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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.

Demo

You can read the source code in example/main.go.

Todo

Vim mode
Transpose words
More funny examples

Usage

Simplest example

import "github.com/chzyer/readline"

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

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

Example with auto refresh

import (
	"log"
	"github.com/chzyer/readline"
)

rl, err := readline.New("> ")
if err != nil {
	panic(err)
}
defer rl.Close()
log.SetOutput(l.Stderr()) // let "log" write to l.Stderr instead of os.Stderr

go func() {
	for _ = range time.Tick(time.Second) {
		log.Println("hello")
	}
}()

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

Example with auto completion

import (
	"log"
	"github.com/chzyer/readline"
)

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

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

for {
	line, err := rl.Readline()
	if err != nil { // io.EOF
		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

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`	Clean screen (TODO)
`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 (TODO)
`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
Character	Move to next line
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

Feedback

If you have any question, please submit an GitHub Issues and any pull request is welcomed :)

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