Reported by: Tom Tromey <tromey <at> redhat.com>
Date: Thu, 20 Aug 2009 20:06:04 UTC
Severity: wishlist
Tags: patch
Done: Alan Mackenzie <acm <at> muc.de>
Bug is archived. No further changes may be made.
Message #36 received at 4192 <at> debbugs.gnu.org (full text, mbox):
From: Alan Mackenzie <acm <at> muc.de> To: Lars Ingebrigtsen <larsi <at> gnus.org> Cc: bug-cc-mode <at> gnu.org, Tom Tromey <tom <at> tromey.com>, 4192 <at> debbugs.gnu.org Subject: Re: bug#4192: 23.1; special fontification for "//" in cc-mode Date: Sun, 3 Nov 2019 17:46:18 +0000
Hello, Lars.
On Sun, Nov 03, 2019 at 16:55:42 +0100, Lars Ingebrigtsen wrote:
> Alan Mackenzie <acm <at> muc.de> writes:
> > So, yes, sometime in the very near future, I will implement this.
> Great!
Would you (and anybody else) please review the following patch. Short
instructions on how to enable the feature are in the NEWS alteration;
longer ones are in the cc-mode.texi bit:
diff --git a/doc/misc/cc-mode.texi b/doc/misc/cc-mode.texi
index 217261090b..5ee5540284 100644
--- a/doc/misc/cc-mode.texi
+++ b/doc/misc/cc-mode.texi
@@ -1149,7 +1149,9 @@ Minor Modes
@table @asis
@item comment style
This specifies whether comment commands (such as @kbd{M-;}) insert
-block comments or line comments.
+block comments or line comments.@footnote{You can emphasize
+non-default style comments in your code by giving their delimiters
+@code{font-lock-warning-face}. @xref{Wrong Comment Style}.}
@item electric mode
When this is enabled, certain visible characters cause reformatting as
they are typed. This is normally helpful, but can be a nuisance when
@@ -1866,6 +1868,7 @@ Font Locking
* Font Locking Preliminaries::
* Faces::
* Doc Comments::
+* Wrong Comment Style::
* Misc Font Locking::
* AWK Mode Font Locking::
@end menu
@@ -2069,7 +2072,7 @@ Faces
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
-@node Doc Comments, Misc Font Locking, Faces, Font Locking
+@node Doc Comments, Wrong Comment Style, Faces, Font Locking
@comment node-name, next, previous, up
@section Documentation Comments
@cindex documentation comments
@@ -2149,7 +2152,29 @@ Doc Comments
contributing it: send a note to @email{bug-cc-mode@@gnu.org}.
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
-@node Misc Font Locking, AWK Mode Font Locking, Doc Comments, Font Locking
+@node Wrong Comment Style, Misc Font Locking, Doc Comments, Font Locking
+@comment node-name, next, previous, up
+@section Marking ''Wrong'' style comments
+@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+Most languages supported by @ccmode{} have two styles of comments,
+namely block comments and line comments. Your project may have such a
+strong preference for one of them, that you wish ''wrong'' style
+comments to be clearly marked.
+
+You can get @ccmode{} to do this by setting the default comment style,
+if necessary, (@pxref{Minor Modes}) and setting the customizable
+option @code{c-mark-wrong-style-of-comment} to non-@code{nil}.
+
+@defvar c-mark-wrong-style-of-comment
+@vindex mark-wrong-style-of-comment (c-)
+When this customizable option is non-@code{nil}, comment delimiters
+which aren't of the default style will be fontified with
+@code{font-lock-warning-face}.
+@end defvar
+
+@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+@node Misc Font Locking, AWK Mode Font Locking, Wrong Comment Style, Font Locking
@comment node-name, next, previous, up
@section Miscellaneous Font Locking
@comment !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
diff --git a/etc/NEWS b/etc/NEWS
index 033cb48978..56faf13281 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -2215,6 +2215,14 @@ file-local variable, you may need to update the value.
*** Declare 'define-overload' and 'define-child-mode' as obsolete
*** Rename several internal functions to use a ''mode-local-' prefix
+** CC Mode
+
++++
+*** You can now flag the "wrong style" of comments with
+font-lock-warning-face. To do this, use c-toggle-comment-style, if
+needed, to set the desired default comment style (block or line); then
+set the option c-mark-wrong-style-of-comment to non-nil.
+
* New Modes and Packages in Emacs 27.1
diff --git a/lisp/progmodes/cc-fonts.el b/lisp/progmodes/cc-fonts.el
index c27b70603e..0daea8c84c 100644
--- a/lisp/progmodes/cc-fonts.el
+++ b/lisp/progmodes/cc-fonts.el
@@ -95,6 +95,7 @@
;; during compilation.
