setting up a buffer-local value for the variable
@code{font-lock-defaults} (@pxref{Font Lock Mode}).
+@item
+Each face that the mode defines should, if possible, inherit from an
+existing Emacs face. This reduces the chance of conflicting with a
+user's face customizations. Useful faces include:
+
+@table @asis
+@item @code{highlight}
+for stretches of text that should temporarily stand out.
+
+@item @code{match}
+for text matching a search command.
+
+@item @code{link} and @code{link-visited}
+for clickable text buttons that send the user to a different buffer or
+``location''.
+
+@item @code{button}
+for clickable text buttons that perform other actions.
+
+@item @asis{Font Lock faces}
+for other kinds of syntactic highlighting, if highlighting is not
+handled by Font Lock mode or some Font Lock faces are not in use.
+@xref{Faces for Font Lock}, for how to assign Font Lock faces.
+@end table
+
@item
The mode should specify how Imenu should find the definitions or
sections of a buffer, by setting up a buffer-local value for the
@cindex faces for font lock
@cindex font lock faces
- You can make Font Lock mode use any face, but several faces are
-defined specifically for Font Lock mode. Each of these symbols is both
-a face name, and a variable whose default value is the symbol itself.
-Thus, the default value of @code{font-lock-comment-face} is
-@code{font-lock-comment-face}. This means you can write
-@code{font-lock-comment-face} in a context such as
-@code{font-lock-keywords} where a face-name-valued expression is used.
-
-@table @code
-@item font-lock-comment-face
-@vindex font-lock-comment-face
-Used (typically) for comments.
-
-@item font-lock-comment-delimiter-face
-@vindex font-lock-comment-delimiter-face
-Used (typically) for comments delimiters.
-
-@item font-lock-doc-face
-@vindex font-lock-doc-face
-Used (typically) for documentation strings in the code.
+ Font Lock mode can highlight using any face, but Emacs defines several
+faces specifically for syntactic highlighting. These @dfn{Font Lock
+faces} are listed below. They can also be used by major modes for
+syntactic highlighting outside of Font Lock mode (@pxref{Major Mode
+Conventions}).
-@item font-lock-string-face
-@vindex font-lock-string-face
-Used (typically) for string constants.
+ Each of these symbols is both a face name, and a variable whose
+default value is the symbol itself. Thus, the default value of
+@code{font-lock-comment-face} is @code{font-lock-comment-face}.
-@item font-lock-keyword-face
-@vindex font-lock-keyword-face
-Used (typically) for keywords---names that have special syntactic
-significance, like @code{for} and @code{if} in C.
+ The faces are listed with descriptions of their typical usage, and in
+order of greater to lesser ``prominence''. If a mode's syntactic
+categories do not fit well with the usage descriptions, the faces can be
+assigned using the ordering as a guide.
-@item font-lock-builtin-face
-@vindex font-lock-builtin-face
-Used (typically) for built-in function names.
+@table @code
+@item font-lock-warning-face
+@vindex font-lock-warning-face
+for a construct that is peculiar, or that greatly changes the meaning of
+other text, like @samp{;;;###autoload} in Emacs Lisp and @samp{#error}
+in C.
@item font-lock-function-name-face
@vindex font-lock-function-name-face
-Used (typically) for the name of a function being defined or declared,
-in a function definition or declaration.
+for the name of a function being defined or declared.
@item font-lock-variable-name-face
@vindex font-lock-variable-name-face
-Used (typically) for the name of a variable being defined or declared,
-in a variable definition or declaration.
+for the name of a variable being defined or declared.
+
+@item font-lock-keyword-face
+@vindex font-lock-keyword-face
+for a keyword with special syntactic significance, like @samp{for} and
+@samp{if} in C.
+
+@item font-lock-comment-face
+@vindex font-lock-comment-face
+for comments.
+
+@item font-lock-comment-delimiter-face
+@vindex font-lock-comment-delimiter-face
+for comments delimiters, like @samp{/*} and @samp{*/} in C. On most
+terminals, this inherits from @code{font-lock-comment-face}.
@item font-lock-type-face
@vindex font-lock-type-face
-Used (typically) for names of user-defined data types,
-where they are defined and where they are used.
+for the names of user-defined data types.
@item font-lock-constant-face
@vindex font-lock-constant-face
-Used (typically) for constant names.
+for the names of constants, like @samp{NULL} in C.
+
+@item font-lock-builtin-face
+@vindex font-lock-builtin-face
+for the names of built-in functions.
@item font-lock-preprocessor-face
@vindex font-lock-preprocessor-face
-Used (typically) for preprocessor commands.
+for preprocessor commands. This inherits, by default, from
+@code{font-lock-builtin-face}.
+
+@item font-lock-string-face
+@vindex font-lock-string-face
+for string constants.
+
+@item font-lock-doc-face
+@vindex font-lock-doc-face
+for documentation strings in the code. This inherits, by default, from
+@code{font-lock-string-face}.
@item font-lock-negation-char-face
@vindex font-lock-negation-char-face
-Used (typically) for easily-overlooked negation characters.
-
-@item font-lock-warning-face
-@vindex font-lock-warning-face
-Used (typically) for constructs that are peculiar, or that greatly
-change the meaning of other text. For example, this is used for
-@samp{;;;###autoload} cookies in Emacs Lisp, and for @code{#error}
-directives in C.
+for easily-overlooked negation characters.
@end table
@node Syntactic Font Lock
@menu
* Font Lock Multiline:: Marking multiline chunks with a text property.
-* Region to Fontify:: Controlling which region gets refontified
+* Region to Refontify:: Controlling which region gets refontified
after a buffer change.
@end menu
Font-Lock looks at it, or use
@code{font-lock-fontify-region-function}.
-@node Region to Fontify
+@node Region to Refontify
@subsubsection Region to Fontify after a Buffer Change
When a buffer is changed, the region that Font Lock refontifies is
example, when a change alters the syntactic meaning of text on an
earlier line.
- You can enlarge (or even reduce) the region to fontify by setting
-one the following variables:
+ You can enlarge (or even reduce) the region to refontify by setting
+the following variable:
@defvar font-lock-extend-after-change-region-function
This buffer-local variable is either @code{nil} or a function for
Font-Lock to call to determine the region to scan and fontify.
The function is given three parameters, the standard @var{beg},
-@var{end}, and @var{old-len} from after-change-functions
+@var{end}, and @var{old-len} from @code{after-change-functions}
(@pxref{Change Hooks}). It should return either a cons of the
beginning and end buffer positions (in that order) of the region to
fontify, or @code{nil} (which means choose the region in the standard
@end defvar
@node Auto-Indentation
-@section Auto-indention of code
+@section Auto-indentation of code
For programming languages, an important feature of a major mode is to
provide automatic indentation. This is controlled in Emacs by
or right-associativity of infix operators, nesting of tokens like
parentheses and many other cases.
-@c ยกLet's leave this undocumented to leave it more open for change!
+@c Let's leave this undocumented to leave it more open for change!
@c @defvar smie-grammar
@c The value of this variable is an alist specifying the left and right
@c precedence of each token. It is meant to be initialized by using one of
HCoop / bpt / emacs.git / blobdiff