "{{/*\n\n\n*/}}", noError,
``},
{"spaces", " \t\n", noError,
`" \t\n"`},
{"text", "some text", noError,
`"some text"`},
{"emptyAction", "{{}}", hasError,
`{{}}`},
{"field", "{{.X}}", noError,
`{{.X}}`},
{"simple command", "{{printf}}", noError,
`{{printf}}`},
{"$ invocation", "{{$}}", noError,
"{{$}}"},
{"variable invocation", "{{with $x := 3}}{{$x 23}}{{end}}", noError,
"{{with $x := 3}}{{$x 23}}{{end}}"},
{"variable with fields", "{{$.I}}", noError,
"{{$.I}}"},
{"multi-word command", "{{printf `%d` 23}}", noError,
"{{printf `%d` 23}}"},
{"pipeline", "{{.X|.Y}}", noError,
`{{.X | .Y}}`},
{"pipeline with decl", "{{$x := .X|.Y}}", noError,
`{{$x := .X | .Y}}`},
{"nested pipeline", "{{.X (.Y .Z) (.A | .B .C) (.E)}}", noError,
`{{.X (.Y .Z) (.A | .B .C) (.E)}}`},
{"field applied to parentheses", "{{(.Y .Z).Field}}", noError,
`{{(.Y .Z).Field}}`},
{"simple if", "{{if .X}}hello{{end}}", noError,
`{{if .X}}"hello"{{end}}`},
{"if with else", "{{if .X}}true{{else}}false{{end}}", noError,
`{{if .X}}"true"{{else}}"false"{{end}}`},
{"if with else if", "{{if .X}}true{{else if .Y}}false{{end}}", noError,
`{{if .X}}"true"{{else}}{{if .Y}}"false"{{end}}{{end}}`},
{"if else chain", "+{{if .X}}X{{else if .Y}}Y{{else if .Z}}Z{{end}}+", noError,
`"+"{{if .X}}"X"{{else}}{{if .Y}}"Y"{{else}}{{if .Z}}"Z"{{end}}{{end}}{{end}}"+"`},
{"simple range", "{{range .X}}hello{{end}}", noError,
`{{range .X}}"hello"{{end}}`},
{"chained field range", "{{range .X.Y.Z}}hello{{end}}", noError,
`{{range .X.Y.Z}}"hello"{{end}}`},
{"nested range", "{{range .X}}hello{{range .Y}}goodbye{{end}}{{end}}", noError,
`{{range .X}}"hello"{{range .Y}}"goodbye"{{end}}{{end}}`},
{"range with else", "{{range .X}}true{{else}}false{{end}}", noError,
`{{range .X}}"true"{{else}}"false"{{end}}`},
{"range over pipeline", "{{range .X|.M}}true{{else}}false{{end}}", noError,
`{{range .X | .M}}"true"{{else}}"false"{{end}}`},
{"range []int", "{{range .SI}}{{.}}{{end}}", noError,
`{{range .SI}}{{.}}{{end}}`},
{"range 1 var", "{{range $x := .SI}}{{.}}{{end}}", noError,
`{{range $x := .SI}}{{.}}{{end}}`},
{"range 2 vars", "{{range $x, $y := .SI}}{{.}}{{end}}", noError,
`{{range $x, $y := .SI}}{{.}}{{end}}`},
{"constants", "{{range .SI 1 -3.2i true false 'a' nil}}{{end}}", noError,
`{{range .SI 1 -3.2i true false 'a' nil}}{{end}}`},
{"template", "{{template `x`}}", noError,
`{{template "x"}}`},
{"template with arg", "{{template `x` .Y}}", noError,
`{{template "x" .Y}}`},
{"with", "{{with .X}}hello{{end}}", noError,
`{{with .X}}"hello"{{end}}`},
{"with with else", "{{with .X}}hello{{else}}goodbye{{end}}", noError,
`{{with .X}}"hello"{{else}}"goodbye"{{end}}`},
{"elide newline", "{{true}}\\\n ", noError,
`{{true}}" "`},
// Errors.
{"unclosed action", "hello{{range", hasError, ""},
{"unmatched end", "{{end}}", hasError, ""},
{"missing end", "hello{{range .x}}", hasError, ""},
{"missing end after else", "hello{{range .x}}{{else}}", hasError, ""},
{"undefined function", "hello{{undefined}}", hasError, ""},
{"undefined variable", "{{$x}}", hasError, ""},
{"variable undefined after end", "{{with $x := 4}}{{end}}{{$x}}", hasError, ""},
{"variable undefined in template", "{{template $v}}", hasError, ""},
{"declare with field", "{{with $x.Y := 4}}{{end}}", hasError, ""},
{"template with field ref", "{{template .X}}", hasError, ""},
{"template with var", "{{template $v}}", hasError, ""},
{"invalid punctuation", "{{printf 3, 4}}", hasError, ""},
{"multidecl outside range", "{{with $v, $u := 3}}{{end}}", hasError, ""},
{"too many decls in range", "{{range $u, $v, $w := 3}}{{end}}", hasError, ""},
{"dot applied to parentheses", "{{printf (printf .).}}", hasError, ""},
{"adjacent args", "{{printf 3`x`}}", hasError, ""},
{"adjacent args with .", "{{printf `x`.}}", hasError, ""},
{"extra end after if", "{{if .X}}a{{else if .Y}}b{{end}}{{end}}", hasError, ""},
{"invalid newline elision", "{{true}}\\{{true}}", hasError, ""},
// Equals (and other chars) do not assignments make (yet).
{"bug0a", "{{$x := 0}}{{$x}}", noError, "{{$x := 0}}{{$x}}"},
{"bug0b", "{{$x = 1}}{{$x}}", hasError, ""},
{"bug0c", "{{$x ! 2}}{{$x}}", hasError, ""},
{"bug0d", "{{$x % 3}}{{$x}}", hasError, ""},
// Check the parse fails for := rather than comma.
{"bug0e", "{{range $x := $y := 3}}{{end}}", hasError, ""},
// Another bug: variable read must ignore following punctuation.
{"bug1a", "{{$x:=.}}{{$x!2}}", hasError, ""}, // ! is just illegal here.
{"bug1b", "{{$x:=.}}{{$x+2}}", hasError, ""}, // $x+2 should not parse as ($x) (+2).
