led

package module
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 Go to latest Published: Jun 24, 2018 License: MIT Imports: 5 Imported by: 0

README

Led

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A line editor in Go. Inspired by linenoise, but written with extensibility and separation of concerns in mind.

The motivation behind this library is to provide line editor functionality that can be controlled, extended, and modified by clients with regards to how to handle key events. In this regard the name of the library also is a pun on letting go (of control).

Usage

import (
	"github.com/svenfuchs/led"
)

func main() {
	e := NewEd("$ ").Run()
	e.Handle(led.Chars, func(e *led.Ed, k led.Key) { ... })
	e.Run()
}

See example/led.go for a usage example that makes use of custom key handlers, suggestions, completion, and history, and reimplements (most of?) the functionality in linenoise.

Also see https://github.com/svenfuchs/travis-go for an example that takes over more control.

Todo

  • Handle multiple lines if line length exceeds terminal width
  • History search with ctrl-r

Documentation

Index

Constants

View Source 
const (
	Clear int = iota
	ClearLine
	Cursor
	ShowCursor
	HideCursor
	Del
	Cr
	Newline
	Red
	Green
	Reset
)

Known ansi codes

View Source 
const (
	Rgt int = iota
	Lft
)

Directions

View Source 
const (
	Chars int = iota
	CtrlA
	CtrlB
	CtrlC
	CtrlD
	CtrlE
	CtrlF
	CtrlH
	Tab
	CtrlK
	CtrlL
	Enter
	CtrlN
	CtrlP
	CtrlT
	CtrlU
	CtrlW
	Esc
	Backspace
	Delete
	ShiftTab
	Up
	Down
	Right
	Left
)

Known keys

View Source 
const (
	Forw int = iota
	Back
	Hist
	Comp
	Sugg
)

Forw/Back - directions Hist/Comp/Sugg - modes for cycling through sets

Variables

View Source 
var Keys = map[int]Key{
	CtrlA:     {CtrlA, []byte{0x1}, "Ctrl-A"},
	CtrlB:     {CtrlB, []byte{0x2}, "Ctrl-B"},
	CtrlC:     {CtrlC, []byte{0x3}, "Ctrl-C"},
	CtrlD:     {CtrlD, []byte{0x4}, "Ctrl-D"},
	CtrlE:     {CtrlE, []byte{0x5}, "Ctrl-E"},
	CtrlF:     {CtrlF, []byte{0x6}, "Ctrl-F"},
	CtrlH:     {CtrlH, []byte{0x8}, "Ctrl-H"},
	Tab:       {Tab, []byte{0x9}, "Tab"},
	CtrlK:     {CtrlK, []byte{0x0b}, "Ctrl-K"},
	CtrlL:     {CtrlL, []byte{0x0c}, "Ctrl-L"},
	Enter:     {Enter, []byte{0x0d}, "Enter"},
	CtrlN:     {CtrlN, []byte{0x0e}, "Ctrl-N"},
	CtrlP:     {CtrlP, []byte{0x10}, "Ctrl-P"},
	CtrlT:     {CtrlT, []byte{0x14}, "Ctrl-T"},
	CtrlU:     {CtrlU, []byte{0x15}, "Ctrl-U"},
	CtrlW:     {CtrlW, []byte{0x17}, "Ctrl-W"},
	Esc:       {Esc, []byte{0x1b}, "Esc"},
	Backspace: {Backspace, []byte{0x7f}, "Backspace"},
	Delete:    {Delete, []byte{0x1b, 0x5b, 0x33, 0x7E}, "Delete"},
	ShiftTab:  {ShiftTab, []byte{0x1b, 0x5b, 0x5a}, "Shift-Tab"},
	Up:        {Up, []byte{0x1b, 0x5b, 0x41}, "Up"},
	Down:      {Down, []byte{0x1b, 0x5b, 0x42}, "Down"},
	Right:     {Right, []byte{0x1b, 0x5b, 0x43}, "Right"},
	Left:      {Left, []byte{0x1b, 0x5b, 0x44}, "Left"},
}

Keys defines known keys

Functions

func Ansi 

func Ansi(c int) []byte

Ansi returns the chars for a given ansi code

func Colored 

func Colored(c int, b []byte) []byte

Colored returns the given chars wrapped in color codes

func Deansi 

func Deansi(b []byte) []byte

Deansi replaces ansi codes in the given byte array with hints. This is useful for testing.

func MoveCursor 

func MoveCursor(pos int, d int) []byte

MoveCursor returns ansi codes for moving the cursor by the given number of chars in the given direction.

func Read 

func Read(tty reader) chan Key

Read returns a channel for reading keys. Terminates on ctrl-d.

func SetCursor 

func SetCursor(pos int) []byte

SetCursor returns ansi codes for setting the cursor to the given horizontal position.

