You can use @code{font-lock-add-keywords} to add additional
search-based fontification rules to a major mode, and
-@code{font-lock-remove-keywords} to remove rules. You can also set
-the @code{font-lock-ignore} variable to disable keywords that match
-certain criteria.
+@code{font-lock-remove-keywords} to remove rules. You can also
+customize the @code{font-lock-ignore} option to selectively disable
+fontification rules for keywords that match certain criteria.
@defun font-lock-add-keywords mode keywords &optional how
This function adds highlighting @var{keywords}, for the current buffer
font-lock-keyword-face)))))
@end smallexample
-@defvar font-lock-ignore
-This variable contains rules to selectively disable Font Lock
-keywords. It is a list with elements of the following form:
+@defopt font-lock-ignore
+@cindex selectively disabling font-lock fontifications
+This option defines conditions for selectively disabling
+fontifications due to certain Font Lock keywords. If non-@code{nil},
+its value is a list of elements of the following form:
@example
-(@var{mode} @var{rule} @dots{})
+(@var{symbol} @var{condition} @dots{})
@end example
-Here, @var{mode} is a symbol, say a major or minor mode. The
-subsequent rules apply if the current major mode is derived from
-@var{mode} or @var{mode} is bound and true as a variable. Each
-@var{rule} can be one of the following:
-
-@table @code
-@cindex @var{font-lock-ignore} rules
-@item @var{symbol}
-A symbol, say a face name, matches any Font Lock keyword containing
-the symbol in its definition. The symbol is interpreted as a glob
-pattern; in particular, @code{*} matches everything.
-
-@item @var{string}
-A string matches any font-lock keyword defined by a regexp that
-matches the string.
-
-@item (pred @var{function})
-A rule of this form matches if @var{function}, called with the
-Font Lock keyword as argument, returns non-@code{nil}.
-
-@item (not @var{rule})
-A rule of this form matches if @var{rule} doesn’t.
-
-@item (and @var{rule} @dots{})
-A rule of this form matches if each @var{rule} matches.
-
-@item (or @var{rule} @dots{})
-A rule of this form matches if some @var{rule} matches.
-
-@item (except @var{rule})
-A rule of this form can only be used at top level or inside an
-@code{or} clause. It undoes the effect of a previously matching rule.
+Here, @var{symbol} is a symbol, usually a major or minor mode. The
+subsequent @var{condition}s of a @var{symbol}'s list element will be in
+effect if @var{symbol} is bound and its value is non-@code{nil}. For
+a mode's symbol, it means that the current major mode is derived from
+that mode, or that minor mode is enabled in the buffer. When a
+@var{condition} is in effect, any fontifications caused by
+@code{font-lock-keywords} elements that match the @var{condition} will
+be disabled.
+
+Each @var{condition} can be one of the following:
+
+@table @asis
+@item a symbol
+This condition matches any element of Font Lock keywords that
+references the symbol. This is usually a face, but can be any symbol
+referenced by an element of the @code{font-lock-keywords} list. The
+symbol can contain wildcards: @code{*} matches any string in the
+symbol'ss name, @code{?} matches a single character, and
+@code{[@var{char-set}]}, where @var{char-set} is a string of one or
+more characters, matches a single character from the set.
+
+@item a string
+This condition matches any element of Font Lock keywords whose
+@var{matcher} is a regexp which matches the string. In other words,
+this condition matches a Font Lock rule which highlights the string.
+Thus, the string could be a specific program keyword whose
+highlighting you want to disable.
+
+@item @code{(pred @var{function})}
+This condition matches any element of Font Lock keywords for which
+@var{function}, when called with the element as the argument, returns
+non-@code{nil}.
+
+@item @code{(not @var{condition})}
+This matches if @var{condition} doesn’t.
+
+@item @code{(and @var{condition} @dots{})}
+This matches if each of the @var{condition}s matches.
+
+@item @code{(or @var{condition} @dots{})}
+This matches if at least one of the @var{condition}s matches.
+
+@item @code{(except @var{condition})}
+This condition can only be used at top level or inside an
+@code{or} clause. It undoes the effect of a previously matching
+condition on the same level.