{"bug1c", "{{$x:=.}}{{$x +2}}", noError, "{{$x := .}}{{$x +2}}"}, // It's OK with a space.
}
var builtins = map[string]interface{}{
"printf": fmt.Sprintf,
}
func testParse(doCopy bool, t *testing.T) {
textFormat = "%q"
defer func() { textFormat = "%s" }()
for _, test := range parseTests {
tmpl, err := New(test.name).Parse(test.input, "", "", make(map[string]*Tree), builtins)
switch {
case err == nil && !test.ok:
t.Errorf("%q: expected error; got none", test.name)
continue
case err != nil && test.ok:
t.Errorf("%q: unexpected error: %v", test.name, err)
continue
case err != nil && !test.ok:
// expected error, got one
if *debug {
fmt.Printf("%s: %s\n\t%s\n", test.name, test.input, err)
}
continue
}
var result string
if doCopy {
result = tmpl.Root.Copy().String()
} else {
result = tmpl.Root.String()
}
if result != test.result {
t.Errorf("%s=(%q): got\n\t%v\nexpected\n\t%v", test.name, test.input, result, test.result)
}
}
}
func TestParse(t *testing.T) {
testParse(false, t)
}
// Same as TestParse, but we copy the node first
func TestParseCopy(t *testing.T) {
testParse(true, t)
}
type isEmptyTest struct {
name string
input string
empty bool
}
var isEmptyTests = []isEmptyTest{
{"empty", ``, true},
{"nonempty", `hello`, false},
{"spaces only", " \t\n \t\n", true},
{"definition", `{{define "x"}}something{{end}}`, true},
{"definitions and space", "{{define `x`}}something{{end}}\n\n{{define `y`}}something{{end}}\n\n", true},
{"definitions and text", "{{define `x`}}something{{end}}\nx\n{{define `y`}}something{{end}}\ny\n", false},
{"definition and action", "{{define `x`}}something{{end}}{{if 3}}foo{{end}}", false},
}
func TestIsEmpty(t *testing.T) {
if !IsEmptyTree(nil) {
t.Errorf("nil tree is not empty")
}
for _, test := range isEmptyTests {
tree, err := New("root").Parse(test.input, "", "", make(map[string]*Tree), nil)
if err != nil {
t.Errorf("%q: unexpected error: %v", test.name, err)
continue
}
if empty := IsEmptyTree(tree.Root); empty != test.empty {
t.Errorf("%q: expected %t got %t", test.name, test.empty, empty)
}
}
}
func TestErrorContextWithTreeCopy(t *testing.T) {
tree, err := New("root").Parse("{{if true}}{{end}}", "", "", make(map[string]*Tree), nil)
if err != nil {
t.Fatalf("unexpected tree parse failure: %v", err)
}
treeCopy := tree.Copy()
wantLocation, wantContext := tree.ErrorContext(tree.Root.Nodes[0])
gotLocation, gotContext := treeCopy.ErrorContext(treeCopy.Root.Nodes[0])
if wantLocation != gotLocation {
t.Errorf("wrong error location want %q got %q", wantLocation, gotLocation)
}
if wantContext != gotContext {
t.Errorf("wrong error location want %q got %q", wantContext, gotContext)
}
}
// All failures, and the result is a string that must appear in the error message.
var errorTests = []parseTest{
// Check line numbers are accurate.
{"unclosed1",
"line1\n{{",
hasError, `unclosed1:2: unexpected unclosed action in command`},
{"unclosed2",
"line1\n{{define `x`}}line2\n{{",
hasError, `unclosed2:3: unexpected unclosed action in command`},
// Specific errors.
{"function",
"{{foo}}",
hasError, `function "foo" not defined`},
{"comment",
"{{/*}}",
hasError, `unclosed comment`},
{"lparen",
"{{.X (1 2 3}}",
hasError, `unclosed left paren`},
{"rparen",
"{{.X 1 2 3)}}",
hasError, `unexpected ")"`},
{"space",
"{{`x`3}}",
hasError, `missing space?`},
{"idchar",
"{{a#}}",
hasError, `'#'`},
{"charconst",
"{{'a}}",
hasError, `unterminated character constant`},
{"stringconst",
`{{"a}}`,
hasError, `unterminated quoted string`},
{"rawstringconst",
"{{`a}}",
hasError, `unterminated raw quoted string`},
{"number",
"{{0xi}}",
hasError, `number syntax`},
{"multidefine",
"{{define `a`}}a{{end}}{{define `a`}}b{{end}}",
hasError, `multiple definition of template`},
{"eof",
"{{range .X}}",
hasError, `unexpected EOF`},
{"variable",
// Declare $x so it's defined, to avoid that error, and then check we don't parse a declaration.
"{{$x := 23}}{{with $x.y := 3}}{{$x 23}}{{end}}",
hasError, `unexpected ":="`},
{"multidecl",
"{{$a,$b,$c := 23}}",
hasError, `too many declarations`},
{"undefvar",
"{{$a}}",
hasError, `undefined variable`},
}
func TestErrors(t *testing.T) {
for _, test := range errorTests {
_, err := New(test.name).Parse(test.input, "", "", make(map[string]*Tree))
if err == nil {
t.Errorf("%q: expected error", test.name)
continue
}
if !strings.Contains(err.Error(), test.result) {
t.Errorf("%q: error %q does not contain %q", test.name, err, test.result)
}
}
}