Types

type Code 

type Code struct {
	Code  int
	Chars []byte
	Hint  string
}

Code represents an ansi code

func (Code) Str 

func (c Code) Str() string

Str returns the ansi code's chars as a string

type Ed 

type Ed struct {
	Prompt    []byte
	Pos       int
	Chars     []byte
	Suggested []byte
	// contains filtered or unexported fields
}

Ed represents the line editor

func NewEd 

func NewEd(led string, t ...Iterm) *Ed

NewEd creates a line editor (Ed) without any handlers attached. See NewReadline for a line editor that resembles (most of) Linenoise's functionality.

func NewReadline 

func NewReadline(led string, t ...Iterm) *Ed

NewReadline creates a line editor that resembles most of Linenoise's functionality

func (*Ed) Append 

func (e *Ed) Append(b []byte)

Append appends the given chars at the end of the line.

func (*Ed) Back 

func (e *Ed) Back()

Back removes one char before the current cursor position.

func (*Ed) BackWord 

func (e *Ed) BackWord()

BackWord removes one word before the current cursor position.

func (*Ed) Complete 

func (e *Ed) Complete(strs [][]byte, dir int)

Complete displays the previous or next completion from the given slice depending on the given direction.

func (*Ed) CompleteNext 

func (e *Ed) CompleteNext(strs [][]byte)

CompleteNext displays the next completion from the given slice.

func (*Ed) CompletePrev 

func (e *Ed) CompletePrev(strs [][]byte)

CompletePrev displays the previous completion from the given slice.

func (*Ed) Del 

func (e *Ed) Del(i ...int)

Del writes a delete char (`\x7F`) to the terminae.

func (*Ed) Delete 

func (e *Ed) Delete()

Delete removes one char after the current cursor position.

func (*Ed) DeleteFromCursor 

func (e *Ed) DeleteFromCursor()

DeleteFromCursor deletes all chars from the current cursor position to the end of the line.

func (*Ed) Discard 

func (e *Ed) Discard()

Discard discards the given input by moving to the next line and starting over with an empty prompt. This resembles the behaviour Ctrl-C in Bash or Zshele.

func (*Ed) End 

func (e *Ed) End()

End moves the cursor to the end of the line.

func (*Ed) Handle 

func (e *Ed) Handle(key int, handler func(*Ed, Key))

Handle attaches a handler for a key

func (*Ed) History 

func (e *Ed) History(strs [][]byte, dir int)

History displays the previous or next line from the given slice depending on the given direction.

func (*Ed) HistoryNext 

func (e *Ed) HistoryNext(strs [][]byte)

HistoryNext displays the next line from the given slice.

func (*Ed) HistoryPrev 

func (e *Ed) HistoryPrev(strs [][]byte)

HistoryPrev displays the previous line from the given slice.

func (*Ed) Insert 

func (e *Ed) Insert(b []byte)

Insert inserts the given chars at the current cursor position.

func (*Ed) Left 

func (e *Ed) Left()

Left moves the cursor one char to the left.

func (*Ed) MoveCursor 

func (e *Ed) MoveCursor(i int, dir int)

MoveCursor moves the cursor by the given number of chars in the given direction.

func (*Ed) Newline 

func (e *Ed) Newline()

Newline writes a newline char to the terminae.

func (*Ed) Pause 

func (e *Ed) Pause()

Pause pauses the editor, should be used before outputting text to the terminal, e.g. in an Enter handler.

func (*Ed) Refresh 

func (e *Ed) Refresh()

func (*Ed) Reject 

func (e *Ed) Reject(chars []byte)

Reject rejects the given chars by printing them at the current cursor position in red, and removing them after 100 milliseconds.

func (*Ed) Reset 

func (e *Ed) Reset()

