[example] Add a IM example

README.md

@@ -26,6 +26,10 @@ Also works fine in windows
 
 * [example/readline-demo](https://github.com/chzyer/readline/blob/master/example/readline-demo/readline-demo.go) The source code about the demo above
 
+* [example/readline-im](https://github.com/chzyer/readline/blob/master/example/readline-im/readline-im.go) Example for how to write a IM program.
+
+* [example/readline-multiline](https://github.com/chzyer/readline/blob/master/example/readline-multiline/readline-multiline.go) Example for how to parse command which can submit by multiple time.
+
 * [example/readline-pass-strength](https://github.com/chzyer/readline/blob/master/example/readline-pass-strength/readline-pass-strength.go) A example about checking password strength, written by [@sahib](https://github.com/sahib)
 
 # Todo

example/readline-im/readline-im.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"fmt"
+	"math/rand"
+	"time"
+
+	"github.com/chzyer/readline"
+)
+import "log"
+
+func main() {
+	rl, err := readline.NewEx(&readline.Config{
+		UniqueEditLine: true,
+	})
+	if err != nil {
+		panic(err)
+	}
+	defer rl.Close()
+
+	rl.SetPrompt("username: ")
+	username, err := rl.Readline()
+	if err != nil {
+		return
+	}
+	rl.ResetHistory()
+	log.SetOutput(rl.Stderr())
+
+	fmt.Fprintln(rl, "Hi,", username+"! My name is Dave.")
+	rl.SetPrompt(username + "> ")
+
+	done := make(chan struct{})
+	go func() {
+		rand.Seed(time.Now().Unix())
+	loop:
+		for {
+			select {
+			case <-time.After(time.Duration(rand.Intn(20)) * 100 * time.Millisecond):
+			case <-done:
+				break loop
+			}
+			log.Println("Dave:", "hello")
+		}
+		log.Println("Dave:", "bye")
+		done <- struct{}{}
+	}()
+
+	for {
+		ln := rl.Line()
+		if ln.CanContinue() {
+			continue
+		} else if ln.CanBreak() {
+			break
+		}
+		log.Println(username+":", ln.Line)
+	}
+	rl.Clean()
+	done <- struct{}{}
+	<-done
+}

history.go

@@ -37,6 +37,11 @@ func newOpHistory(cfg *Config) (o *opHistory) {
 	return o
 }
 
+func (o *opHistory) Reset() {
+	o.history = list.New()
+	o.current = nil
+}
+
 func (o *opHistory) IsHistoryClosed() bool {
 	return o.fd.Fd() == ^(uintptr(0))
 }

operation.go

@@ -237,11 +237,16 @@ func (o *Operation) ioloop() {
 			}
 
 			// treat as EOF
-			o.buf.WriteString(o.cfg.EOFPrompt + "\n")
+			if !o.cfg.UniqueEditLine {
+				o.buf.WriteString(o.cfg.EOFPrompt + "\n")
+			}
 			o.buf.Reset()
 			isUpdateHistory = false
 			o.history.Revert()
 			o.errchan <- io.EOF
+			if o.cfg.UniqueEditLine {
+				o.buf.Clean()
+			}
 		case CharInterrupt:
 			if o.IsSearchMode() {
 				o.t.KickRead()
@@ -257,9 +262,13 @@ func (o *Operation) ioloop() {
 			o.buf.MoveToLineEnd()
 			o.buf.Refresh(nil)
 			hint := o.cfg.InterruptPrompt + "\n"
-			o.buf.WriteString(hint)
+			if !o.cfg.UniqueEditLine {
+				o.buf.WriteString(hint)
+			}
 			remain := o.buf.Reset()
-			remain = remain[:len(remain)-len([]rune(hint))]
+			if !o.cfg.UniqueEditLine {
+				remain = remain[:len(remain)-len([]rune(hint))]
+			}
 			isUpdateHistory = false
 			o.history.Revert()
 			o.errchan <- &InterruptError{remain}
@@ -419,6 +428,10 @@ func (op *Operation) SetConfig(cfg *Config) (*Config, error) {
 	return old, nil
 }
 
+func (o *Operation) ResetHistory() {
+	o.history.Reset()
+}
+
 // if err is not nil, it just mean it fail to write to file
 // other things goes fine.
 func (o *Operation) SaveHistory(content string) error {
@@ -431,6 +444,10 @@ func (o *Operation) Refresh() {
 	}
 }
 
+func (o *Operation) Clean() {
+	o.buf.Clean()
+}
+
 func FuncListener(f func(line []rune, pos int, key rune) (newLine []rune, newPos int, ok bool)) Listener {
 	return &DumpListener{f: f}
 }

readline.go

@@ -140,6 +140,10 @@ func New(prompt string) (*Instance, error) {
 	return NewEx(&Config{Prompt: prompt})
 }
 
+func (i *Instance) ResetHistory() {
+	i.Operation.ResetHistory()
+}
+
 func (i *Instance) SetPrompt(s string) {
 	i.Operation.SetPrompt(s)
 }
@@ -189,6 +193,24 @@ func (i *Instance) ReadPassword(prompt string) ([]byte, error) {
 	return i.Operation.Password(prompt)
 }
 
+type Result struct {
+	Line  string
+	Error error
+}
+
+func (l *Result) CanContinue() bool {
+	return len(l.Line) != 0 && l.Error == ErrInterrupt
+}
+
+func (l *Result) CanBreak() bool {
+	return !l.CanContinue() && l.Error != nil
+}
+
+func (i *Instance) Line() *Result {
+	ret, err := i.Readline()
+	return &Result{ret, err}
+}
+
 // err is one of (nil, io.EOF, readline.ErrInterrupt)
 func (i *Instance) Readline() (string, error) {
 	return i.Operation.String()
@@ -211,6 +233,9 @@ func (i *Instance) Close() error {
 	i.Operation.Close()
 	return nil
 }
+func (i *Instance) Clean() {
+	i.Operation.Clean()
+}
 
 func (i *Instance) Write(b []byte) (int, error) {
 	return i.Stdout().Write(b)

runebuf.go

@@ -20,9 +20,9 @@ type RuneBuffer struct {
 	prompt []rune
 	w      io.Writer
 
-	cleanInScreen bool
-	interactive   bool
-	cfg           *Config
+	hadClean    bool
+	interactive bool
+	cfg         *Config
 
 	width int
 
@@ -374,7 +374,7 @@ func (r *RuneBuffer) Refresh(f func()) {
 
 func (r *RuneBuffer) print() {
 	r.w.Write(r.output())
-	r.cleanInScreen = false
+	r.hadClean = false
 }
 
 func (r *RuneBuffer) output() []byte {
@@ -472,9 +472,9 @@ func (r *RuneBuffer) Clean() {
 }
 
 func (r *RuneBuffer) clean(idxLine int) {
-	if r.cleanInScreen || !r.interactive {
+	if r.hadClean || !r.interactive {
 		return
 	}
-	r.cleanInScreen = true
+	r.hadClean = true
 	r.cleanOutput(r.w, idxLine)
 }