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@ -0,0 +1,217 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package template
import (
"fmt"
"github.com/alecthomas/template/parse"
"reflect"
)
// common holds the information shared by related templates.
type common struct {
tmpl map[string]*Template
// We use two maps, one for parsing and one for execution.
// This separation makes the API cleaner since it doesn't
// expose reflection to the client.
parseFuncs FuncMap
execFuncs map[string]reflect.Value
}
// Template is the representation of a parsed template. The *parse.Tree
// field is exported only for use by html/template and should be treated
// as unexported by all other clients.
type Template struct {
name string
*parse.Tree
*common
leftDelim string
rightDelim string
}
// New allocates a new template with the given name.
func New(name string) *Template {
return &Template{
name: name,
}
}
// Name returns the name of the template.
func (t *Template) Name() string {
return t.name
}
// New allocates a new template associated with the given one and with the same
// delimiters. The association, which is transitive, allows one template to
// invoke another with a {{template}} action.
func (t *Template) New(name string) *Template {
t.init()
return &Template{
name: name,
common: t.common,
leftDelim: t.leftDelim,
rightDelim: t.rightDelim,
}
}
func (t *Template) init() {
if t.common == nil {
t.common = new(common)
t.tmpl = make(map[string]*Template)
t.parseFuncs = make(FuncMap)
t.execFuncs = make(map[string]reflect.Value)
}
}
// Clone returns a duplicate of the template, including all associated
// templates. The actual representation is not copied, but the name space of
// associated templates is, so further calls to Parse in the copy will add
// templates to the copy but not to the original. Clone can be used to prepare
// common templates and use them with variant definitions for other templates
// by adding the variants after the clone is made.
func (t *Template) Clone() (*Template, error) {
nt := t.copy(nil)
nt.init()
nt.tmpl[t.name] = nt
for k, v := range t.tmpl {
if k == t.name { // Already installed.
continue
}
// The associated templates share nt's common structure.
tmpl := v.copy(nt.common)
nt.tmpl[k] = tmpl
}
for k, v := range t.parseFuncs {
nt.parseFuncs[k] = v
}
for k, v := range t.execFuncs {
nt.execFuncs[k] = v
}
return nt, nil
}
// copy returns a shallow copy of t, with common set to the argument.
func (t *Template) copy(c *common) *Template {
nt := New(t.name)
nt.Tree = t.Tree
nt.common = c
nt.leftDelim = t.leftDelim
nt.rightDelim = t.rightDelim
return nt
}
// AddParseTree creates a new template with the name and parse tree
// and associates it with t.
func (t *Template) AddParseTree(name string, tree *parse.Tree) (*Template, error) {
if t.common != nil && t.tmpl[name] != nil {
return nil, fmt.Errorf("template: redefinition of template %q", name)
}
nt := t.New(name)
nt.Tree = tree
t.tmpl[name] = nt
return nt, nil
}
// Templates returns a slice of the templates associated with t, including t
// itself.
func (t *Template) Templates() []*Template {
if t.common == nil {
return nil
}
// Return a slice so we don't expose the map.
m := make([]*Template, 0, len(t.tmpl))
for _, v := range t.tmpl {
m = append(m, v)
}
return m
}
// Delims sets the action delimiters to the specified strings, to be used in
// subsequent calls to Parse, ParseFiles, or ParseGlob. Nested template
// definitions will inherit the settings. An empty delimiter stands for the
// corresponding default: {{ or }}.
// The return value is the template, so calls can be chained.
func (t *Template) Delims(left, right string) *Template {
t.leftDelim = left
t.rightDelim = right
return t
}
// Funcs adds the elements of the argument map to the template's function map.
// It panics if a value in the map is not a function with appropriate return
// type. However, it is legal to overwrite elements of the map. The return
// value is the template, so calls can be chained.
func (t *Template) Funcs(funcMap FuncMap) *Template {
t.init()
addValueFuncs(t.execFuncs, funcMap)
addFuncs(t.parseFuncs, funcMap)
return t
}
// Lookup returns the template with the given name that is associated with t,
// or nil if there is no such template.
func (t *Template) Lookup(name string) *Template {
if t.common == nil {
return nil
}
return t.tmpl[name]
}
// Parse parses a string into a template. Nested template definitions will be
// associated with the top-level template t. Parse may be called multiple times
// to parse definitions of templates to associate with t. It is an error if a
// resulting template is non-empty (contains content other than template
// definitions) and would replace a non-empty template with the same name.
// (In multiple calls to Parse with the same receiver template, only one call
// can contain text other than space, comments, and template definitions.)
func (t *Template) Parse(text string) (*Template, error) {
t.init()
trees, err := parse.Parse(t.name, text, t.leftDelim, t.rightDelim, t.parseFuncs, builtins)
if err != nil {
return nil, err
}
// Add the newly parsed trees, including the one for t, into our common structure.
for name, tree := range trees {
// If the name we parsed is the name of this template, overwrite this template.
// The associate method checks it's not a redefinition.
tmpl := t
if name != t.name {
tmpl = t.New(name)
}
// Even if t == tmpl, we need to install it in the common.tmpl map.
if replace, err := t.associate(tmpl, tree); err != nil {
return nil, err
} else if replace {
tmpl.Tree = tree
}
tmpl.leftDelim = t.leftDelim
tmpl.rightDelim = t.rightDelim
}
return t, nil
}
// associate installs the new template into the group of templates associated
// with t. It is an error to reuse a name except to overwrite an empty
// template. The two are already known to share the common structure.
// The boolean return value reports wither to store this tree as t.Tree.
func (t *Template) associate(new *Template, tree *parse.Tree) (bool, error) {
if new.common != t.common {
panic("internal error: associate not common")
}
name := new.name
if old := t.tmpl[name]; old != nil {
oldIsEmpty := parse.IsEmptyTree(old.Root)
newIsEmpty := parse.IsEmptyTree(tree.Root)
if newIsEmpty {
// Whether old is empty or not, new is empty; no reason to replace old.
return false, nil
}
if !oldIsEmpty {
return false, fmt.Errorf("template: redefinition of template %q", name)
}
}
t.tmpl[name] = new
return true, nil
}

