key-assist.el - keybinding cheatsheet / launcher

Commentary:

For Emacs users:

This package provides an interactive command to easily produce a keybinding cheat-sheet "on-the-fly", and then to launch any command on the cheat-sheet list. At its simplest, it gives the user a list of keybindings for commands specific to the current buffer's major-mode, but it's trivially simple to ask it to build an alternative (see below, section 'Interactive operation').

💡 Think of the default-action as an improved C-h m summary.

🏁 Enter a command substring to see all related bindings.

Use this package to: learn keybindings; learn what commands are available specifically for the current buffer; run a command from a descriptive list; and afterwards return to work quickly.

For Emacs programmers:

This package provides a simple, flexible way to produce custom keybinding cheat-sheets and command launchers for sets of commands, with each command being described, along with its direct keybinding for direct use without the launcher (see below).

For everyone:

If you've ever used packages such as ivy or magit, you've probably benefited from each's custom combination keybinding cheatsheet and launcher: hydra in the case of ivy, and transient for magit. The current package key-assist offers a generic and very simple alternative requiring only the completing-read function commonly used in core vanilla Emacs. key-assist is trivial to implement "on-the-fly" interactively for any buffer, and programmatically much simpler to customize that either hydra or transient. And it only requires the Emacs core function completing-read.

What it look likes

How `key-assist' output displays will largely depend on what you use for your minibuffer completions. Here's an example of the default output for an *Occur* buffer.

Select an item on the list to launch it:
  e     Major mode for editing *Occur* buffers.
> o     occur-mode-goto-occurrence-other-window (not documented)
  r     Rename the current *Occur* buffer to *Occur: original-buffer-name*.
  C-o   occur-mode-display-occurrence (not documented)
  M-n   Move to the Nth (default 1) next match in an Occur mode buffer.
  M-p   Move to the Nth (default 1) previous match in an Occur mode buffer.
  RET   Go to the occurrence on the current line.
  M-s o Drop-in replacement for `occur', but when called with a prefix

Dependencies:

cl-lib: For cl-member,cl-position

Installation:

1. Evaluate or load this file.

Interactive operation:

Run M-x key-assist from the buffer of interest. Specify a selection (or don't), press to view the presentation, and then either exit with your new-found knowledge of the command keybindings, or use standard Emacs tab completion to select an option, and press to perform the action.

If you choose not to respond to the initial prompt, a list of keybindings and command descriptions will be generated based upon the first word of the buffer's major mode. For, example, in a w3m buffer, the list will be of all interactive functions beginning w3m-. This works out to be great as a default, but isn't always useful. For example, in an emacs-lisp-mode buffer or a lisp-interaction-mode, what would you expect it to usefully produce? At the other extreme might be a case of a buffer with too many obscure keybindings of little use.

You can also respond to the prompt with your own regexp of any set of commands to show, or with the name of a keymap of your choice. For the purposes of key-assist, a regexp can be just a substring, without REQUIRING any leading or trailing globs.

In all cases, note that the package can only present keybindings currently active in the current buffer, so if a sub-package hasn't been loaded yet, that package's keybindings would not be presented. Also note that the commands are presented sorted by keybinding length, alphabetically.

Programmating example:

Here's a most simple example that presents all of the keybindings for 'my-mode:

(defun my-mode-keybinding-cheatsheet-launcher ()
  (interactive)
  (when (eq major-mode my-mode)
    (key-assist)))
(define-key my-mode-map "?"
            'my-mode-keybinding-cheatsheet-launcher)

See the docstrings for functions key-assist and key-assist--get-cmds for the description of ARGS that can be used to customize the output.

Configuration:

Two variables are available to exclude items from the presentation list: key-assist-exclude-cmds and key-assist-exclude-regexps. See there for further information.

Compatability

Tested with Emacs 26.1 and emacs-snapshot 28(~2020-09-16), both in debian.

Colophon

• Copyright © 2020, Boruch Baum [email protected]
• Author/Maintainer: Boruch Baum [email protected]
• Homepage: https://github.com/Boruch-Baum/emacs-key-assist
• License: GPLv3+

Some other Emacs software by this author

• Diredc

  • Large collection of interoperable dired extensions
  • https://github.com/Boruch-Baum/emacs-diredc

• Emacs-w3m

  • Extensions to the classic web browser (fork)
    • Advanced downloader (bulk, regex, queue management, resume aborted)
    • Scrub history
    • More ...
  • https://github.com/Boruch-Baum/emacs-w3m

• Crossword

  • Download and play crossword puzzles, in Emacs!
  • https://github.com/Boruch-Baum/emacs-crossword

• Key-assist

  • Simple keybinding cheatsheet and launcher
  • https://github.com/Boruch-Baum/emacs-key-assist

• Home-end

  • Turn home and end keys to multi-use navigation keys
  • https://github.com/Boruch-Baum/emacs-home-end

• Keypress-multi-event

  • perform different actions when repeating a key
  • https://github.com/Boruch-Baum/emacs-keypress-multi-event

• Post-mode - Updates to the abandoned email editing package (fork)

  • https://github.com/Boruch-Baum/post-mode