master 746a3cb3143: Ignore parens in strings for outline headings in emacs-lisp-mode.

[Juri Linkov]

branch: master
commit 746a3cb3143194436c4a1a63d26aac890c1a705f
Author: Juri Linkov <juri@linkov.net>
Commit: Juri Linkov <juri@linkov.net>

    Ignore parens in strings for outline headings in emacs-lisp-mode.
    
    * lisp/outline.el (outline-font-lock-keywords): For non-nil
    outline-search-function return a lambda that calls the function,
    then sets the match data to the end of the line that is equivalent
    to adding ".*" in the regexp.  Then search functions don't need to
    match ".*" themselves.
    
    * lisp/progmodes/elisp-mode.el (elisp-outline-search):
    New function to skip leading parens in strings when searching
    for outline headings.
    (emacs-lisp-mode): Set buffer-local 'outline-search-function' to
    'elisp-outline-search'.
    https://lists.gnu.org/archive/html/emacs-devel/2025-04/msg00934.html
---
 lisp/outline.el              |  7 ++++++-
 lisp/progmodes/elisp-mode.el | 14 ++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/lisp/outline.el b/lisp/outline.el
index a53e0a1f070..e484bcef878 100644
--- a/lisp/outline.el
+++ b/lisp/outline.el
@@ -261,7 +261,12 @@ non-nil and point is located on the heading line.")
 (defvar outline-font-lock-keywords
   '(
     ;; Highlight headings according to the level.
-    (eval . (list (or outline-search-function
+    (eval . (list (or (when outline-search-function
+                        (lambda (limit)
+                          (when-let* ((ret (funcall outline-search-function 
limit)))
+                            ;; This is equivalent to adding ".*" in the regexp 
below.
+                            (set-match-data (list (match-beginning 0) 
(pos-eol)))
+                            ret)))
                       (concat "^\\(?:" outline-regexp "\\).*" 
outline-heading-end-regexp))
                   0 '(if outline-minor-mode
                          (if outline-minor-mode-highlight
diff --git a/lisp/progmodes/elisp-mode.el b/lisp/progmodes/elisp-mode.el
index e8b2a8da65e..a9c00085056 100644
--- a/lisp/progmodes/elisp-mode.el
+++ b/lisp/progmodes/elisp-mode.el
@@ -287,6 +287,19 @@ Comments in the form will be lost."
             (string-to-syntax "'")))))
      start end)))
 
+(defun elisp-outline-search (&optional bound move backward looking-at)
+  "Don't use leading parens in strings for outline headings."
+  (if looking-at
+      (and (looking-at outline-regexp)
+           (save-excursion (not (nth 8 (syntax-ppss (match-beginning 0))))))
+    (let ((search-success nil))
+      (while (and (setq search-success
+                        (funcall (if backward #'re-search-backward 
#'re-search-forward)
+                                 (concat "^\\(?:" outline-regexp "\\)")
+                                 bound (if move 'move t)))
+                  (save-excursion (nth 8 (syntax-ppss (match-beginning 0))))))
+      search-success)))
+
 (defcustom emacs-lisp-mode-hook nil
   "Hook run when entering Emacs Lisp mode."
   :options '(eldoc-mode imenu-add-menubar-index checkdoc-minor-mode)
@@ -382,6 +395,7 @@ be used instead.
   (add-hook 'xref-backend-functions #'elisp--xref-backend nil t)
   (setq-local project-vc-external-roots-function #'elisp-load-path-roots)
   (setq-local syntax-propertize-function #'elisp-mode-syntax-propertize)
+  (setq-local outline-search-function #'elisp-outline-search)
   (add-hook 'completion-at-point-functions
             #'elisp-completion-at-point nil 'local)
   (add-hook 'flymake-diagnostic-functions #'elisp-flymake-checkdoc nil t)