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{{define "x"}}TEXT{{end}}
{{define "dotV"}}{{.V}}{{end}}

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@ -0,0 +1,2 @@
{{define "dot"}}{{.}}{{end}}
{{define "nested"}}{{template "dot" .}}{{end}}

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@ -0,0 +1,3 @@
template1
{{define "x"}}x{{end}}
{{template "y"}}

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@ -0,0 +1,3 @@
template2
{{define "y"}}y{{end}}
{{template "x"}}

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@ -0,0 +1,19 @@
Copyright (C) 2014 Alec Thomas
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
of the Software, and to permit persons to whom the Software is furnished to do
so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

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# Units - Helpful unit multipliers and functions for Go
The goal of this package is to have functionality similar to the [time](http://golang.org/pkg/time/) package.
It allows for code like this:
```go
n, err := ParseBase2Bytes("1KB")
// n == 1024
n = units.Mebibyte * 512
```

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package units
// Base2Bytes is the old non-SI power-of-2 byte scale (1024 bytes in a kilobyte,
// etc.).
type Base2Bytes int64
// Base-2 byte units.
const (
Kibibyte Base2Bytes = 1024
KiB = Kibibyte
Mebibyte = Kibibyte * 1024
MiB = Mebibyte
Gibibyte = Mebibyte * 1024
GiB = Gibibyte
Tebibyte = Gibibyte * 1024
TiB = Tebibyte
Pebibyte = Tebibyte * 1024
PiB = Pebibyte
Exbibyte = Pebibyte * 1024
EiB = Exbibyte
)
var (
bytesUnitMap = MakeUnitMap("iB", "B", 1024)
oldBytesUnitMap = MakeUnitMap("B", "B", 1024)
)
// ParseBase2Bytes supports both iB and B in base-2 multipliers. That is, KB
// and KiB are both 1024.
func ParseBase2Bytes(s string) (Base2Bytes, error) {
n, err := ParseUnit(s, bytesUnitMap)
if err != nil {
n, err = ParseUnit(s, oldBytesUnitMap)
}
return Base2Bytes(n), err
}
func (b Base2Bytes) String() string {
return ToString(int64(b), 1024, "iB", "B")
}
var (
metricBytesUnitMap = MakeUnitMap("B", "B", 1000)
)
// MetricBytes are SI byte units (1000 bytes in a kilobyte).
type MetricBytes SI
// SI base-10 byte units.
const (
Kilobyte MetricBytes = 1000
KB = Kilobyte
Megabyte = Kilobyte * 1000
MB = Megabyte
Gigabyte = Megabyte * 1000
GB = Gigabyte
Terabyte = Gigabyte * 1000
TB = Terabyte
Petabyte = Terabyte * 1000
PB = Petabyte
Exabyte = Petabyte * 1000
EB = Exabyte
)
// ParseMetricBytes parses base-10 metric byte units. That is, KB is 1000 bytes.
func ParseMetricBytes(s string) (MetricBytes, error) {
n, err := ParseUnit(s, metricBytesUnitMap)
return MetricBytes(n), err
}
func (m MetricBytes) String() string {
return ToString(int64(m), 1000, "B", "B")
}
// ParseStrictBytes supports both iB and B suffixes for base 2 and metric,
// respectively. That is, KiB represents 1024 and KB represents 1000.
func ParseStrictBytes(s string) (int64, error) {
n, err := ParseUnit(s, bytesUnitMap)
if err != nil {
n, err = ParseUnit(s, metricBytesUnitMap)
}
return int64(n), err
}

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package units
import (
"testing"
"github.com/stretchr/testify/assert"
)
func TestBase2BytesString(t *testing.T) {
assert.Equal(t, Base2Bytes(0).String(), "0B")
assert.Equal(t, Base2Bytes(1025).String(), "1KiB1B")
assert.Equal(t, Base2Bytes(1048577).String(), "1MiB1B")
}
func TestParseBase2Bytes(t *testing.T) {
n, err := ParseBase2Bytes("0B")
assert.NoError(t, err)
assert.Equal(t, 0, n)
n, err = ParseBase2Bytes("1KB")
assert.NoError(t, err)
assert.Equal(t, 1024, n)
n, err = ParseBase2Bytes("1MB1KB25B")
assert.NoError(t, err)
assert.Equal(t, 1049625, n)
n, err = ParseBase2Bytes("1.5MB")
assert.NoError(t, err)
assert.Equal(t, 1572864, n)
}
func TestMetricBytesString(t *testing.T) {
assert.Equal(t, MetricBytes(0).String(), "0B")
assert.Equal(t, MetricBytes(1001).String(), "1KB1B")
assert.Equal(t, MetricBytes(1001025).String(), "1MB1KB25B")
}
func TestParseMetricBytes(t *testing.T) {
n, err := ParseMetricBytes("0B")
assert.NoError(t, err)
assert.Equal(t, 0, n)
n, err = ParseMetricBytes("1KB1B")
assert.NoError(t, err)
assert.Equal(t, 1001, n)
n, err = ParseMetricBytes("1MB1KB25B")
assert.NoError(t, err)
assert.Equal(t, 1001025, n)
n, err = ParseMetricBytes("1.5MB")
assert.NoError(t, err)
assert.Equal(t, 1500000, n)
}

