add readpassword

example/main.go

@@ -12,6 +12,7 @@ import (
 
 func usage(w io.Writer) {
 	io.WriteString(w, `
+login
 setprompt <prompt>
 say <hello>
 bye
@@ -19,6 +20,7 @@ bye
 }
 
 var completer = readline.NewPrefixCompleter(
+	readline.PcItem("login"),
 	readline.PcItem("say",
 		readline.PcItem("hello"),
 		readline.PcItem("bye"),
@@ -52,6 +54,12 @@ func main() {
 		}
 
 		switch {
+		case line == "login":
+			pswd, err := l.ReadPassword("please enter your password: ")
+			if err != nil {
+				break
+			}
+			println("you enter:", strconv.Quote(string(pswd)))
 		case line == "help":
 			usage(l.Stderr())
 		case strings.HasPrefix(line, "setprompt"):

operation.go

@@ -1,6 +1,12 @@
 package readline
 
-import "io"
+import (
+	"fmt"
+	"io"
+	"os"
+
+	"golang.org/x/crypto/ssh/terminal"
+)
 
 type Operation struct {
 	cfg     *Config
@@ -240,6 +246,16 @@ func (o *Operation) Runes() ([]rune, error) {
 	return r, nil
 }
 
+func (o *Operation) Password(prompt string) ([]byte, error) {
+	w := o.Stdout()
+	if prompt != "" {
+		fmt.Fprintf(w, prompt)
+	}
+	b, err := terminal.ReadPassword(int(os.Stdin.Fd()))
+	fmt.Fprint(w, "\r\n")
+	return b, err
+}
+
 func (o *Operation) SetTitle(t string) {
 	o.w.Write([]byte("\033[2;" + t + "\007"))
 }

readline.go

@@ -59,6 +59,10 @@ func (i *Instance) Stderr() io.Writer {
 	return i.o.Stderr()
 }
 
+func (i *Instance) ReadPassword(prompt string) ([]byte, error) {
+	return i.o.Password(prompt)
+}
+
 func (i *Instance) Readline() (string, error) {
 	return i.o.String()
 }