Readline

Shell library with modern and simple UI features

This library is a modern, pure Go readline implementation, enhanced with editing and user interface features commonly found in modern shells, all in little more than 10K lines of code. Its kemap-based model and completion engine is heavily inspired from the Z-Shell architecture. It is used, between others, to power the console library.

Features

Editing

• Near-native Emacs and Vim modes.
• Configurable bind keymaps, with live reload and sane defaults.
• Extended list of edition/movement/control widgets (Emacs and Vim).
• Extended surround select/change/add fonctionality, with highlighting.
• Keywords switching (operators, booleans, hex/binary/digit) with iterations.
• Support for Vim Visual/Operator pending mode & cursor styles indications.
• Vim Insert and Replace (once/many).
• Many Vim text objects.
• All Vim registers, with completion support.
• Undo/redo history.
• Command-line edition in $EDITOR.
• Support for an arbitrary number of history sources.

Interface

• Support for most of oh-my-posh prompts (PS1/PS2/RPROMPT/transient/tooltip).
• Extended completion system, keymap-based and configurable, easy to populate & use.
• Multiple completion display styles, with color support.
• Completion & History incremental search system & highlighting (fuzzy-search).
• Automatic & context-aware suffix removal for efficient flags/path/list completion.
• Optional asynchronous autocomplete.
• Usage/hint message display.
• Support for syntax highlighting

Documentation

Readline is used by the console library and its example binary. To get a grasp of the functionality provided by readline and its default configuration, install and start the binary.

• Introduction
• Configuration file
• Keymaps & Widgets
• Prompts
• History Sources
• Vim mode
• Custom callbacks
• Completions & Hints
• Other features

Showcases

- Emacs edition

(This extract is quite a pity, because its author is not using Emacs and does not know many of its shortcuts)

- Vim edition

- Undo/redo line history

- Keyword switching

- Vim selection & movements (basic)

- Vim surround (selection and change)

Basic surround selection changes/adds

Surround and change in shellwords, matching brackets, etc.

- Vim registers (with completion)

- History movements/completion/use/search

History movement, completion and some other other widgets

History cycling and search

- Completion

Classic mode & incremental search mode

Smart terminal estate management

- Suffix autoremoval

- Prompts

- Logging

- Configuration hot-reload

Status

This library is in a pre-release status, although pretending to be quite bug-free as compared to its feature set. Please open a PR or an issue if you wish to bring enhancements to it. Other contributions, as well as bug fixes and reviews are also welcome.

Credits

• While most of the code has been rewritten from scratch, the original library used is lmorg/readline. I would have never ventured myself doing this if he had not ventured writing a Vim mode core in the first place.
• Some of the Vim code is inspired or translated from zsh-vi-mode.