add simple vim mode

README.md

@@ -24,7 +24,7 @@ You can read the source code in [example/main.go](https://github.com/chzyer/read
 
 # Todo
 
-* Vim mode
+* Vim mode (WIP)
 * More funny examples
 * Support dumb/eterm-color terminal in emacs
 
@@ -199,6 +199,16 @@ Notice: `Meta`+`B` is equals with `Alt`+`B` in windows.
 | `Ctrl`+`C` / `Ctrl`+`G` | Exit Complete Select Mode                   |
 | Other                   | Exit Complete Select Mode                   |
 
+* Vim Mode (set Config.VimMode to true)
+
+| Mode   | Shortcut | Comment                                     |
+|--------+----------+---------------------------------------------|
+| Normal | `j`      | Next line (in history)                      |
+|        | `k`      | Prev line (in history)                      |
+|        | `h`      | Move Backward                               |
+|        | `l`      | Move Forward                                |
+
+
 # Tested with
 
 | Environment                   | $TERM  |

char.go

@@ -7,7 +7,7 @@ const (
 	CharDelete    = 4
 	CharLineEnd   = 5
 	CharForward   = 6
-	CharCancel    = 7
+	CharBell      = 7
 	CharCtrlH     = 8
 	CharTab       = 9
 	CharCtrlJ     = 10
@@ -26,8 +26,8 @@ const (
 )
 
 const (
-	MetaPrev rune = -iota - 1
+	MetaBackward rune = -iota - 1
-	MetaNext
+	MetaForward
 	MetaDelete
 	MetaBackspace
 	MetaTranspose

complete.go

@@ -127,7 +127,7 @@ func (o *opCompleter) HandleCompleteSelect(r rune) bool {
 		next = false
 	case CharTab, CharForward:
 		o.doSelect()
-	case CharCancel, CharInterrupt:
+	case CharBell, CharInterrupt:
 		o.ExitCompleteMode(true)
 		next = false
 	case CharNext:

example/main.go

@@ -40,6 +40,7 @@ func main() {
 		Prompt:       "\033[31m»\033[0m ",
 		HistoryFile:  "/tmp/readline.tmp",
 		AutoComplete: completer,
+		// VimMode:      true,
 	})
 	if err != nil {
 		panic(err)

operation.go

@@ -18,6 +18,7 @@ type Operation struct {
 	*opHistory
 	*opSearch
 	*opCompleter
+	*opVim
 }
 
 type wrapWriter struct {
@@ -56,6 +57,7 @@ func NewOperation(t *Terminal, cfg *Config) *Operation {
 		outchan:   make(chan []rune),
 		opHistory: newOpHistory(cfg.HistoryFile),
 	}
+	op.opVim = newVimMode(op)
 	op.w = op.buf.w
 	op.opSearch = newOpSearch(op.buf.w, op.buf, op.opHistory)
 	op.opCompleter = newOpCompleter(op.buf.w, op)
@@ -87,13 +89,21 @@ func (o *Operation) ioloop() {
 			case CharInterrupt:
 				o.t.KickRead()
 				fallthrough
-			case CharCancel:
+			case CharBell:
+				continue
+			}
+		}
+
+		if o.IsEnableVimMode() {
+			var ok bool
+			r, ok = o.HandleVim(r, o.t.ReadRune)
+			if ok {
 				continue
 			}
 		}
 
 		switch r {
-		case CharCancel:
+		case CharBell:
 			if o.IsSearchMode() {
 				o.ExitSearchMode(true)
 				o.buf.Refresh(nil)
@@ -119,11 +129,11 @@ func (o *Operation) ioloop() {
 		case CharKill:
 			o.buf.Kill()
 			keepInCompleteMode = true
-		case MetaNext:
+		case MetaForward:
 			o.buf.MoveToNextWord()
 		case CharTranspose:
 			o.buf.Transpose()
-		case MetaPrev:
+		case MetaBackward:
 			o.buf.MoveToPrevWord()
 		case MetaDelete:
 			o.buf.DeleteWord()
@@ -132,7 +142,9 @@ func (o *Operation) ioloop() {
 		case CharLineEnd:
 			o.buf.MoveToLineEnd()
 		case CharDelete:
-			o.buf.Delete()
+			if !o.buf.Delete() {
+				o.t.Bell()
+			}
 		case CharBackspace, CharCtrlH:
 			if o.IsSearchMode() {
 				o.SearchBackspace()
@@ -141,6 +153,7 @@ func (o *Operation) ioloop() {
 			}
 
