Re: Two more CC Mode bugs fixed. For Emacs 26?

[Alan Mackenzie <acm@muc.de>]

Hello, Eli.

On Wed, Dec 20, 2017 at 17:52:08 +0200, Eli Zaretskii wrote:
> > Date: Tue, 19 Dec 2017 19:52:05 +0000
> > From: Alan Mackenzie <acm@muc.de>
> > Cc: John Ciolfi <John.Ciolfi@mathworks.com>

> > I'd like to commit these two fixes to the release branch.  1/- because
> > it is relatively important, and 2/- because it is cheap and very low
> > risk.

> > What do people, Eli and others, say?

> Sounds good, but please show the patches first.

OK, here goes.  Please don't be put off by the length of the first
patch - about half of it is just the removal of now redundant macros,
and renaming c-neutralize-syntax-in-and-mark-CPP to remove the
"and-mark-" bit.  Also, that first patch doesn't apply cleanly to the
emacs-26 branch.  Sorry about that.

#########################################################################

1/- [Problem: #include "b.hpp"//Comment misfontifies because of lack of
a space before the comment.]


Fontify a CPP construct correctly when a comment follows without spaces

Do this by removing a broken optimization in the state cache which put
category text properties on a character between the end of the CPP construct
and the beginning of the comment.  This can't work when there's no such
character.

* cc-defs.el (c-cpp-delimiter, c-set-cpp-delimiters,
* c-clear-cpp-delimiters)
(c-comment-out-cpps, c-with-cpps-commented-out)
(c-with-all-but-one-cpps-commented-out): Remove.

* cc-engine.el (c-no-comment-end-of-macro): Return the comment start position
rather than one character before it.
(c-invalidate-state-cache, c-parse-state): Remove the invocations of
c-with-all-but-one-cpps-commented-out and c-with-cpps-commented-out.

* cc-mode.el (c-neutralize-syntax-in-and-mark-CPP): Rename to
c-neutralize-syntax-in-CPP and remove the bits which applied category
properties.

* cc-langs.el (c-before-font-lock-functions): Incorporate the new name of the
function c-neutralize-syntax-in-CPP.



diff -r 0ca472c82800 cc-defs.el
--- a/cc-defs.el	Thu Dec 14 20:55:20 2017 +0000
+++ b/cc-defs.el	Sat Dec 16 18:43:22 2017 +0000
@@ -1417,59 +1417,6 @@
 
 ;;;;;;;;;;;;;;;
 
-(defconst c-cpp-delimiter '(14)) ; generic comment syntax
-;; This is the value of the `category' text property placed on every #
-;; which introduces a CPP construct and every EOL (or EOB, or character
-;; preceding //, etc.) which terminates it.  We can instantly "comment
-;; out" all CPP constructs by giving `c-cpp-delimiter' a syntax-table
-;; property '(14) (generic comment delimiter).
-(defmacro c-set-cpp-delimiters (beg end)
-  ;; This macro does a hidden buffer change.
-  `(progn
-     (c-put-char-property ,beg 'category 'c-cpp-delimiter)
-     (if (< ,end (point-max))
-	 (c-put-char-property ,end 'category 'c-cpp-delimiter))))
-(defmacro c-clear-cpp-delimiters (beg end)
-  ;; This macro does a hidden buffer change.
-  `(progn
-     (c-clear-char-property ,beg 'category)
-     (if (< ,end (point-max))
-	 (c-clear-char-property ,end 'category))))
-
-(defsubst c-comment-out-cpps ()
-  ;; Render all preprocessor constructs syntactically commented out.
-  (put 'c-cpp-delimiter 'syntax-table c-cpp-delimiter))
-(defsubst c-uncomment-out-cpps ()
-  ;; Restore the syntactic visibility of preprocessor constructs.
-  (put 'c-cpp-delimiter 'syntax-table nil))
-
-(defmacro c-with-cpps-commented-out (&rest forms)
-  ;; Execute FORMS... whilst the syntactic effect of all characters in
-  ;; all CPP regions is suppressed.  In particular, this is to suppress
-  ;; the syntactic significance of parens/braces/brackets to functions
-  ;; such as `scan-lists' and `parse-partial-sexp'.
-  `(unwind-protect
-       (c-save-buffer-state ()
-	   (c-comment-out-cpps)
-	   ,@forms)
-     (c-save-buffer-state ()
-       (c-uncomment-out-cpps))))
-
-(defmacro c-with-all-but-one-cpps-commented-out (beg end &rest forms)
-  ;; Execute FORMS... whilst the syntactic effect of all characters in
-  ;; every CPP region APART FROM THE ONE BETWEEN BEG and END is
-  ;; suppressed.
-  `(unwind-protect
-       (c-save-buffer-state ()
-	 (save-restriction
-	   (widen)
-	   (c-clear-cpp-delimiters ,beg ,end))
-	 ,`(c-with-cpps-commented-out ,@forms))
-     (c-save-buffer-state ()
-       (save-restriction
-	 (widen)
-	 (c-set-cpp-delimiters ,beg ,end)))))
-
 (defmacro c-self-bind-state-cache (&rest forms)
   ;; Bind the state cache to itself and execute the FORMS.  Return the result
   ;; of the last FORM executed.  It is assumed that no buffer changes will
diff -r 0ca472c82800 cc-engine.el
--- a/cc-engine.el	Thu Dec 14 20:55:20 2017 +0000
+++ b/cc-engine.el	Sat Dec 16 18:43:22 2017 +0000
@@ -243,8 +243,8 @@
 ;; `c-macro-cache'.
 (defvar c-macro-cache-no-comment nil)
 (make-variable-buffer-local 'c-macro-cache-no-comment)
-;; Either nil, or the last character of the macro currently represented by
-;; `c-macro-cache' which isn't in a comment. */
+;; Either nil, or the position of a comment which is open at the end of the
+;; macro represented by `c-macro-cache'.
 