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// Package units provides helpful unit multipliers and functions for Go.
//
// The goal of this package is to have functionality similar to the time [1] package.
//
//
// [1] http://golang.org/pkg/time/
//
// It allows for code like this:
//
// n, err := ParseBase2Bytes("1KB")
// // n == 1024
// n = units.Mebibyte * 512
package units

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package units
// SI units.
type SI int64
// SI unit multiples.
const (
Kilo SI = 1000
Mega = Kilo * 1000
Giga = Mega * 1000
Tera = Giga * 1000
Peta = Tera * 1000
Exa = Peta * 1000
)
func MakeUnitMap(suffix, shortSuffix string, scale int64) map[string]float64 {
return map[string]float64{
shortSuffix: 1,
"K" + suffix: float64(scale),
"M" + suffix: float64(scale * scale),
"G" + suffix: float64(scale * scale * scale),
"T" + suffix: float64(scale * scale * scale * scale),
"P" + suffix: float64(scale * scale * scale * scale * scale),
"E" + suffix: float64(scale * scale * scale * scale * scale * scale),
}
}

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package units
import (
"errors"
"fmt"
"strings"
)
var (
siUnits = []string{"", "K", "M", "G", "T", "P", "E"}
)
func ToString(n int64, scale int64, suffix, baseSuffix string) string {
mn := len(siUnits)
out := make([]string, mn)
for i, m := range siUnits {
if n%scale != 0 || i == 0 && n == 0 {
s := suffix
if i == 0 {
s = baseSuffix
}
out[mn-1-i] = fmt.Sprintf("%d%s%s", n%scale, m, s)
}
n /= scale
if n == 0 {
break
}
}
return strings.Join(out, "")
}
// Below code ripped straight from http://golang.org/src/pkg/time/format.go?s=33392:33438#L1123
var errLeadingInt = errors.New("units: bad [0-9]*") // never printed
// leadingInt consumes the leading [0-9]* from s.
func leadingInt(s string) (x int64, rem string, err error) {
i := 0
for ; i < len(s); i++ {
c := s[i]
if c < '0' || c > '9' {
break
}
if x >= (1<<63-10)/10 {
// overflow
return 0, "", errLeadingInt
}
x = x*10 + int64(c) - '0'
}
return x, s[i:], nil
}
func ParseUnit(s string, unitMap map[string]float64) (int64, error) {
// [-+]?([0-9]*(\.[0-9]*)?[a-z]+)+
orig := s
f := float64(0)
neg := false
// Consume [-+]?
if s != "" {
c := s[0]
if c == '-' || c == '+' {
neg = c == '-'
s = s[1:]
}
}
// Special case: if all that is left is "0", this is zero.
if s == "0" {
return 0, nil
}
if s == "" {
return 0, errors.New("units: invalid " + orig)
}
for s != "" {
g := float64(0) // this element of the sequence
var x int64
var err error
// The next character must be [0-9.]
if !(s[0] == '.' || ('0' <= s[0] && s[0] <= '9')) {
return 0, errors.New("units: invalid " + orig)
}
// Consume [0-9]*
pl := len(s)
x, s, err = leadingInt(s)
if err != nil {
return 0, errors.New("units: invalid " + orig)
}
g = float64(x)
pre := pl != len(s) // whether we consumed anything before a period
// Consume (\.[0-9]*)?
post := false
if s != "" && s[0] == '.' {
s = s[1:]
pl := len(s)
x, s, err = leadingInt(s)
if err != nil {
return 0, errors.New("units: invalid " + orig)
}
scale := 1.0
for n := pl - len(s); n > 0; n-- {
scale *= 10
}
g += float64(x) / scale
post = pl != len(s)
}
if !pre && !post {
// no digits (e.g. ".s" or "-.s")
return 0, errors.New("units: invalid " + orig)
}
// Consume unit.
i := 0
for ; i < len(s); i++ {
c := s[i]
if c == '.' || ('0' <= c && c <= '9') {
break
}
}
u := s[:i]
s = s[i:]
unit, ok := unitMap[u]
if !ok {
return 0, errors.New("units: unknown unit " + u + " in " + orig)
}
f += g * unit
}
if neg {
f = -f
}
if f < float64(-1<<63) || f > float64(1<<63-1) {
return 0, errors.New("units: overflow parsing unit")
}
return int64(f), nil
}

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# Compiled Object files, Static and Dynamic libs (Shared Objects)
*.o
*.a
*.so
# Folders
_obj
_test
# Architecture specific extensions/prefixes
*.[568vq]
[568vq].out
*.cgo1.go
*.cgo2.c
_cgo_defun.c
_cgo_gotypes.go
_cgo_export.*
_testmain.go
*.exe

