package readline import ( "bufio" "fmt" "io" "os" "syscall" ) type Prompt struct { Prompt string AltPrompt string Placeholder string AltPlaceholder string UseAlt bool } type Terminal struct { outchan chan rune } type Instance struct { Prompt *Prompt Terminal *Terminal History *History } func New(prompt Prompt) (*Instance, error) { term, err := NewTerminal() if err != nil { return nil, err } history, err := NewHistory() if err != nil { return nil, err } return &Instance{ Prompt: &prompt, Terminal: term, History: history, }, nil } func (i *Instance) Readline() (string, error) { prompt := i.Prompt.Prompt if i.Prompt.UseAlt { prompt = i.Prompt.AltPrompt } fmt.Print(prompt) termios, err := SetRawMode(syscall.Stdin) if err != nil { return "", err } defer UnsetRawMode(syscall.Stdin, termios) buf, _ := NewBuffer(i.Prompt) var esc bool var escex bool var metaDel bool var pasteMode PasteMode var currentLineBuf []rune for { if buf.IsEmpty() { ph := i.Prompt.Placeholder if i.Prompt.UseAlt { ph = i.Prompt.AltPlaceholder } fmt.Printf(ColorGrey + ph + fmt.Sprintf(CursorLeftN, len(ph)) + ColorDefault) } r, err := i.Terminal.Read() if buf.IsEmpty() { fmt.Print(ClearToEOL) } if err != nil { return "", io.EOF } if escex { escex = false switch r { case KeyUp: if i.History.Pos > 0 { if i.History.Pos == i.History.Size() { currentLineBuf = []rune(buf.String()) } buf.Replace(i.History.Prev()) } case KeyDown: if i.History.Pos < i.History.Size() { buf.Replace(i.History.Next()) if i.History.Pos == i.History.Size() { buf.Replace(currentLineBuf) } } case KeyLeft: buf.MoveLeft() case KeyRight: buf.MoveRight() case CharBracketedPaste: var code string for cnt := 0; cnt < 3; cnt++ { r, err = i.Terminal.Read() if err != nil { return "", io.EOF } code += string(r) } if code == CharBracketedPasteStart { pasteMode = PasteModeStart } else if code == CharBracketedPasteEnd { pasteMode = PasteModeEnd } case KeyDel: if buf.Size() > 0 { buf.Delete() } metaDel = true case MetaStart: buf.MoveToStart() case MetaEnd: buf.MoveToEnd() default: // skip any keys we don't know about continue } continue } else if esc { esc = false switch r { case 'b': buf.MoveLeftWord() case 'f': buf.MoveRightWord() case CharEscapeEx: escex = true } continue } switch r { case CharNull: continue case CharEsc: esc = true case CharInterrupt: return "", ErrInterrupt case CharLineStart: buf.MoveToStart() case CharLineEnd: buf.MoveToEnd() case CharBackward: buf.MoveLeft() case CharForward: buf.MoveRight() case CharBackspace, CharCtrlH: buf.Remove() case CharTab: // todo: convert back to real tabs for cnt := 0; cnt < 8; cnt++ { buf.Add(' ') } case CharDelete: if buf.Size() > 0 { buf.Delete() } else { return "", io.EOF } case CharKill: buf.DeleteRemaining() case CharCtrlU: buf.DeleteBefore() case CharCtrlL: buf.ClearScreen() case CharCtrlW: buf.DeleteWord() case CharEnter: output := buf.String() if output != "" { i.History.Add([]rune(output)) } buf.MoveToEnd() fmt.Println() switch pasteMode { case PasteModeStart: output = `"""` + output case PasteModeEnd: output = output + `"""` } return output, nil default: if metaDel { metaDel = false continue } if r >= CharSpace || r == CharEnter { buf.Add(r) } } } } func (i *Instance) HistoryEnable() { i.History.Enabled = true } func (i *Instance) HistoryDisable() { i.History.Enabled = false } func NewTerminal() (*Terminal, error) { t := &Terminal{ outchan: make(chan rune), } go t.ioloop() return t, nil } func (t *Terminal) ioloop() { buf := bufio.NewReader(os.Stdin) for { r, _, err := buf.ReadRune() if err != nil { close(t.outchan) break } t.outchan <- r } } func (t *Terminal) Read() (rune, error) { r, ok := <-t.outchan if !ok { return 0, io.EOF } return r, nil }