 			if o.buf.Len() == 0 {
+				o.t.Bell()
 				break
 			}
 			o.buf.Backspace()
@@ -167,11 +180,15 @@ func (o *Operation) ioloop() {
 			buf := o.PrevHistory()
 			if buf != nil {
 				o.buf.Set(buf)
+			} else {
+				o.t.Bell()
 			}
 		case CharNext:
 			buf, ok := o.NextHistory()
 			if ok {
 				o.buf.Set(buf)
+			} else {
+				o.t.Bell()
 			}
 		case CharInterrupt:
 			if o.IsSearchMode() {

readline.go

@@ -11,6 +11,7 @@ type Config struct {
 	Prompt       string
 	HistoryFile  string
 	AutoComplete AutoCompleter
+	VimMode      bool
 	Stdout       io.Writer
 	Stderr       io.Writer
 
@@ -59,6 +60,10 @@ func (i *Instance) Stderr() io.Writer {
 	return i.o.Stderr()
 }
 
+func (i *Instance) SetVimMode(on bool) {
+	i.o.SetVimMode(on)
+}
+
 func (i *Instance) ReadPassword(prompt string) ([]byte, error) {
 	return i.o.Password(prompt)
 }

runebuf.go

@@ -98,13 +98,15 @@ func (r *RuneBuffer) MoveForward() {
 	})
 }
 
-func (r *RuneBuffer) Delete() {
+func (r *RuneBuffer) Delete() (success bool) {
 	r.Refresh(func() {
 		if r.idx == len(r.buf) {
 			return
 		}
 		r.buf = append(r.buf[:r.idx], r.buf[r.idx+1:]...)
+		success = true
 	})
+	return
 }
 
 func (r *RuneBuffer) DeleteWord() {
@@ -126,7 +128,7 @@ func (r *RuneBuffer) DeleteWord() {
 	r.Kill()
 }
 
-func (r *RuneBuffer) MoveToPrevWord() {
+func (r *RuneBuffer) MoveToPrevWord() (success bool) {
 	r.Refresh(func() {
 		if r.idx == 0 {
 			return
@@ -135,11 +137,14 @@ func (r *RuneBuffer) MoveToPrevWord() {
 		for i := r.idx - 1; i > 0; i-- {
 			if !IsWordBreak(r.buf[i]) && IsWordBreak(r.buf[i-1]) {
 				r.idx = i
+				success = true
 				return
 			}
 		}
 		r.idx = 0
+		success = true
 	})
+	return
 }
 
 func (r *RuneBuffer) KillFront() {
@@ -237,6 +242,35 @@ func (r *RuneBuffer) LineCount() int {
 	return LineCount(RunesWidth(r.buf) + r.PromptLen())
 }
 
+func (r *RuneBuffer) MoveTo(ch rune, prevChar, reverse bool) (success bool) {
+	r.Refresh(func() {
+		if reverse {
+			for i := r.idx - 1; i >= 0; i-- {
+				if r.buf[i] == ch {
+					r.idx = i
+					if prevChar {
+						r.idx++
+					}
+					success = true
+					return
+				}
+			}
+			return
+		}
+		for i := r.idx + 1; i < len(r.buf); i++ {
+			if r.buf[i] == ch {
+				r.idx = i
+				if prevChar {
+					r.idx--
+				}
+				success = true
+				return
+			}
+		}
+	})
+	return
+}
+
 func (r *RuneBuffer) IdxLine() int {
 	totalWidth := RunesWidth(r.buf[:r.idx]) + r.PromptLen()
 	w := getWidth()

terminal.go

@@ -113,6 +113,10 @@ func (t *Terminal) ioloop() {
 		expectNextChar = true
 		switch r {
 		case CharEsc:
+			if t.cfg.VimMode {
+				t.outchan <- r
+				break
+			}
 			isEscape = true
 		case CharInterrupt, CharEnter, CharCtrlJ:
 			expectNextChar = false
@@ -123,6 +127,10 @@ func (t *Terminal) ioloop() {
 	}
 }
 