@end table
-
-In each buffer, Font Lock keywords that match at least one applicable
-rule are disabled.
-@end defvar
+@end defopt
As an example, consider the following setting:
@enumerate
@item
-In all programming modes, disable all font-lock keywords that apply
-one of the standard font-lock faces (excluding strings and comments,
-which are covered by syntactic Font Lock).
+In all programming modes, disable fontifications due to all font-lock
+keywords that apply one of the standard font-lock faces (excluding
+strings and comments, which are covered by syntactic Font Lock).
@item
However, keep any keywords that add a @code{help-echo} text property.
@item
In Emacs Lisp mode, also keep the highlighting of autoload cookies,
-which would have been excluded by rule 1.
+which would have been excluded by the first condition.
@item
-In @code{whitespace-mode} (a minor mode), don't highlight an empty
-line at beginning of buffer.
+When @code{whitespace-mode} (a minor mode) is enabled, also don't
+highlight an empty line at beginning of buffer.
@item
-Finally, in Makefile mode, don't apply any ignore rules.
+Finally, in Makefile mode, don't apply any conditions.
@end enumerate
@node Other Font Lock Variables
:group 'font-lock)
(defcustom font-lock-ignore nil
- "Rules to selectively disable font-lock keywords.
-This is a list of rule sets of the form
+ "Rules to selectively disable fontifications due to `font-lock-keywords'.
+If non-nil, the value should be a list of condition sets of the form
- (MODE RULE ...)
+ (SYMBOL CONDITION ...)
where:
- - MODE is a symbol, say a major or minor mode. The subsequent
- rules apply if the current major mode is derived from MODE or
- MODE is bound and true as a variable.
+ - SYMBOL is a symbol, usually a major or minor mode. The subsequent
+ CONDITIONs apply if SYMBOL is bound as variable and its value is non-nil.
+ If SYMBOL is a symbol of a mode, that means the buffer has that mode
+ enabled (for major modes, it means the buffer's major mode is derived
+ from SYMBOL's mode).
- - Each RULE can be one of the following:
- - A symbol, say a face name. It matches any font-lock keyword
- containing the symbol in its definition. The symbol is
+ - Each CONDITION can be one of the following:
+ - A symbol, typically a face. It matches any element of
+ `font-lock-keywords' that references the symbol. The symbol is
interpreted as a glob pattern; in particular, `*' matches
- everything.
- - A string. It matches any font-lock keyword defined by a regexp
- that matches the string.
- - A form (pred FUNCTION). It matches if FUNCTION, which is called
- with the font-lock keyword as argument, returns non-nil.
- - A form (not RULE). It matches if RULE doesn't.
- - A form (and RULE ...). It matches if all the provided rules
- match.
- - A form (or RULE ...). It matches if any of the provided rules
- match.
- - A form (except RULE ...). This can be used only at top level or
- inside an `or' clause. It undoes the effect of a previous
- matching rule.
-
-In each buffer, font lock keywords that match at least one
-applicable rule are disabled."
+ everything, `?' matches any single character, and `[abcd]'
+ matches one character from the set.
+ - A string. It matches any element of `font-lock-keywords' whose
+ MATCHER is a regexp that matches the string. This can be used to
+ disable fontification of a particular programming keyword.
+ - A form (pred FUNCTION). It matches an element of `font-lock-keywords'
+ if FUNCTION, when called with the element as the argument, returns
+ non-nil.
+ - A form (not CONDITION). It matches if CONDITION doesn't.
+ - A form (and CONDITION ...). It matches if all the provided
+ CONDITIONs match.
+ - A form (or CONDITION ...). It matches if at least one of the
+ provided CONDITIONs matches.
+ - A form (except CONDITIONs ...). This can be used only at top level
+ or inside an `or' clause. It undoes the effect of previous
+ matching CONDITIONs on the same level.
+
+In each buffer, fontifications due to the elements of `font-lock-keywords'
+that match at least one applicable CONDITION are disabled."
:type '(alist :key-type symbol :value-type sexp)
:group 'font-lock
:version "29.1")
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