X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/21733e4f154f8830fa568a347a0d6dbd59793c2b..bb8097b96b074e55ff05dc379b394dbdbdc82f3e:/lisp/newcomment.el

diff --git a/lisp/newcomment.el b/lisp/newcomment.el
index bcb5f721ae..251c160534 100644
--- a/lisp/newcomment.el
+++ b/lisp/newcomment.el
@@ -435,18 +435,23 @@ If UNP is non-nil, unquote nested comment markers."
 ;;;; Navigation
 ;;;;
 
-(defvar comment-use-global-state nil
+(defvar comment-use-global-state t
   "Non-nil means that the global syntactic context is used.
 More specifically, it means that `syntax-ppss' is used to find out whether
-point is within a string or not.  Major modes whose syntax is faithfully
-described by the syntax-tables can set this to non-nil so comment markers
-in strings will not confuse Emacs.")
+point is within a string or not.  Major modes whose syntax is not faithfully
+described by the syntax-tables (or where `font-lock-syntax-table' is radically
+different from the main syntax table) can set this to nil,
+then `syntax-ppss' cache won't be used in comment-related routines.")
+
+(make-obsolete-variable 'comment-use-global-state 'comment-use-syntax "24.4")
 
 (defun comment-search-forward (limit &optional noerror)
   "Find a comment start between point and LIMIT.
 Moves point to inside the comment and returns the position of the
 comment-starter.  If no comment is found, moves point to LIMIT
-and raises an error or returns nil if NOERROR is non-nil."
+and raises an error or returns nil if NOERROR is non-nil.
+
+Ensure that `comment-normalize-vars' has been called before you use this."
   (if (not comment-use-syntax)
       (if (re-search-forward comment-start-skip limit noerror)
 	  (or (match-end 1) (match-beginning 0))
@@ -484,7 +489,9 @@ and raises an error or returns nil if NOERROR is non-nil."
   "Find a comment start between LIMIT and point.
 Moves point to inside the comment and returns the position of the
 comment-starter.  If no comment is found, moves point to LIMIT
-and raises an error or returns nil if NOERROR is non-nil."
+and raises an error or returns nil if NOERROR is non-nil.
+
+Ensure that `comment-normalize-vars' has been called before you use this."
   ;; FIXME: If a comment-start appears inside a comment, we may erroneously
   ;; stop there.  This can be rather bad in general, but since
   ;; comment-search-backward is only used to find the comment-column (in
@@ -511,30 +518,36 @@ and raises an error or returns nil if NOERROR is non-nil."
   "Find the beginning of the enclosing comment.
 Returns nil if not inside a comment, else moves point and returns
 the same as `comment-search-backward'."
-  ;; HACK ATTACK!
-  ;; We should really test `in-string-p' but that can be expensive.
-  (unless (eq (get-text-property (point) 'face) 'font-lock-string-face)
-    (let ((pt (point))
-	  (cs (comment-search-backward nil t)))
-      (when cs
-	(if (save-excursion
-	      (goto-char cs)
-	      (and
-	       ;; For modes where comment-start and comment-end are the same,
-	       ;; the search above may have found a `ce' rather than a `cs'.
-	       (or (if comment-end-skip (not (looking-at comment-end-skip)))
-		   ;; Maybe font-lock knows that it's a `cs'?
-		   (eq (get-text-property (match-end 0) 'face)
-		       'font-lock-comment-face)
-		   (unless (eq (get-text-property (point) 'face)
-			       'font-lock-comment-face)
-		     ;; Let's assume it's a `cs' if we're on the same line.
-		     (>= (line-end-position) pt)))
-	       ;; Make sure that PT is not past the end of the comment.
-	       (if (comment-forward 1) (> (point) pt) (eobp))))
-	    cs
-	  (goto-char pt)
-	  nil)))))
+  (if (and comment-use-syntax comment-use-global-state)
+      (let ((state (syntax-ppss)))
+        (when (nth 4 state)
+          (goto-char (nth 8 state))
+          (prog1 (point)
+            (when (looking-at comment-start-skip)
+              (goto-char (match-end 0))))))
+    ;; Can't rely on the syntax table, let's guess based on font-lock.
+    (unless (eq (get-text-property (point) 'face) 'font-lock-string-face)
+      (let ((pt (point))
+            (cs (comment-search-backward nil t)))
+        (when cs
+          (if (save-excursion
+                (goto-char cs)
+                (and
+                 ;; For modes where comment-start and comment-end are the same,
+                 ;; the search above may have found a `ce' rather than a `cs'.
+                 (or (if comment-end-skip (not (looking-at comment-end-skip)))
+                     ;; Maybe font-lock knows that it's a `cs'?
+                     (eq (get-text-property (match-end 0) 'face)
+                         'font-lock-comment-face)
+                     (unless (eq (get-text-property (point) 'face)
+                                 'font-lock-comment-face)
+                       ;; Let's assume it's a `cs' if we're on the same line.
+                       (>= (line-end-position) pt)))
+                 ;; Make sure that PT is not past the end of the comment.
+                 (if (comment-forward 1) (> (point) pt) (eobp))))
+              cs
+            (goto-char pt)
+            nil))))))
 
 (defun comment-forward (&optional n)
   "Skip forward over N comments.