Add treesit-forward-sexp (bug#60894)

* lisp/progmodes/java-ts-mode.el (java-ts-mode): Use
treesit-sexp-type-regexp.
* lisp/treesit.el (treesit-sexp-type-regexp): New defvar.
(treesit-forward-sexp): New command.
(treesit-major-mode-setup): Conditionally set forward-sexp-function.
* lisp/progmodes/ruby-ts-mode.el: Add some types to ruby-ts-mode.
* doc/lispref/positions.texi (List Motion): Mention the change in the
manual.
* etc/NEWS: Mention the change.

doc/lispref/positions.texi

@@ -875,6 +875,23 @@ by using @code{forward-sentence} and
 @code{backward-sentence}(@pxref{Moving by Sentences,,, emacs, The
 extensible self-documenting text editor}).
 
+@defvar treesit-sexp-type-regexp
+The value of this variable is a regexp matching the node type of sexp
+nodes.  (For ``node'' and ``node type'', @pxref{Parsing Program
+Source}.)
+@end defvar
+
+@findex treesit-forward-sexp
+@findex forward-sexp@r{, and tree-sitter}
+@findex backward-sexp@r{, and tree-sitter}
+If Emacs is compiled with tree-sitter, it can use the tree-sitter
+parser information to move across syntax constructs.  Since what
+exactly is considered a sexp varies between languages, a major mode
+should set @code{treesit-sexp-type-regexp} to determine that.  Then
+the mode can get navigation-by-sexp functionality for free, by using
+@code{forward-sexp} and @code{backward-sexp}(@pxref{Moving by
+Sentences,,, emacs, The extensible self-documenting text editor}).
+
 @node Skipping Characters
 @subsection Skipping Characters
 @cindex skipping characters

etc/NEWS

@@ -84,6 +84,15 @@ define "sentences" in Tree-sitter enabled modes.
 All tree-sitter modes that define 'treesit-sentence-type-regexp' now
 set 'forward-sentence-function' to call 'treesit-forward-sentence'.
 
+*** New defvar-local 'treesit-sexp-type-regexp'.
+Similarly to 'treesit-defun-type-regexp', this variable is used to
+define "sexps" in Tree-sitter enabled modes.
+
+*** New function 'treesit-forward-sexp'.
+treesit.el conditionally sets 'forward-sexp-function` for major modes
+that have defined 'treesit-sexp-type-regexp' to enable sexp-related
+motion commands.
+
 
 * Changes in Specialized Modes and Packages in Emacs 30.1
 ---

lisp/progmodes/java-ts-mode.el

@@ -328,6 +328,21 @@ Return nil if there is no name or if NODE is not a defun node."
                             "package_declaration"
                             "import_declaration")))
 
+  (setq-local treesit-sexp-type-regexp
+              (regexp-opt '("annotation"
+                            "parenthesized_expression"
+                            "argument_list"
+                            "identifier"
+                            "modifiers"
+                            "block"
+                            "body"
+                            "literal"
+                            "access"
+                            "reference"
+                            "_type"
+                            "true"
+                            "false")))
+
   ;; Font-lock.
   (setq-local treesit-font-lock-settings java-ts-mode--font-lock-settings)
   (setq-local treesit-font-lock-feature-list

lisp/progmodes/ruby-ts-mode.el

@@ -1008,6 +1008,20 @@ leading double colon is not added."
   ;; Navigation.
   (setq-local treesit-defun-type-regexp ruby-ts--method-regex)
 
+  (setq-local treesit-sexp-type-regexp
+              (regexp-opt '("class"
+                            "module"
+                            "method"
+                            "argument_list"
+                            "array"
+                            "hash"
+                            "parenthesized_statements"
+                            "if"
+                            "case"
+                            "block"
+                            "do_block"
+                            "begin")))
+
   ;; AFAIK, Ruby can not nest methods
   (setq-local treesit-defun-prefer-top-level nil)
 

lisp/treesit.el

@@ -1636,6 +1636,21 @@ BACKWARD and ALL are the same as in `treesit-search-forward'."
       (goto-char current-pos)))
     node))
 
+(defvar-local treesit-sexp-type-regexp nil
+  "A regexp that matches the node type of sexp nodes.
+
+A sexp node is a node that is bigger than punctuation, and
+delimits medium sized statements in the source code.  It is,
+however, smaller in scope than sentences.  This is used by
+`treesit-forward-sexp' and friends.")
+
+(defun treesit-forward-sexp (&optional arg)
+  (interactive "^p")
+  (or arg (setq arg 1))
+  (funcall
+   (if (> arg 0) #'treesit-end-of-thing #'treesit-beginning-of-thing)
+   treesit-sexp-type-regexp (abs arg)))
+
 (defun treesit-transpose-sexps (&optional arg)
   "Tree-sitter `transpose-sexps' function.
 Arg is the same as in `transpose-sexps'.
@@ -2301,6 +2316,8 @@ before calling this function."
     (setq-local add-log-current-defun-function
                 #'treesit-add-log-current-defun))
 
+  (when treesit-sexp-type-regexp
+    (setq-local forward-sexp-function #'treesit-forward-sexp))
   (setq-local transpose-sexps-function #'treesit-transpose-sexps)
   (when treesit-sentence-type-regexp
     (setq-local forward-sentence-function #'treesit-forward-sentence))