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language: go
go: 1.3.3

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@ -0,0 +1,20 @@
The MIT License (MIT)
Copyright (c) 2014 Cenk Altı
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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# Exponential Backoff [![GoDoc][godoc image]][godoc] [![Build Status][travis image]][travis]
This is a Go port of the exponential backoff algorithm from [Google's HTTP Client Library for Java][google-http-java-client].
[Exponential backoff][exponential backoff wiki]
is an algorithm that uses feedback to multiplicatively decrease the rate of some process,
in order to gradually find an acceptable rate.
The retries exponentially increase and stop increasing when a certain threshold is met.
## How To
We define two functions, `Retry()` and `RetryNotify()`.
They receive an `Operation` to execute, a `BackOff` algorithm,
and an optional `Notify` error handler.
The operation will be executed, and will be retried on failure with delay
as given by the backoff algorithm. The backoff algorithm can also decide when to stop
retrying.
In addition, the notify error handler will be called after each failed attempt,
except for the last time, whose error should be handled by the caller.
```go
// An Operation is executing by Retry() or RetryNotify().
// The operation will be retried using a backoff policy if it returns an error.
type Operation func() error
// Notify is a notify-on-error function. It receives an operation error and
// backoff delay if the operation failed (with an error).
//
// NOTE that if the backoff policy stated to stop retrying,
// the notify function isn't called.
type Notify func(error, time.Duration)
func Retry(Operation, BackOff) error
func RetryNotify(Operation, BackOff, Notify)
```
## Examples
See more advanced examples in the [godoc][advanced example].
### Retry
Simple retry helper that uses the default exponential backoff algorithm:
```go
operation := func() error {
// An operation that might fail.
return nil // or return errors.New("some error")
}
err := Retry(operation, NewExponentialBackOff())
if err != nil {
// Handle error.
return err
}
// Operation is successful.
return nil
```
### Ticker
```go
operation := func() error {
// An operation that might fail
return nil // or return errors.New("some error")
}
b := NewExponentialBackOff()
ticker := NewTicker(b)
var err error
// Ticks will continue to arrive when the previous operation is still running,
// so operations that take a while to fail could run in quick succession.
for range ticker.C {
if err = operation(); err != nil {
log.Println(err, "will retry...")
continue
}
ticker.Stop()
break
}
if err != nil {
// Operation has failed.
return err
}
// Operation is successful.
return nil
```
## Getting Started
```bash
# install
$ go get github.com/cenkalti/backoff
# test
$ cd $GOPATH/src/github.com/cenkalti/backoff
$ go get -t ./...
$ go test -v -cover
```
[godoc]: https://godoc.org/github.com/cenkalti/backoff
[godoc image]: https://godoc.org/github.com/cenkalti/backoff?status.png
[travis]: https://travis-ci.org/cenkalti/backoff
[travis image]: https://travis-ci.org/cenkalti/backoff.png
[google-http-java-client]: https://github.com/google/google-http-java-client
[exponential backoff wiki]: http://en.wikipedia.org/wiki/Exponential_backoff
[advanced example]: https://godoc.org/github.com/cenkalti/backoff#example_

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package backoff
import (
"io/ioutil"
"log"
"net/http"
"time"
)
// This is an example that demonstrates how this package could be used
// to perform various advanced operations.
//
// It executes an HTTP GET request with exponential backoff,
// while errors are logged and failed responses are closed, as required by net/http package.
//
// Note we define a condition function which is used inside the operation to
// determine whether the operation succeeded or failed.
func Example() error {
res, err := GetWithRetry(
"http://localhost:9999",
ErrorIfStatusCodeIsNot(http.StatusOK),
NewExponentialBackOff())
if err != nil {
// Close response body of last (failed) attempt.
// The Last attempt isn't handled by the notify-on-error function,
// which closes the body of all the previous attempts.
if e := res.Body.Close(); e != nil {
log.Printf("error closing last attempt's response body: %s", e)
}
log.Printf("too many failed request attempts: %s", err)
return err
}
defer res.Body.Close() // The response's Body must be closed.
// Read body
_, _ = ioutil.ReadAll(res.Body)
// Do more stuff
return nil
}
// GetWithRetry is a helper function that performs an HTTP GET request
// to the given URL, and retries with the given backoff using the given condition function.
//
// It also uses a notify-on-error function which logs
// and closes the response body of the failed request.
func GetWithRetry(url string, condition Condition, bck BackOff) (*http.Response, error) {
var res *http.Response
err := RetryNotify(
func() error {
var err error
res, err = http.Get(url)
if err != nil {
return err
}
return condition(res)
},
bck,
LogAndClose())
return res, err
}
// Condition is a retry condition function.
// It receives a response, and returns an error
// if the response failed the condition.
type Condition func(*http.Response) error
// ErrorIfStatusCodeIsNot returns a retry condition function.
// The condition returns an error
// if the given response's status code is not the given HTTP status code.
func ErrorIfStatusCodeIsNot(status int) Condition {
return func(res *http.Response) error {
if res.StatusCode != status {
return NewError(res)
}
return nil
}
}
// Error is returned on ErrorIfX() condition functions throughout this package.
type Error struct {
Response *http.Response
}
func NewError(res *http.Response) *Error {
// Sanity check
if res == nil {
panic("response object is nil")
}
return &Error{Response: res}
}
func (err *Error) Error() string { return "request failed" }
// LogAndClose is a notify-on-error function.
// It logs the error and closes the response body.
func LogAndClose() Notify {
return func(err error, wait time.Duration) {
switch e := err.(type) {
case *Error:
defer e.Response.Body.Close()
b, err := ioutil.ReadAll(e.Response.Body)
var body string
if err != nil {
body = "can't read body"
} else {
body = string(b)
}
log.Printf("%s: %s", e.Response.Status, body)
default:
log.Println(err)
}
}
}

