readline

Readline is A Pure Go Implementation of a libreadline-style Library.
The goal is to be a powerful alternater for GNU-Readline.

WHY: Readline will support most of features which GNU Readline is supported, and provide a pure go environment and a MIT license.

It can also provides shell-like interactives by using flagly (demo: flagly-shell)

Demo

Also works fine in windows

example/readline-demo The source code about the demo above
example/readline-im Example for how to write a IM program.
example/readline-multiline Example for how to parse command which can submit by multiple time.
example/readline-pass-strength A example about checking password strength, written by @sahib

Todo

Vi Mode is not completely finish
More funny examples
Support dumb/eterm-color terminal in emacs

Features

Support emacs/vi mode, almost all basic features that GNU-Readline is supported
zsh-style backward/forward history search
zsh-style completion
Readline auto refresh when others write to Stdout while editing (it needs specify the Stdout/Stderr provided by *readline.Instance to others).
Support colourful prompt in all platforms.

Usage

Import package

go get gopkg.in/readline.v1

go get github.com/chzyer/readline

Simplest example

import "gopkg.in/readline.v1"

rl, err := readline.New("> ")
if err != nil {
	panic(err)
}
defer rl.Close()

for {
	line, err := rl.Readline()
	if err != nil { // io.EOF, readline.ErrInterrupt
		break
	}
	println(line)
}

Example with durable history

rl, err := readline.NewEx(&readline.Config{
	Prompt: "> ",
	HistoryFile: "/tmp/readline.tmp",
})
if err != nil {
	panic(err)
}
defer rl.Close()

for {
	line, err := rl.Readline()
	if err != nil { // io.EOF, readline.ErrInterrupt
		break
	}
	println(line)
}

Example with auto completion

import (
	"gopkg.in/readline.v1"
)

var completer = readline.NewPrefixCompleter(
	readline.PcItem("say",
		readline.PcItem("hello"),
		readline.PcItem("bye"),
	),
	readline.PcItem("help"),
)

rl, err := readline.NewEx(&readline.Config{
	Prompt:       "> ",
	AutoComplete: completer,
})
if err != nil {
	panic(err)
}
defer rl.Close()

for {
	line, err := rl.Readline()
	if err != nil { // io.EOF, readline.ErrInterrupt
		break
	}
	println(line)
}

Shortcut

Meta+B means press Esc and n separately.
Users can change that in terminal simulator(i.e. iTerm2) to Alt+B
Notice: Meta+B is equals with Alt+B in windows.

Shortcut in normal mode

Shortcut	Comment
`Ctrl`+`A`	Beginning of line
`Ctrl`+`B` / `←`	Backward one character
`Meta`+`B`	Backward one word
`Ctrl`+`C`	Send io.EOF
`Ctrl`+`D`	Delete one character
`Meta`+`D`	Delete one word
`Ctrl`+`E`	End of line
`Ctrl`+`F` / `→`	Forward one character
`Meta`+`F`	Forward one word
`Ctrl`+`G`	Cancel
`Ctrl`+`H`	Delete previous character
`Ctrl`+`I` / `Tab`	Command line completion
`Ctrl`+`J`	Line feed
`Ctrl`+`K`	Cut text to the end of line
`Ctrl`+`L`	Clear screen
`Ctrl`+`M`	Same as Enter key
`Ctrl`+`N` / `↓`	Next line (in history)
`Ctrl`+`P` / `↑`	Prev line (in history)
`Ctrl`+`R`	Search backwards in history
`Ctrl`+`S`	Search forwards in history
`Ctrl`+`T`	Transpose characters
`Meta`+`T`	Transpose words (TODO)
`Ctrl`+`U`	Cut text to the beginning of line
`Ctrl`+`W`	Cut previous word
`Backspace`	Delete previous character
`Meta`+`Backspace`	Cut previous word
`Enter`	Line feed

Shortcut in Search Mode (Ctrl+S or Ctrl+r to enter this mode)

Shortcut	Comment
`Ctrl`+`S`	Search forwards in history
`Ctrl`+`R`	Search backwards in history
`Ctrl`+`C` / `Ctrl`+`G`	Exit Search Mode and revert the history
`Backspace`	Delete previous character
Other	Exit Search Mode

Shortcut in Complete Select Mode (double Tab to enter this mode)

Shortcut	Comment
`Ctrl`+`F`	Move Forward
`Ctrl`+`B`	Move Backward
`Ctrl`+`N`	Move to next line
`Ctrl`+`P`	Move to previous line
`Ctrl`+`A`	Move to the first candicate in current line
`Ctrl`+`E`	Move to the last candicate in current line
`Tab` / `Enter`	Use the word on cursor to complete
`Ctrl`+`C` / `Ctrl`+`G`	Exit Complete Select Mode
Other	Exit Complete Select Mode

Tested with

Environment	$TERM
Mac OS X iTerm2	xterm
Mac OS X default Terminal.app	xterm
Mac OS X iTerm2 Screen	screen
Mac OS X iTerm2 Tmux	screen
Ubuntu Server 14.04 LTS	linux
Centos 7	linux
Windows 10	-

Notice:

Ctrl+A is not working in screen because it used as a control command by default

If you test it otherwhere, whether it works fine or not, please let me know!

Who is using Readline

Feedback

If you have any questions, please submit a github issue and any pull requests is welcomed :)

Backers

Love Readline? Help me keep it alive by donating funds to cover project expenses!
[Become a backer]

jcramb/readline