(cc-bytecomp-defvar c-preprocessor-face-name)
(cc-bytecomp-defvar c-reference-face-name)
+(cc-bytecomp-defvar c-block-comment-flag)
(cc-bytecomp-defun c-fontify-recorded-types-and-refs)
(cc-bytecomp-defun c-font-lock-declarators)
(cc-bytecomp-defun c-font-lock-objc-method)
@@ -532,7 +533,12 @@ c-fontify-recorded-types-and-refs
(sws-depth (c-lang-const c-syntactic-ws-depth))
(nsws-depth (c-lang-const c-nonempty-syntactic-ws-depth)))
- `(;; The stuff after #error and #warning is a message, so
+ `(;; Fontify "invalid" comment delimiters
+ ,@(when (and (c-lang-const c-block-comment-starter)
+ (c-lang-const c-line-comment-starter))
+ `(c-maybe-font-lock-wrong-style-comments))
+
+ ;; The stuff after #error and #warning is a message, so
;; fontify it as a string.
,@(when (c-lang-const c-cpp-message-directives)
(let* ((re (c-make-keywords-re 'appendable ; nil
@@ -715,6 +721,59 @@ c-font-lock-invalid-single-quotes
(parse-partial-sexp end limit nil nil state 'syntax-table)))
nil)
+(defun c-maybe-font-lock-wrong-style-comments (limit)
+ ;; This function will be called from font-lock-for a region bounded by POINT
+ ;; and LIMIT, as though it were to identify a keyword for
+ ;; font-lock-keyword-face. It always returns NIL to inhibit this and
+ ;; prevent a repeat invocation. See elisp/lispref page "Search-based
+ ;; Fontification".
+ ;;
+ ;; This function fontifies "invalid" comment delimiters with
+ ;; `font-lock-warning-face'. A delimiter is "invalid" when
+ ;; `c-mark-wrong-style-of-comment' is non-nil, and the delimiter style is
+ ;; not the default specified by `c-block-comment-flag'.
+ (when c-mark-wrong-style-of-comment
+ (let* ((lit (c-semi-pp-to-literal (point)))
+ (s (car lit)) ; parse-partial-sexp state.
+ )
+ ;; First, deal with and move out of any literal we start in.
+ (cond
+ ((null (cadr lit))) ; Not in a literal
+ ((eq (cadr lit) 'string)
+ (setq s (parse-partial-sexp (point) limit nil nil s 'syntax-table)))
+ ((and (not c-block-comment-flag) ; In an "invalid" block comment
+ (eq (cadr lit) 'c))
+ (setq s (parse-partial-sexp (point) limit nil nil s 'syntax-table))
+ ;; Font lock the block comment ender with warning face.
+ (when (not (nth 4 s))
+ (c-put-font-lock-face (- (point) (length c-block-comment-ender))
+ (point) font-lock-warning-face)))
+ (t ; In a line comment, or a "valid" block comment
+ (setq s (parse-partial-sexp (point) limit nil nil s 'syntax-table))))
+
+ (while (< (point) limit)
+ (setq s (parse-partial-sexp (point) limit nil nil s 'syntax-table))
+ (cond
+ ((or (nth 3 s) ; In a string
+ (and (nth 4 s) ; In a comment
+ (eq (nth 7 s) ; Comment style
+ (if c-block-comment-flag
+ nil ; Block comment
+ 1)))) ; Line comment
+ ;; Move over a "valid" literal.
+ (setq s (parse-partial-sexp (point) limit nil nil s 'syntax-table)))
+ ((nth 4 s) ; In an invalid comment
+ ;; Fontify the invalid comment opener.
+ (c-put-font-lock-face (nth 8 s) (point) font-lock-warning-face)
+ ;; Move to end of comment or LIMIT.
+ (setq s (parse-partial-sexp (point) limit nil nil s 'syntax-table))
+ ;; Fontify an invalid block comment ender, if that's what we have.
+ (when (and (not c-block-comment-flag)
+ (not (nth 4 s))) ; We're outside the comment
+ (c-put-font-lock-face (- (point) (length c-block-comment-ender))
+ (point) font-lock-warning-face)))))))
+ nil)
+
(c-lang-defconst c-basic-matchers-before
"Font lock matchers for basic keywords, labels, references and various
other easily recognizable things that should be fontified before generic
diff --git a/lisp/progmodes/cc-vars.el b/lisp/progmodes/cc-vars.el
index 60ad42f24f..273174e041 100644
--- a/lisp/progmodes/cc-vars.el
+++ b/lisp/progmodes/cc-vars.el
@@ -1751,6 +1751,14 @@ c-make-macro-with-semi-re
c-macro-names-with-semicolon: %s"
c-macro-names-with-semicolon))))))
+(defcustom c-mark-wrong-style-of-comment nil
+ "Fontify \"invalid\" comment delims with `font-lock-warning-face' if non-nil.
+\"Invalid\" means a line comment when the default comment style (set by
+`c-toggle-comment-style') is block, or a block comment otherwise."
+ :type 'boolean
+ :group 'c
+ :version 27.1)
+
(defvar c-file-style nil
"Variable interface for setting style via File Local Variables.
In a file's Local Variable section, you can set this variable to a
> --
> (domestic pets only, the antidote for overdose, milk.)
> bloggy blog: http://lars.ingebrigtsen.no
--
Alan Mackenzie (Nuremberg, Germany).
GNU bug tracking system
Copyright (C) 1999 Darren O. Benham,
1997,2003 nCipher Corporation Ltd,
1994-97 Ian Jackson.