 (defun c-invalidate-macro-cache (beg end)
   ;; Called from a before-change function.  If the change region is before or
@@ -387,8 +387,9 @@
     (point)))
 
 (defun c-no-comment-end-of-macro ()
-  ;; Go to the end of a CPP directive, or a pos just before which isn't in a
-  ;; comment.  For this purpose, open strings are ignored.
+  ;; Go to the start of the comment which is open at the end of the current
+  ;; CPP directive, or to the end of that directive.  For this purpose, open
+  ;; strings are ignored.
   ;;
   ;; This function must only be called from the beginning of a CPP construct.
   ;;
@@ -406,7 +407,7 @@
 	(setq s (parse-partial-sexp here there)))
       (when (and (nth 4 s)
 		 (not (eq (nth 7 s) 'syntax-table))) ; no pseudo comments.
-	(goto-char (1- (nth 8 s))))
+	(goto-char (nth 8 s)))
       (setq c-macro-cache-no-comment (point)))
     (point)))
 
@@ -3864,14 +3865,7 @@
   (if (memq 'category-properties c-emacs-features)
       ;; Emacs
       (c-with-<->-as-parens-suppressed
-       (if (and c-state-old-cpp-beg
-		(< c-state-old-cpp-beg here))
-	   (c-with-all-but-one-cpps-commented-out
-	    c-state-old-cpp-beg
-	    c-state-old-cpp-end
-	    (c-invalidate-state-cache-1 here))
-	 (c-with-cpps-commented-out
-	  (c-invalidate-state-cache-1 here))))
+       (c-invalidate-state-cache-1 here))
     ;; XEmacs
     (c-invalidate-state-cache-1 here)))
 
@@ -3905,12 +3899,7 @@
 	(if (memq 'category-properties c-emacs-features)
 	    ;; Emacs
 	    (c-with-<->-as-parens-suppressed
-	     (if (and here-cpp-beg (> here-cpp-end here-cpp-beg))
-		 (c-with-all-but-one-cpps-commented-out
-		  here-cpp-beg here-cpp-end
-		  (c-parse-state-1))
-	       (c-with-cpps-commented-out
-		(c-parse-state-1))))
+	     (c-parse-state-1))
 	  ;; XEmacs
 	  (c-parse-state-1))
       (setq c-state-old-cpp-beg
diff -r 0ca472c82800 cc-langs.el
--- a/cc-langs.el	Thu Dec 14 20:55:20 2017 +0000
+++ b/cc-langs.el	Sat Dec 16 18:43:22 2017 +0000
@@ -502,13 +502,13 @@
   (c objc) '(c-depropertize-new-text
 	     c-parse-quotes-after-change
 	     c-extend-font-lock-region-for-macros
-	     c-neutralize-syntax-in-and-mark-CPP
+	     c-neutralize-syntax-in-CPP
 	     c-change-expand-fl-region)
   c++ '(c-depropertize-new-text
 	c-parse-quotes-after-change
 	c-extend-font-lock-region-for-macros
 	c-after-change-re-mark-raw-strings
-	c-neutralize-syntax-in-and-mark-CPP
+	c-neutralize-syntax-in-CPP
 	c-restore-<>-properties
 	c-change-expand-fl-region)
   java '(c-depropertize-new-text
diff -r 0ca472c82800 cc-mode.el
--- a/cc-mode.el	Thu Dec 14 20:55:20 2017 +0000
+++ b/cc-mode.el	Sat Dec 16 18:43:22 2017 +0000
@@ -1002,15 +1002,10 @@
 	      t)
 	     (t nil)))))))
 
