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, 43 insertions, 0 deletions

diff --git a/lisp/progmodes/cc-vars.el b/lisp/progmodes/cc-vars.el
index 8cee733ec8e..a6957185a2b 100644
--- a/lisp/progmodes/cc-vars.el
+++ b/lisp/progmodes/cc-vars.el
@@ -1619,6 +1619,49 @@ names)."))
   :type 'c-extra-types-widget
   :group 'c)
 
+(defvar c-noise-macro-with-parens-name-re nil)
+(defvar c-noise-macro-name-re nil)
+
+(defcustom c-noise-macro-names nil
+  "A list of names of macros which expand to nothing, or compiler extensions
+like \"????\" which are syntactic noise.  Such a macro/extension is complete in
+itself, never having parentheses.  All these names must be syntactically valid
+identifiers.
+
+If you change this variable's value, call the function
+`c-make-noise-macro-regexps' to set the necessary internal variables (or do
+this implicitly by reinitialising C/C++/Objc Mode on any buffer)."
+  :type '(repeat :tag "List of names" string)
+  :group 'c)
+
+(defcustom c-noise-macro-with-parens-names nil
+  "A list of names of macros \(or compiler extensions like \"__attribute__\")
+which optionally have arguments in parentheses, and which expand to nothing.
+These are recognized by CC Mode only in declarations."
+  :type '(regexp :tag "List of names (possibly empty)" string)
+  :group 'c)
+
+(defun c-make-noise-macro-regexps ()
+  ;; Convert `c-noise-macro-names' and `c-noise-macro-with-parens-names' into
+  ;; `c-noise-macro-name-re' and `c-noise-macro-with-parens-name-re'.
+  (setq c-noise-macro-with-parens-name-re
+	(cond ((null c-noise-macro-with-parens-names) "\\<\\>")
+	      ((consp c-noise-macro-with-parens-names)
+	       (concat (regexp-opt c-noise-macro-with-parens-names t)
+		       "\\([^[:alnum:]_$]\\|$\\)"))
+	      ((stringp c-noise-macro-with-parens-names)
+	       (copy-sequence c-noise-macro-with-parens-names))
+	      (t (error "c-make-noise-macro-regexps: \
+c-noise-macro-with-parens-names is invalid: %s" c-noise-macro-with-parens-names))))
+  (setq c-noise-macro-name-re
+	(cond ((null c-noise-macro-names) "\\<\\>")
+	      ((consp c-noise-macro-names)
+	       (concat (regexp-opt c-noise-macro-names t)
+		       "\\([^[:alnum:]_$]\\|$\\)"))
+	      ((stringp c-noise-macro-names)
+	       (copy-sequence c-noise-macro-names))
+	      (t (error "c-make-noise-macro-regexps: \
+c-noise-macro-names is invalid: %s" c-noise-macro-names)))))
 
 ;; Non-customizable variables, still part of the interface to CC Mode
 (defvar c-macro-with-semi-re nil