Handle "noise" macros and compiler directives.

* lisp/progmodes/cc-langs.el (c-symbol-char-key): New language variable.

* lisp/progmodes/cc-vars.el (c-noise-macro-names)
(c-noise-macro-with-parens-names): New customizable variables.
(c-noise-macro-name-re, c-noise-macro-with-parens-name-re): New variables.
(c-make-noise-macro-regexps): New function.

* lisp/progmodes/cc-engine.el (c-forward-sws, c-backward-sws): Adapt to treat
members of c-noise-macro-names as whitespace.
(c-forward-noise-clause): New function.
(c-forward-keyword-prefixed-id, c-forward-type, c-forward-declarator)
(c-forward-decl-or-cast-1, c-backward-over-enum-header)
(c-guess-basic-syntax CASE 5A.3, CASE 5A.5, CASE 9A):
Handle "noise clauses" in parallel with, e.g., "hangon key clauses".

* lisp/progmodes/cc-fonts.el (c-complex-decl-matchers): Handle "noise clauses"
in parallel with "prefix-spec keywords".

* lisp/progmodes/cc-mode.el (c-mode, c++-mode, objc-mode): call
c-make-noise-macro-regexps to initialize the internal variables.

* doc/misc/cc-mode.texi ("Noise Macros"): New section documenting the new
facilities.

1 files changed, 63 insertions, 5 deletions

diff --git a/doc/misc/cc-mode.texi b/doc/misc/cc-mode.texi
index bc8d24fd992..cdc659ab358 100644
--- a/doc/misc/cc-mode.texi
+++ b/doc/misc/cc-mode.texi
@@ -338,14 +338,15 @@ Line-Up Functions
 * Comment Line-Up::
 * Misc Line-Up::
 
+
 Customizing Macros
 
 * Macro Backslashes::
 * Macros with ;::
+* Noise Macros::
 
 @end detailmenu
 @end menu
-
 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 @node    Introduction, Overview, Top, Top
 @comment node-name, next, previous, up
@@ -6639,15 +6640,18 @@ Because a macro can expand into anything at all, near where one is
 invoked @ccmode{} can only indent and fontify code heuristically.
 Sometimes it gets it wrong.  Usually you should try to design your
 macros so that they ''look like ordinary code'' when you invoke them.
-However, one situation is so common that @ccmode{} handles it
+However, two situations are so common that @ccmode{} handles them
 specially: that is when certain macros needn't (or mustn't) be
-followed by a @samp{;}.  You need to configure @ccmode{} to handle
-these macros properly, see @ref{Macros with ;}.
+followed by a @samp{;}, and when certain macros (or compiler
+directives) expand to nothing.  You need to configure @ccmode{} to
+handle these macros properly, see @ref{Macros with ;} and @ref{Noise
+Macros}.
 
 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 @menu
 * Macro Backslashes::
 * Macros with ;::
+* Noise Macros::
 @end menu
 
 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
@@ -6699,7 +6703,7 @@ get aligned only when you explicitly invoke the command
 @end defopt
 
 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
-@node Macros with ;,  , Macro Backslashes, Custom Macros
+@node Macros with ;, Noise Macros, Macro Backslashes, Custom Macros
 @comment  node-name,  next,  previous,  up
 @section Macros with semicolons
 @cindex macros with semicolons
@@ -6755,6 +6759,60 @@ initialization code.
 @end defun
 
 @comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+@node    Noise Macros,  , Macros with ;, Custom Macros
+@comment node-name, next, previous, up
+@section Noise Macros
+@cindex noise macros
+@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+In @ccmode{}, @dfn{noise macros} are macros which expand to nothing,
+or compiler directives (such as GCC's @code{__attribute__}) which play
+no part in the syntax of the C (etc.) language.  Some noise macros are
+followed by arguments in parentheses (possibly optionally), others
+are not.
+
+Noise macros can easily confuse @ccmode{}'s analysis of function
+headers, causing them to be mis-fontified, or even mis-indented.  You
+can prevent this confusion by specifying the identifiers which
+constitute noise macros.
+
+@defopt c-noise-macro-names
+@vindex noise-macro-names (c-)
+This variable is a list of names of noise macros which never have
+parenthesized arguments.  Each element is a string, and must be a
+valid identifier.  An element in @code{c-noise-macro-names} must not
+also be in @code{c-noise-macro-with-parens-names}.  Such an element is
+treated as whitespace by @ccmode{}.
+@end defopt
+
+@defopt c-noise-macro-with-parens-names
+@vindex noise-macro-with-parens-names (c-)
+This variable is a list of names of noise macros which optionally have
+arguments in parentheses.  Each element of the list is a string, and
+must be a valid identifier.  An element in
+@code{c-noise-macro-with-parens-names} must not also be in
+@code{c-noise-macro-names}.  For performance reasons, such an element,
+together with the optional parenthesized arguments, is specially
+handled, but it is only handled when used in declaration
+contexts@footnote{If this restriction causes your project
+difficulties, please get in touch with @email{bug-cc-mode@@gnu.org}.}.
+
+The two compiler directives @code{__attribute__} and @code{__declspec}
+have traditionally been handled specially in @ccmode{}; for example
+they are fontified with font-lock-keyword-face.  You don't need to
+include these directives in @code{c-noise-macro-with-parens-names},
+but doing so is OK.
+@end defopt
+
+@defun c-make-noise-macro-regexps
+@findex make-noise-macro-regexps (c-)
+Call this (non-interactive) function, which sets internal variables,
+after changing the value of @code{c-noise-macro-names} or
+@code{c-noise-macro-with-parens-names} (e.g. in a hook (@pxref{CC
+Hooks})).  This function is called by @ccmode{}'s initialization code.
+@end defun
+
+@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 @node    Odds and Ends, Sample Init File, Custom Macros, Top
 @comment node-name, next, previous, up
 @chapter Odds and Ends