* 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.
* Left Margin Paren:: An open-paren or similar opening delimiter
starts a defun if it is at the left margin.
* Moving by Defuns:: Commands to move over or mark a major definition.
+* Moving by Sentences:: Commands to move over certain code units.
* Imenu:: Making buffer indexes as menus.
* Which Function:: Which Function mode shows which function you are in.
@end menu
language. Other major modes may replace any or all of these key
bindings for that purpose.
+@node Moving by Sentences
+@subsection Moving by Sentences
+@cindex sentences, in programming languages
+
+ These commands move point or set up the region based on units of
+code, also called @dfn{sentences}. Even though sentences are usually
+considered when writing human languages, Emacs can use the same
+commands to move over certain constructs in programming languages
+(@pxref{Sentences}, @pxref{Moving by Defuns}). In a programming
+language a sentence is usually a complete language construct smaller
+than defuns, but larger than sexps (@pxref{List Motion,,, elisp, The
+Emacs Lisp Reference Manual}). What exactly a sentence is in a
+non-human language is dependent on the target language, but usually it
+is complete statements, such as a variable definition and
+initialization, or a conditional statement. An example of a sentence
+in the C language could be
+
+@example
+int x = 5;
+@end example
+
+or in the JavaScript language it could look like
+
+@example
+const thing = () => console.log("Hi");
+
+const foo = [1] == '1'
+ ? "No way"
+ : "...";
+@end example
+
+@table @kbd
+@item M-a
+Move to beginning of current or preceding sentence
+(@code{backward-sentence}).
+@item M-e
+Move to end of current or following sentence (@code{forward-sentence}).
+@end table
+
+@cindex move to beginning or end of sentence
+@cindex sentence, move to beginning or end
+@kindex M-a @r{(programming modes)}
+@kindex M-e @r{(programming modes)}
+@findex backward-sentence @r{(programming modes)}
+@findex forward-sentence @r{(programming modes)}
+ The commands to move to the beginning and end of the current
+sentence are @kbd{M-a} (@code{backward-sentence}) and @kbd{M-e}
+(@code{forward-sentence}). If you repeat one of these commands, or
+use a positive numeric argument, each repetition moves to the next
+sentence in the direction of motion.
+
+ @kbd{M-a} with a negative argument @minus{}@var{n} moves forward
+@var{n} times to the next end of a sentence. Likewise, @kbd{M-e} with
+a negative argument moves back to a start of a sentence.
+
@node Imenu
@subsection Imenu
@cindex index of buffer definitions
of a sentence. Set the variable @code{sentence-end-without-period} to
@code{t} in such cases.
+ Even though the above mentioned sentence movement commands are based
+on human languages, other Emacs modes can set these command to get
+similar functionality (@pxref{Moving by Sentences}).
+
@node Paragraphs
@section Paragraphs
@cindex paragraphs
recognize nested defuns.
@end defvar
+@defvar treesit-sentence-type-regexp
+The value of this variable is a regexp matching the node type of sentence
+nodes. (For ``node'' and ``node type'', @pxref{Parsing Program Source}.)
+@end defvar
+
+@findex treesit-forward-sentence
+@findex forward-sentence
+@findex backward-sentence
+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 sentence varies between languages, a major
+mode should set @code{treesit-sentence-type-regexp} to determine that.
+Then the mode can get navigation-by-sentence functionality for free,
+by using @code{forward-sentence} and
+@code{backward-sentence}(@pxref{Moving by Sentences,,, emacs, The
+extensible self-documenting text editor}).
+
@node Skipping Characters
@subsection Skipping Characters
@cindex skipping characters
Tree-sitter modes. This functionality utilizes the new
'transpose-sexps-function'.
+** Commands and variables to move by program statements
+
+*** New variable 'forward-sentence-function'.
+Major modes now can set this variable to customize the behavior of the
+'forward-sentence' function.
+
+*** New function 'forward-sentence-default-function'.
+The previous implementation of 'forward-sentence' is moved into its
+own function, to be bound by 'forward-sentence-function'.
+
+*** New defvar-local 'treesit-sentence-type-regexp.
+Similarly to 'treesit-defun-type-regexp', this variable is used to
+navigate sentences in Tree-sitter enabled modes.
+
+*** New function 'treesit-forward-sentence'.
+treesit.el now conditionally sets 'forward-sentence-function' for all
+Tree-sitter modes that sets 'treesit-sentence-type-regexp'.
+
\f
* Changes in Specialized Modes and Packages in Emacs 30.1
---
(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)))
(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)
\"text_block\" in the case of a string. This is used by
`prog-fill-reindent-defun' and friends.")
+(defvar-local treesit-sentence-type-regexp nil
+ "A regexp that matches the node type of sentence nodes.
+
+A sentence node is a node that is bigger than a sexp, and
+delimits larger statements in the source code. It is, however,
+smaller in scope than defuns. This is used by
+`treesit-forward-sentence' and friends.")
+
+(defun treesit-forward-sentence (&optional arg)
+ "Tree-sitter `forward-sentence-function' function.
+
+ARG is the same as in `forward-sentence'.
+
+If inside comment or other nodes described in
+`treesit-sentence-type-regexp', use
+`forward-sentence-default-function', else move across nodes as
+described by `treesit-sentence-type-regexp'."
+ (if (string-match-p
+ treesit-text-type-regexp
+ (treesit-node-type (treesit-node-at (point))))
+ (funcall #'forward-sentence-default-function arg)
+ (funcall
+ (if (> arg 0) #'treesit-end-of-thing #'treesit-beginning-of-thing)
+ treesit-sentence-type-regexp (abs arg))))
+
(defun treesit-default-defun-skipper ()
"Skips spaces after navigating a defun.
This function tries to move to the beginning of a line, either by
#'treesit-add-log-current-defun))
(setq-local transpose-sexps-function #'treesit-transpose-sexps)
+ (when treesit-sentence-type-regexp
+ (setq-local forward-sentence-function #'treesit-forward-sentence))
;; Imenu.
(when treesit-simple-imenu-settings