+func (t *Terminal) Bell() {
+	fmt.Fprintf(t, "%c", CharBell)
+}
+
 func (t *Terminal) Close() error {
 	if atomic.SwapInt64(&t.closed, 1) != 0 {
 		return nil

utils.go

@@ -57,9 +57,9 @@ func escapeExKey(r rune) rune {
 func escapeKey(r rune) rune {
 	switch r {
 	case 'b':
-		r = MetaPrev
+		r = MetaBackward
 	case 'f':
-		r = MetaNext
+		r = MetaForward
 	case 'd':
 		r = MetaDelete
 	case CharTranspose:

vim.go

@@ -0,0 +1,144 @@
+package readline
+
+const (
+	VIM_NORMAL = iota
+	VIM_INSERT
+	VIM_VISUAL
+)
+
+type opVim struct {
+	cfg     *Config
+	op      *Operation
+	vimMode int
+}
+
+func newVimMode(op *Operation) *opVim {
+	ov := &opVim{
+		cfg: op.cfg,
+		op:  op,
+	}
+	ov.SetVimMode(ov.cfg.VimMode)
+	return ov
+}
+
+func (o *opVim) SetVimMode(on bool) {
+	if o.cfg.VimMode && !on { // turn off
+		o.ExitVimMode()
+	}
+	o.cfg.VimMode = on
+	o.vimMode = VIM_INSERT
+}
+
+func (o *opVim) ExitVimMode() {
+	o.vimMode = VIM_NORMAL
+}
+
+func (o *opVim) IsEnableVimMode() bool {
+	return o.cfg.VimMode
+}
+
+func (o *opVim) HandleVimNormal(r rune, readNext func() rune) (t rune, handle bool) {
+	switch r {
+	case CharEnter, CharInterrupt:
+		return r, false
+	}
+	rb := o.op.buf
+	handled := true
+	{
+		switch r {
+		case 'h':
+			t = CharBackward
+		case 'j':
+			t = CharNext
+		case 'k':
+			t = CharPrev
+		case 'l':
+			t = CharForward
+		default:
+			handled = false
+		}
+		if handled {
+			return t, false
+		}
+	}
+
+	{ // to insert
+		handled = true
+		switch r {
+		case 'i':
+		case 'I':
+			rb.MoveToLineStart()
+		case 'a':
+			rb.MoveForward()
+		case 'A':
+			rb.MoveToLineEnd()
+		case 's':
+			rb.Delete()
+		default:
+			handled = false
+		}
+		if handled {
+			o.EnterVimInsertMode()
+			return r, true
+		}
+	}
+
+	{ // movement
+		handled = true
+		switch r {
+		case '0', '^':
+			rb.MoveToLineStart()
+		case '$':
+			rb.MoveToLineEnd()
+		case 'b':
+			rb.MoveToPrevWord()
+		case 'w':
+			rb.MoveToNextWord()
+		case 'f', 'F', 't', 'T':
+			next := readNext()
+			prevChar := r == 't' || r == 'T'
+			reverse := r == 'F' || r == 'T'
+			switch next {
+			case CharEsc:
+			default:
+				if rb.MoveTo(next, prevChar, reverse) {
+					return r, true
+				}
+			}
+		default:
+			handled = false
+		}
+		if handled {
+			return r, true
+		}
+	}
+
+	// invalid operation
+	o.op.t.Bell()
+	return r, true
+}
+
+func (o *opVim) EnterVimInsertMode() {
+	o.vimMode = VIM_INSERT
+}
+
+func (o *opVim) ExitVimInsertMode() {
+	o.vimMode = VIM_NORMAL
+}
+
+func (o *opVim) HandleVim(r rune, readNext func() rune) (rune, bool) {
+	if o.vimMode == VIM_NORMAL {
+		return o.HandleVimNormal(r, readNext)
+	}
+	if r == CharEsc {
+		o.ExitVimInsertMode()
+		return r, true
+	}
+
+	switch o.vimMode {
+	case VIM_INSERT:
+		return r, false
+	case VIM_VISUAL:
+	}
+	return r, false
+}