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// Package backoff implements backoff algorithms for retrying operations.
//
// Also has a Retry() helper for retrying operations that may fail.
package backoff
import "time"
// BackOff is a backoff policy for retrying an operation.
type BackOff interface {
// NextBackOff returns the duration to wait before retrying the operation,
// or backoff.Stop to indicate that no more retries should be made.
//
// Example usage:
//
// duration := backoff.NextBackOff();
// if (duration == backoff.Stop) {
// // Do not retry operation.
// } else {
// // Sleep for duration and retry operation.
// }
//
NextBackOff() time.Duration
// Reset to initial state.
Reset()
}
// Indicates that no more retries should be made for use in NextBackOff().
const Stop time.Duration = -1
// ZeroBackOff is a fixed backoff policy whose backoff time is always zero,
// meaning that the operation is retried immediately without waiting, indefinitely.
type ZeroBackOff struct{}
func (b *ZeroBackOff) Reset() {}
func (b *ZeroBackOff) NextBackOff() time.Duration { return 0 }
// StopBackOff is a fixed backoff policy that always returns backoff.Stop for
// NextBackOff(), meaning that the operation should never be retried.
type StopBackOff struct{}
func (b *StopBackOff) Reset() {}
func (b *StopBackOff) NextBackOff() time.Duration { return Stop }
// ConstantBackOff is a backoff policy that always returns the same backoff delay.
// This is in contrast to an exponential backoff policy,
// which returns a delay that grows longer as you call NextBackOff() over and over again.
type ConstantBackOff struct {
Interval time.Duration
}
func (b *ConstantBackOff) Reset() {}
func (b *ConstantBackOff) NextBackOff() time.Duration { return b.Interval }
func NewConstantBackOff(d time.Duration) *ConstantBackOff {
return &ConstantBackOff{Interval: d}
}

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package backoff
import (
"testing"
"time"
)
func TestNextBackOffMillis(t *testing.T) {
subtestNextBackOff(t, 0, new(ZeroBackOff))
subtestNextBackOff(t, Stop, new(StopBackOff))
}
func subtestNextBackOff(t *testing.T, expectedValue time.Duration, backOffPolicy BackOff) {
for i := 0; i < 10; i++ {
next := backOffPolicy.NextBackOff()
if next != expectedValue {
t.Errorf("got: %d expected: %d", next, expectedValue)
}
}
}
func TestConstantBackOff(t *testing.T) {
backoff := NewConstantBackOff(time.Second)
if backoff.NextBackOff() != time.Second {
t.Error("invalid interval")
}
}

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package backoff
import "log"
func ExampleRetry() error {
operation := func() error {
// An operation that might fail.
return nil // or return errors.New("some error")
}
err := Retry(operation, NewExponentialBackOff())
if err != nil {
// Handle error.
return err
}
// Operation is successful.
return nil
}
func ExampleTicker() error {
operation := func() error {
// An operation that might fail
return nil // or return errors.New("some error")
}
b := NewExponentialBackOff()
ticker := NewTicker(b)
var err error
// Ticks will continue to arrive when the previous operation is still running,
// so operations that take a while to fail could run in quick succession.
for _ = range ticker.C {
if err = operation(); err != nil {
log.Println(err, "will retry...")
continue
}
ticker.Stop()
break
}
if err != nil {
// Operation has failed.
return err
}
// Operation is successful.
return nil
}

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package backoff
import (
"math/rand"
"time"
)
/*
ExponentialBackOff is a backoff implementation that increases the backoff
period for each retry attempt using a randomization function that grows exponentially.
NextBackOff() is calculated using the following formula:
randomized interval =
RetryInterval * (random value in range [1 - RandomizationFactor, 1 + RandomizationFactor])
In other words NextBackOff() will range between the randomization factor
percentage below and above the retry interval.
For example, given the following parameters:
RetryInterval = 2
RandomizationFactor = 0.5
Multiplier = 2
the actual backoff period used in the next retry attempt will range between 1 and 3 seconds,
multiplied by the exponential, that is, between 2 and 6 seconds.
Note: MaxInterval caps the RetryInterval and not the randomized interval.
If the time elapsed since an ExponentialBackOff instance is created goes past the
MaxElapsedTime, then the method NextBackOff() starts returning backoff.Stop.
The elapsed time can be reset by calling Reset().
Example: Given the following default arguments, for 10 tries the sequence will be,
and assuming we go over the MaxElapsedTime on the 10th try:
Request # RetryInterval (seconds) Randomized Interval (seconds)
1 0.5 [0.25, 0.75]
2 0.75 [0.375, 1.125]
3 1.125 [0.562, 1.687]
4 1.687 [0.8435, 2.53]
5 2.53 [1.265, 3.795]
6 3.795 [1.897, 5.692]
7 5.692 [2.846, 8.538]
8 8.538 [4.269, 12.807]
9 12.807 [6.403, 19.210]
10 19.210 backoff.Stop
Note: Implementation is not thread-safe.
*/
type ExponentialBackOff struct {
InitialInterval time.Duration
RandomizationFactor float64
Multiplier float64
MaxInterval time.Duration
// After MaxElapsedTime the ExponentialBackOff stops.
// It never stops if MaxElapsedTime == 0.
MaxElapsedTime time.Duration
Clock Clock
currentInterval time.Duration
startTime time.Time
}
// Clock is an interface that returns current time for BackOff.
type Clock interface {
Now() time.Time
}
// Default values for ExponentialBackOff.
const (
DefaultInitialInterval = 500 * time.Millisecond
DefaultRandomizationFactor = 0.5
DefaultMultiplier = 1.5
DefaultMaxInterval = 60 * time.Second
DefaultMaxElapsedTime = 15 * time.Minute
)
// NewExponentialBackOff creates an instance of ExponentialBackOff using default values.
func NewExponentialBackOff() *ExponentialBackOff {
b := &ExponentialBackOff{
InitialInterval: DefaultInitialInterval,
RandomizationFactor: DefaultRandomizationFactor,
Multiplier: DefaultMultiplier,
MaxInterval: DefaultMaxInterval,
MaxElapsedTime: DefaultMaxElapsedTime,
Clock: SystemClock,
}
b.Reset()
return b
}
type systemClock struct{}
func (t systemClock) Now() time.Time {
return time.Now()
}
// SystemClock implements Clock interface that uses time.Now().
var SystemClock = systemClock{}
// Reset the interval back to the initial retry interval and restarts the timer.
func (b *ExponentialBackOff) Reset() {
b.currentInterval = b.InitialInterval
b.startTime = b.Clock.Now()
}
// NextBackOff calculates the next backoff interval using the formula:
// Randomized interval = RetryInterval +/- (RandomizationFactor * RetryInterval)
func (b *ExponentialBackOff) NextBackOff() time.Duration {
// Make sure we have not gone over the maximum elapsed time.
if b.MaxElapsedTime != 0 && b.GetElapsedTime() > b.MaxElapsedTime {
return Stop
}
defer b.incrementCurrentInterval()
return getRandomValueFromInterval(b.RandomizationFactor, rand.Float64(), b.currentInterval)
}
// GetElapsedTime returns the elapsed time since an ExponentialBackOff instance
// is created and is reset when Reset() is called.
//
// The elapsed time is computed using time.Now().UnixNano().
func (b *ExponentialBackOff) GetElapsedTime() time.Duration {
return b.Clock.Now().Sub(b.startTime)
}
// Increments the current interval by multiplying it with the multiplier.
func (b *ExponentialBackOff) incrementCurrentInterval() {
// Check for overflow, if overflow is detected set the current interval to the max interval.
if float64(b.currentInterval) >= float64(b.MaxInterval)/b.Multiplier {
b.currentInterval = b.MaxInterval
} else {
b.currentInterval = time.Duration(float64(b.currentInterval) * b.Multiplier)
}
}
// Returns a random value from the following interval:
// [randomizationFactor * currentInterval, randomizationFactor * currentInterval].
func getRandomValueFromInterval(randomizationFactor, random float64, currentInterval time.Duration) time.Duration {
var delta = randomizationFactor * float64(currentInterval)
var minInterval = float64(currentInterval) - delta
var maxInterval = float64(currentInterval) + delta
// Get a random value from the range [minInterval, maxInterval].
// The formula used below has a +1 because if the minInterval is 1 and the maxInterval is 3 then
// we want a 33% chance for selecting either 1, 2 or 3.
return time.Duration(minInterval + (random * (maxInterval - minInterval + 1)))
}

