The greedy regexp matching, broken scoring and broken highlight were
sources of frequent complaints about the 'flex' matching style. This
commit fixes that.
Inspired by the 'hotfuzz' style (available at
https://github.com/axelf4/hotfuzz) it uses a modified version of Gotoh's
1982 dynamic programming algorithm. It is strictly more correct than the
"old" flex. For example, when matching the pattern 'goto' to no longer
will 'eglot-format' be sorted before some hypothetical much better
'goobarbaz-goto'. And of course the highlighting is also correctly
placed on the 'goto', not scattered across the candidate.
Regarding performance, it is faster than the naive 'flex', primarily
because of the Elisp rewrite in minibuffer.el. The matching and costing
algorithm matters but is not the bottleneck.
The Elisp parts of the style were almost completely decoupled from the
pcm/substring styles in lisp/minibuffer.el. Only
'completion-flex-try-completion' uses some of pcm's code for pattern
augmentation.
* src/minibuf.c (completion--flex-cost-gotoh): New function.
* lisp/minibuffer.el (completion-flex--pattern-str): New variable.
(flex-score-match-tightness): Make obsolete.
(completion--flex-all-completions-1): New helper function.
(completion-flex-try-completion, completion-flex-all-completions): Rewrite.
(completion-substring--all-completions): No longer take transform-pattern-fn.
(completion--flex-adjust-metadata): Tweak.
(completion--flex-score, completion--flex-score-1)
(completion--flex-score-last-md, completion-flex--make-flex-pattern): Delete.
* test/lisp/minibuffer-tests.el (completion--sorted-flex-completions):
New helper function.
(completion-flex-test-non-ascii): New test.
(completion--pcm-score): Delete.
(completion-pcm-test-3, completion-pcm-test-4)
(completion-substring-test-1, completion-substring-test-2)
(completion-flex-test-2, completion-flex-test-3): Tweak.
* etc/NEWS: Describe change.
This directory contains the architecture-independent files used by or
with Emacs. This includes some text files of documentation for GNU
Emacs or of interest to Emacs users, and the file of dumped docstrings
for Emacs functions and variables.
COPYRIGHT AND LICENSE INFORMATION FOR IMAGE FILES
File: emacs.icon
Author: Sun Microsystems, Inc
Copyright (C) 1999, 2001-2026 Free Software Foundation, Inc.
License: GNU General Public License version 3 or later (see COPYING)
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