Reset resets the editor and starts over with an empty line.

func (*Ed) Resume 

func (e *Ed) Resume()

Resume resumes the editor, and places the terminal in raw mode.

func (*Ed) Return 

func (e *Ed) Return()

Return moves the cursor to the beginning of the line.

func (*Ed) Right 

func (e *Ed) Right()

Right moves the cursor one char to the right.

func (*Ed) Run 

func (e *Ed) Run()

Run runs the editor

func (*Ed) Set 

func (e *Ed) Set(b []byte)

Set sets the content of the editor to the given line.

func (*Ed) SetCursor 

func (e *Ed) SetCursor(pos ...int)

SetCursor sets the cursor to the given position, defaults to the current position.

func (*Ed) Stop 

func (e *Ed) Stop()

Stop stops the terminae.

func (*Ed) Str 

func (e *Ed) Str() string

Str returns the current line.

func (*Ed) Suggest 

func (e *Ed) Suggest(str []byte)

Suggest appends the first matching suggestion from the given slice in green after the current cursor position.

func (*Ed) Transpose 

func (e *Ed) Transpose()

Transpose transposes the char before the cursor position with the one on the cursor position, and moves the cursor one char to the right, if possible. If the cursor is at the beginning of the line it transposes the current char with the next one, and moves the cursor two chars to the right. This resembles Zshell's behaviour.

func (*Ed) Write 

func (e *Ed) Write(b []byte)

Write writes the given chars to the terminae.

type Iterm 

type Iterm interface {
	Start()
	Read(b []byte) (int, error)
	Write(b []byte) (int, error)
	Restore() error
	RawMode() error
	Close() error
}

Iterm represents a subset of the tty implemented in github.com/pkg/term.

type Key 

type Key struct {
	Code  int
	Chars []byte
	Name  string
}

Key represents a key

func (Key) Str 

func (k Key) Str() string

Str returns the key's chars as a string

type List 

type List struct {
	// contains filtered or unexported fields
}

List represents a list of strings that are used for completion, history, and suggestions.

func NewList 

func NewList(strs [][]byte, str []byte, mode int) *List

NewList returns a list of strings that are used for completion, history, and suggestions.

func (*List) Next 

func (c *List) Next() []byte

Next returns the next string from the list.

func (*List) Prev 

func (c *List) Prev() []byte

Prev returns the previous string from the list.

type Term 

type Term struct {
	// contains filtered or unexported fields
}

Term represents a terminal

func StartTerm 

func StartTerm(ts ...Iterm) *Term

StartTerm starts a terminal.

func (*Term) Clear 

func (t *Term) Clear()

Clear clears from the current cursor position to the end of the line.

func (*Term) ClearLine 

func (t *Term) ClearLine()

ClearLine clears the current line.

func (*Term) Del 

func (t *Term) Del(i ...int)

Del writes the given number of delete chars (`\x7F`) to the terminal (defaults to 1), deleting the char after the cursor position.

func (*Term) HideCursor 

func (t *Term) HideCursor()

HideCursor hides the cursor.

func (*Term) MoveCursor 

func (t *Term) MoveCursor(i int, dir int)

MoveCursor moves the cursor by the given number of chars in the given direction.

func (*Term) Newline 

func (t *Term) Newline()

Newline writes a newline char to the terminal.

func (*Term) Pause 

func (t *Term) Pause()

Pause pauses the terminal, restoring the previous mode and settings.

func (*Term) Read 

func (t *Term) Read() chan Key

Read returns a channel for reading keys from the terminal. See keys.Read.

func (*Term) Resume 

func (t *Term) Resume()

Resume resumes the terminal, setting the terminal in raw mode.

func (*Term) Return 

func (t *Term) Return()

Return writes a carriage return char to the terminal.

func (*Term) SetCursor 

func (t *Term) SetCursor(pos int)

SetCursor moves the cursor to the given horizontal position.

func (*Term) ShowCursor 

func (t *Term) ShowCursor()

ShowCursor shows the cursor.

func (*Term) Stop 

func (t *Term) Stop()

Stop stops the terminal, restoring the previous mode and settings, and closing the tty.

func (*Term) Write 

func (t *Term) Write(b []byte)

Write writes the given chars to the terminal.

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