use that customization buffer to customize the appearance of these
faces. @xref{Face Customization}.
+@cindex just-in-time (JIT) font-lock
+@cindex background syntax highlighting
+ Fontifying very large buffers can take a long time. To avoid large
+delays when a file is visited, Emacs initially fontifies only the
+visible portion of a buffer. As you scroll through the buffer, each
+portion that becomes visible is fontified as soon as it is displayed;
+this type of Font Lock is called @dfn{Just-In-Time} (or @dfn{JIT})
+Lock. You can control how JIT Lock behaves, including telling it to
+perform fontification while idle, by customizing variables in the
+customization group @samp{jit-lock}. @xref{Specific Customization}.
+
+ The information that major modes use for determining which parts of
+buffer text to fontify and what faces to use can be based on several
+different ways of analyzing the text:
+
+@itemize @bullet
+@item
+Search for keywords and other textual patterns based on regular
+expressions (@pxref{Regexp Search,, Regular Expression Search}).
+
+@item
+Find syntactically distinct parts of text based on built-in syntax
+tables (@pxref{Syntax Tables,,, elisp, The Emacs Lisp Reference
+Manual}).
+
+@item
+Use syntax tree produced by a full-blown parser, via a special-purpose
+library, such as the tree-sitter library (@pxref{Parsing Program
+Source,,, elisp, The Emacs Lisp Reference Manual}), or an external
+program.
+@end itemize
+
+@menu
+* Traditional Font Lock:: Font Lock based on regexps and syntax tables.
+* Parser-based Font Lock:: Font Lock based on external parser.
+@end menu
+
+@node Traditional Font Lock
+@subsection Traditional Font Lock
+@cindex traditional font-lock
+
+ ``Traditional'' methods of providing font-lock information are based
+on regular-expression search and on syntactic analysis using syntax
+tables built into Emacs. This subsection describes the use and
+customization of font-lock for major modes which use these traditional
+methods.
+
@vindex font-lock-maximum-decoration
- You can customize the variable @code{font-lock-maximum-decoration}
-to alter the amount of fontification applied by Font Lock mode, for
-major modes that support this feature. The value should be a number
-(with 1 representing a minimal amount of fontification; some modes
-support levels as high as 3); or @code{t}, meaning ``as high as
-possible'' (the default). To be effective for a given file buffer,
-the customization of @code{font-lock-maximum-decoration} should be
-done @emph{before} the file is visited; if you already have the file
-visited in a buffer when you customize this variable, kill the buffer
-and visit the file again after the customization.
+ You can control the amount of fontification applied by Font Lock
+mode by customizing the variable @code{font-lock-maximum-decoration},
+for major modes that support this feature. The value of this variable
+should be a number (with 1 representing a minimal amount of
+fontification; some modes support levels as high as 3); or @code{t},
+meaning ``as high as possible'' (the default). To be effective for a
+given file buffer, the customization of
+@code{font-lock-maximum-decoration} should be done @emph{before} the
+file is visited; if you already have the file visited in a buffer when
+you customize this variable, kill the buffer and visit the file again
+after the customization.
You can also specify different numbers for particular major modes; for
example, to use level 1 for C/C++ modes, and the default level
@pxref{Customizing Keywords,,, elisp, The Emacs Lisp Reference
Manual}.
-@cindex just-in-time (JIT) font-lock
-@cindex background syntax highlighting
- Fontifying large buffers can take a long time. To avoid large
-delays when a file is visited, Emacs initially fontifies only the
-visible portion of a buffer. As you scroll through the buffer, each
-portion that becomes visible is fontified as soon as it is displayed;
-this type of Font Lock is called @dfn{Just-In-Time} (or @dfn{JIT})
-Lock. You can control how JIT Lock behaves, including telling it to
-perform fontification while idle, by customizing variables in the
-customization group @samp{jit-lock}. @xref{Specific Customization}.
+@node Parser-based Font Lock
+@subsection Parser-based Font Lock
+@cindex font-lock via tree-sitter
+@cindex parser-based font-lock
+ If your Emacs was built with the tree-sitter library, it can use the
+results of parsing the buffer text by that library for the purposes of
+fontification. This is usually faster and more accurate than the
+``traditional'' methods described in the previous subsection, since
+the tree-sitter library provides full-blown parsers for programming
+languages and other kinds of formatted text which it supports. Major
+modes which utilize the tree-sitter library are named
+@code{@var{foo}-ts-mode}, with the @samp{-ts-} part indicating the use
+of the library. This subsection documents the Font Lock support based
+on the tree-sitter library.
+
+@vindex treesit-font-lock-level
+ You can control the amount of fontification applied by Font Lock
+mode of major modes based on tree-sitter by customizing the variable
+@code{treesit-font-lock-level}. Its value is a number between 1 and
+4:
+
+@table @asis
+@item Level 1
+This level usually fontifies only comments and function names in
+function definitions.
+@item Level 2
+This level adds fontification of keywords, strings, and data types.
+@item Level 3
+This is the default level; it adds fontification of assignments,
+numbers, properties, etc.
+@item Level 4
+This level adds everything else that can be fontified: operators,
+delimiters, brackets, other punctuation, function names in function
+calls, variables, etc.