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@ -0,0 +1,108 @@
package backoff
import (
"math"
"testing"
"time"
)
func TestBackOff(t *testing.T) {
var (
testInitialInterval = 500 * time.Millisecond
testRandomizationFactor = 0.1
testMultiplier = 2.0
testMaxInterval = 5 * time.Second
testMaxElapsedTime = 15 * time.Minute
)
exp := NewExponentialBackOff()
exp.InitialInterval = testInitialInterval
exp.RandomizationFactor = testRandomizationFactor
exp.Multiplier = testMultiplier
exp.MaxInterval = testMaxInterval
exp.MaxElapsedTime = testMaxElapsedTime
exp.Reset()
var expectedResults = []time.Duration{500, 1000, 2000, 4000, 5000, 5000, 5000, 5000, 5000, 5000}
for i, d := range expectedResults {
expectedResults[i] = d * time.Millisecond
}
for _, expected := range expectedResults {
assertEquals(t, expected, exp.currentInterval)
// Assert that the next backoff falls in the expected range.
var minInterval = expected - time.Duration(testRandomizationFactor*float64(expected))
var maxInterval = expected + time.Duration(testRandomizationFactor*float64(expected))
var actualInterval = exp.NextBackOff()
if !(minInterval <= actualInterval && actualInterval <= maxInterval) {
t.Error("error")
}
}
}
func TestGetRandomizedInterval(t *testing.T) {
// 33% chance of being 1.
assertEquals(t, 1, getRandomValueFromInterval(0.5, 0, 2))
assertEquals(t, 1, getRandomValueFromInterval(0.5, 0.33, 2))
// 33% chance of being 2.
assertEquals(t, 2, getRandomValueFromInterval(0.5, 0.34, 2))
assertEquals(t, 2, getRandomValueFromInterval(0.5, 0.66, 2))
// 33% chance of being 3.
assertEquals(t, 3, getRandomValueFromInterval(0.5, 0.67, 2))
assertEquals(t, 3, getRandomValueFromInterval(0.5, 0.99, 2))
}
type TestClock struct {
i time.Duration
start time.Time
}
func (c *TestClock) Now() time.Time {
t := c.start.Add(c.i)
c.i += time.Second
return t
}
func TestGetElapsedTime(t *testing.T) {
var exp = NewExponentialBackOff()
exp.Clock = &TestClock{}
exp.Reset()
var elapsedTime = exp.GetElapsedTime()
if elapsedTime != time.Second {
t.Errorf("elapsedTime=%d", elapsedTime)
}
}
func TestMaxElapsedTime(t *testing.T) {
var exp = NewExponentialBackOff()
exp.Clock = &TestClock{start: time.Time{}.Add(10000 * time.Second)}
// Change the currentElapsedTime to be 0 ensuring that the elapsed time will be greater
// than the max elapsed time.
exp.startTime = time.Time{}
assertEquals(t, Stop, exp.NextBackOff())
}
func TestBackOffOverflow(t *testing.T) {
var (
testInitialInterval time.Duration = math.MaxInt64 / 2
testMaxInterval time.Duration = math.MaxInt64
testMultiplier = 2.1
)
exp := NewExponentialBackOff()
exp.InitialInterval = testInitialInterval
exp.Multiplier = testMultiplier
exp.MaxInterval = testMaxInterval
exp.Reset()
exp.NextBackOff()
// Assert that when an overflow is possible the current varerval time.Duration is set to the max varerval time.Duration .
assertEquals(t, testMaxInterval, exp.currentInterval)
}
func assertEquals(t *testing.T, expected, value time.Duration) {
if expected != value {
t.Errorf("got: %d, expected: %d", value, expected)
}
}

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