Xah Talk Show 2025-09-07 Ep699 Emacs Lisp defvar-keymap, define-keymap , part 2

Video Summary

AI Generated (human edited)

This video focuses on updating Emacs Lisp code to use new, simpler key binding functions introduced in Emacs 29 (released two years ago).

Here's a summary:

• The speaker explains that Emacs 29 brought significant changes to how keyboard shortcuts (key bindings) are defined, making the code much simpler and shorter compared to older versions (0:57, 9:02).
• In Emacs, every keystroke invokes a command, and users can assign keyboard shortcuts to any command (3:30, 6:42).
• The main goal of the video is to refactor the speaker's personal Emacs Lisp packages from using the old define-key function to the new define-var-keymap and keymap-set functions (10:05, 10:11).
• The speaker demonstrates this refactoring process for several packages, highlighting the reduction in code complexity and explaining how to handle "leader keys" for customizable major mode commands (24:00, 26:15).
• A new syntax for the tab key, specifically kbd, is also introduced, which helps distinguish the tab key from the tab character, especially in terminal Emacs (30:37).
• Towards the end, the speaker answers viewer questions about Emacs key bindings, keyboard ergonomics, and using various keyboard layouts (41:00, 47:00).

• 4chan Emacs Xah

• define-keymap
• defvar-keymap

• Elisp: Create Keymap (keybinding)
• Emacs Keys
• Emacs Keys: Define Key
• Emacs Keys: Keybinding Functions, Emacs 29 Change

• Emacs: Xah Fly Keys 📦

• ASCII Characters

;; HHHH------------------------------
;; BEFORE

(defvar xah-python-mode-map nil "Keymap for `xah-python-mode-mode'")
(progn
  (setq xah-python-mode-map (make-sparse-keymap))
  (define-key xah-python-mode-map (kbd "TAB TAB") #'xah-python-indent)
  (define-key xah-python-mode-map (kbd "TAB SPC") #'xah-python-complete-symbol)
  (define-key xah-python-mode-map (kbd "TAB r") #'xah-python-eval-region)
  (define-key xah-python-mode-map (kbd "TAB l") #'xah-python-eval-current-line)
  (define-key xah-python-mode-map (kbd "TAB f") #'xah-python-format-buffer))

;; HHHH------------------------------
;; AFTER

(defvar-keymap xah-python-mode-map
  :doc "Keymap for `xah-python-mode-mode'"
  "<tab> <tab>" #'xah-python-indent
  "<tab> SPC" #'xah-python-complete-symbol
  "<tab> r" #'xah-python-eval-region
  "<tab> l" #'xah-python-eval-current-line
  "<tab> f" #'xah-python-format-buffer)