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