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Getting abbrev-mode to Expand Symbols in Emacs

1 min read

Enable abbrev-mode in Emacs to expand symbols like -> to → in Emacs, with a fix for symbol characters and Doom Emacs setup included.

# config
# doom emacs
# emacs
Not in series

I tried using abbrev-mode in Emacs to automatically expand things like -- into — and -> into →. I defined the abbreviations and enabled abbrev-mode, but nothing happened.

The issue is that symbol characters like -, <, and = aren’t considered part of words by default, so Emacs doesn’t recognize them as valid abbreviation triggers.

The Fix

To get around this, you can make those symbols word constituents using modify-syntax-entry:

(defun my/make-symbols-word-constituents ()
  "Allow symbols to be recognized in abbrev triggers."
  (modify-syntax-entry ?- "w")
  (modify-syntax-entry ?> "w"))

Then define your abbreviations:

(define-abbrev-table 'global-abbrev-table
  '(("--" "—")
    ("->" "→")))

Enable it in your desired mode(s):

(add-hook 'text-mode-hook #'abbrev-mode)
(add-hook 'text-mode-hook #'my/make-symbols-word-constituents)

Now, typing -> followed by a space will expand to →, -- to —, just like you’d expect.

Doom Emacs Users

If you’re using Doom Emacs, use after! and add-hook! like this:

(after! markdown-mode
  (add-hook! 'markdown-mode-hook 'abbrev-mode)
  (add-hook! 'markdown-mode-hook 'my/make-symbols-word-constituents))
 
(after! org
  (add-hook! 'org-mode-hook 'abbrev-mode)
  (add-hook! 'org-mode-hook 'my/make-symbols-word-constituents))

You can see my full configuration in cowboy-bebug/dotfiles@1121f2f. It includes the symbol setup, abbrev definitions, and mode hooks exactly as described above.