-(defun c-neutralize-syntax-in-and-mark-CPP (begg endd old-len)
-  ;; (i) "Neutralize" every preprocessor line wholly or partially in the
-  ;; changed region.  "Restore" lines which were CPP lines before the change
-  ;; and are no longer so.
-  ;;
-  ;; (ii) Mark each CPP construct by placing a `category' property value
-  ;; `c-cpp-delimiter' at its start and end.  The marked characters are the
-  ;; opening # and usually the terminating EOL, but sometimes the character
-  ;; before a comment delimiter.
+(defun c-neutralize-syntax-in-CPP (begg endd old-len)
+  ;; "Neutralize" every preprocessor line wholly or partially in the changed
+  ;; region.  "Restore" lines which were CPP lines before the change and are
+  ;; no longer so.
   ;;
   ;; That is, set syntax-table properties on characters that would otherwise
   ;; interact syntactically with those outside the CPP line(s).
@@ -1030,11 +1025,7 @@
   (c-save-buffer-state (limits)
     ;; Clear 'syntax-table properties "punctuation":
     ;; (c-clear-char-property-with-value c-new-BEG c-new-END 'syntax-table '(1))
-
-    ;; CPP "comment" markers:
-    (if (memq 'category-properties c-emacs-features) ; GNU Emacs.
-	(c-clear-char-property-with-value
-	 c-new-BEG c-new-END 'category 'c-cpp-delimiter))
+    ;; The above is now done in `c-depropertize-CPP'.
 
     ;; Add needed properties to each CPP construct in the region.
     (goto-char c-new-BEG)
@@ -1061,10 +1052,7 @@
 	  (goto-char (match-beginning 1))
 	  (setq mbeg (point))
 	  (if (> (c-no-comment-end-of-macro) mbeg)
-	      (progn
-		(c-neutralize-CPP-line mbeg (point)) ; "punctuation" properties
-		(if (memq 'category-properties c-emacs-features) ; GNU Emacs.
-		    (c-set-cpp-delimiters mbeg (point)))) ; "comment" markers
+	      (c-neutralize-CPP-line mbeg (point)) ; "punctuation" properties
 	    (forward-line))	      ; no infinite loop with, e.g., "#//"
 	  )))))
  
#########################################################################

2/- [Problem: doc comments don't get fontified when the doc comment
opener immediately follows a literal without intervening whitespace.]

Fix loss of documentation face in certain CC Mode doc comment situations

* cc-fonts.el (c-font-lock-doc-comments): Take into account the possibility of
font-lock-comment-delimiter-face.  Test rigorously for "/**" (etc.) being
itself inside a literal, rather than just depending on the face of the
previous character.



diff -r 0ca472c82800 cc-fonts.el
--- a/cc-fonts.el	Thu Dec 14 20:55:20 2017 +0000
+++ b/cc-fonts.el	Sun Dec 17 20:31:08 2017 +0000
@@ -2666,8 +2666,8 @@
   ;; This function might do hidden buffer changes.
 
   (let (comment-beg region-beg)
-    (if (eq (get-text-property (point) 'face)
-	    'font-lock-comment-face)
+    (if (memq (get-text-property (point) 'face)
+	      '(font-lock-comment-face font-lock-comment-delimiter-face))
 	;; Handle the case when the fontified region starts inside a
 	;; comment.
 	(let ((start (c-literal-start)))
@@ -2687,8 +2687,15 @@
 		     (or (not (c-got-face-at comment-beg
 					     c-literal-faces))
 			 (and (/= comment-beg (point-min))
+			      ;; Cheap check which is unreliable (the previous
+			      ;; character could be the end of a previous
+			      ;; comment).
 			      (c-got-face-at (1- comment-beg)
-					     c-literal-faces))))
+					     c-literal-faces)
+			      ;; Expensive reliable check.
+			      (save-excursion
+				(goto-char comment-beg)
+				(c-in-literal)))))
 	      (setq comment-beg nil))
 	    (setq region-beg comment-beg))
  
#########################################################################


> Thanks.

Thank you!

-- 
Alan Mackenzie (Nuremberg, Germany).