Add forward-sentence with tree sitter support (bug#60623)

* etc/NEWS: Mention the new changes.
* lisp/textmodes/paragraphs.el (forward-sentence-default-function):
Move old implementation to its own function.
(forward-sentence-function): New defvar defaulting to old behavior.
(forward-sentence): Use the variable in this function unconditionally.
* lisp/treesit.el (treesit-sentence-type-regexp): New defvar.
(treesit-forward-sentence): New defun.
(treesit-major-mode-setup): Conditionally set
forward-sentence-function.
* doc/emacs/programs.texi (Defuns): Add new subsection.
(Moving by Sentences): Add some documentation with xrefs to the elisp
manual and related nodes.
* doc/lispref/positions.texi (List Motion): Mention
treesit-sentence-type-regexp and describe how to enable this
functionality.

1 files changed, 13 insertions, 2 deletions

diff --git a/lisp/textmodes/paragraphs.el b/lisp/textmodes/paragraphs.el
index 73abb155aaa..bf249fdcdfb 100644
--- a/lisp/textmodes/paragraphs.el
+++ b/lisp/textmodes/paragraphs.el
@@ -441,13 +441,12 @@ the current paragraph with the one containing the mark."
 	  (if (< (point) (point-max))
 	      (end-of-paragraph-text))))))
 
-(defun forward-sentence (&optional arg)
+(defun forward-sentence-default-function (&optional arg)
   "Move forward to next end of sentence.  With argument, repeat.
 When ARG is negative, move backward repeatedly to start of sentence.
 
 The variable `sentence-end' is a regular expression that matches ends of
 sentences.  Also, every paragraph boundary terminates sentences as well."
-  (interactive "^p")
   (or arg (setq arg 1))
   (let ((opoint (point))
         (sentence-end (sentence-end)))
@@ -480,6 +479,18 @@ sentences.  Also, every paragraph boundary terminates sentences as well."
     (let ((npoint (constrain-to-field nil opoint t)))
       (not (= npoint opoint)))))
 
+(defvar forward-sentence-function #'forward-sentence-default-function
+  "Function to be used to calculate sentence movements.
+See `forward-sentence' for a description of its behavior.")
+
+(defun forward-sentence (&optional arg)
+  "Move forward to next end of sentence.  With argument ARG, repeat.
+If ARG is negative, move backward repeatedly to start of
+sentence.  Delegates its work to `forward-sentence-function'."
+  (interactive "^p")
+  (or arg (setq arg 1))
+  (funcall forward-sentence-function arg))
+
 (defun count-sentences (start end)
   "Count sentences in current buffer from START to END."
   (let ((sentences 0)