+@end table
+
+@vindex treesit-font-lock-feature-list
+@noindent
+What exactly constitutes each of the syntactical categories mentioned
+above depends on the major mode and the parser grammar used by
+tree-sitter for the major-mode's language. However, in general the
+categories follow the conventions of the programming language or the
+file format supported by the major mode. The buffer-local value of
+the variable @code{treesit-font-lock-feature-list} holds the
+fontification features supported by a tree-sitter based major mode,
+where each sub-list shows the features provided by the corresponding
+fontification level.
+
+ Once you change the value of @code{treesit-font-lock-level} via
+@w{@kbd{M-x customize-variable}} (@pxref{Specific Customization}), it
+takes effect immediately in all the existing buffers and for files you
+visit in the future in the same session.
+
@node Highlight Interactively
@section Interactive Highlighting
language. Other major modes may replace any or all of these key
bindings for that purpose.
+@cindex nested defuns
+@vindex treesit-defun-tactic
+ Some programming languages supported @dfn{nested defuns}, whereby a
+defun (such as a function or a method or a class) can be defined
+inside (i.e., as part of the body) of another defun. The commands
+described above by default find the beginning and the end of the
+@emph{innermost} defun around point. Major modes based on the
+tree-sitter library provide control of this behavior: if the variable
+@code{treesit-defun-tactic} is set to the value @code{top-level}, the
+defun commands will find the @emph{outermost} defuns instead.
+
@node Imenu
@subsection Imenu
@cindex index of buffer definitions
@item C-c C-q
@kindex C-c C-q @r{(C mode)}
@findex c-indent-defun
+@findex c-ts-mode-indent-defun
Reindent the current top-level function definition or aggregate type
-declaration (@code{c-indent-defun}).
+declaration (@code{c-indent-defun} in CC mode,
+@code{c-ts-mode-indent-defun} in @code{c-ts-mode} based on tree-sitter).
@item C-M-q
@kindex C-M-q @r{(C mode)}
@findex c-indent-exp
-Reindent each line in the balanced expression that follows point
-(@code{c-indent-exp}). A prefix argument inhibits warning messages
-about invalid syntax.
+@findex prog-indent-sexp
+Reindent each line in the balanced expression that follows point. In
+CC mode, this invokes @code{c-indent-exp}; in tree-sitter based
+@code{c-ts-mode} this invokes a more general @code{prog-indent-sexp}.
+A prefix argument inhibits warning messages about invalid syntax.
@item @key{TAB}
@findex c-indent-line-or-region
@table @kbd
@item C-c . @var{style} @key{RET}
-Select a predefined style @var{style} (@code{c-set-style}).
+Select a predefined style @var{style} (@code{c-set-style} in CC mode,
+@code{c-ts-mode-set-style} in @code{c-ts-mode} based on tree-sitter).
@end table
A @dfn{style} is a named collection of customizations that can be
@kindex C-c . @r{(C mode)}
@findex c-set-style
+@findex c-ts-mode-set-style
To choose a style for the current buffer, use the command @w{@kbd{C-c
.}}. Specify a style name as an argument (case is not significant).
This command affects the current buffer only, and it affects only
new style, you can type @kbd{C-x h C-M-\}.
@vindex c-default-style
- You can also set the variable @code{c-default-style} to specify the
-default style for various major modes. Its value should be either the
-style's name (a string) or an alist, in which each element specifies
-one major mode and which indentation style to use for it. For
-example,
+ When using CC mode, you can also set the variable
+@code{c-default-style} to specify the default style for various major
+modes. Its value should be either the style's name (a string) or an
+alist, in which each element specifies one major mode and which
+indentation style to use for it. For example,
@example
(setq c-default-style
style for Java mode, you can make it take effect in an existing Java
mode buffer by typing @kbd{M-x java-mode} there.
+@vindex c-ts-mode-indent-style
+ When using the tree-sitter based @code{c-ts-mode}, you can set the
+default indentation style by customizing the variable
+@code{c-ts-mode-indent-style}.
+
The @code{gnu} style specifies the formatting recommended by the GNU
Project for C; it is the default, so as to encourage use of our
recommended style.
fontifications.
Level 1 usually contains only comments and definitions.
-Level 2 usually adds keywords, strings, constants, types, etc.
-Level 3 usually represents a full-blown fontification, including
-assignment, constants, numbers, properties, etc.
+Level 2 usually adds keywords, strings, data types, etc.
+Level 3 usually represents full-blown fontifications, including
+assignments, constants, numbers and literals, properties, etc.
Level 4 adds everything else that can be fontified: delimiters,
-operators, brackets, all functions and variables, etc.
+operators, brackets, punctuation, all functions and variables, etc.
In addition to the decoration level, individual features can be
turned on/off by calling `treesit-font-lock-recompute-features'.
Changing the decoration level requires calling
-`treesit-font-lock-recompute-features' to have an effect."
+`treesit-font-lock-recompute-features' to have an effect, unless
+done via `customize-variable'.
+
+To see which syntactical categories are fontified by each level
+in a particular major mode, examine the buffer-local value of the
+variable `treesit-font-lock-feature-list'."
:type 'integer
:set #'treesit--font-lock-level-setter
:version "29.1")
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