fuzzy-regexp: Fuzzy-matching regexp generator for Emacs

Copyright (C) 2014 Hisashi Morita

• Author: Hisashi Morita
• Keywords: convenience, matching, wp
• License: Public Domain
• URL: https://github.com/hisashim/fuzzyregexp

(fuzzy-regexp STR &optional WORD-MATCH SELF-INCLUSIVE)

Generate regexp to match strings that are modification of STR by one character.

• If WORD-MATCH is true, regexp tries to match whole words only (not substrings).
• If SELF-INCLUSIVE is true, regexp alsos matches STR itself.

Plain use without options.

(fuzzy-regexp "the")
;;=> "[^t]he\\|te\\|th[^e]\\|t.he\\|th.e\\|t[^h]e\\|hte\\|teh"
;;   Matches "teh", "thi", "this", etc.
;;   Does not match "the" itself.

Enable word-match option for word-oriented match. (This may not work as intended for languages such as Chinese or Japanese.)

(fuzzy-regexp "the" t nil)
;;=> "\\b\\(?:[^t]he\\|te\\|th[^e]\\|t.he\\|th.e\\|t[^h]e\\|hte\\|teh\\)\\b"
;;   Matches "teh", "thi", etc.
;;   Does not match substrings within words such as "thi" in "this".
;;   Does not match "the" itself.

Enable self-inclusive option to match the search keyword itself.

(fuzzy-regexp "the" nil t)
;;=> "the\\|[^t]he\\|te\\|th[^e]\\|t.he\\|th.e\\|t[^h]e\\|hte\\|teh"
;;   Matches "teh", "thi", "this", etc.
;;   Matches "the" itself.

If you want case-sensitive/insensitive search, set case-fold-search.

(let ((case-fold-search t))
  (search-forward-regexp (fuzzy-regexp "the")))
;;=> Matches "Teh", "teh", "Thi", "thi", "This", "this", etc.
;;   Does not match "The" or "the".

1. Copy fuzzy-regexp.el to somewhere in load-path.
2. Add (require 'fuzzy-regexp) to your init file, e.g. ~/.emacs.d/init.el.
3. Restart Emacs.

I needed a fuzzy matching library which can exclude query keyword itself from the result, in order to find typographical errors in natural language text, but could not find one. So I hacked up this kludge.

Fuzzy/ambiguous/approximate matching libraries and applications that I know of:

• Helm
• fuzzy.el
• approx-search

You may want to try these first.