Backported triple quote syntax from Emacs 24

lisp/progmodes/python.el

@@ -395,26 +395,15 @@
               (set-match-data nil)))))
      (1 font-lock-variable-name-face nil nil))))
 
-;; Fixme: Is there a better way?
 (defconst python-font-lock-syntactic-keywords
+  ;; Make outer chars of matching triple-quote sequences into generic
+  ;; string delimiters.  Fixme: Is there a better way?
   ;; First avoid a sequence preceded by an odd number of backslashes.
-  `((,(rx (not (any ?\\))
-	  ?\\ (* (and ?\\ ?\\))
-	  (group (syntax string-quote))
-	  (backref 1)
-	  (group (backref 1)))
-     (2 ,(string-to-syntax "\"")))	; dummy
-    (,(rx (group (optional (any "uUrR"))) ; prefix gets syntax property
-	  (optional (any "rR"))		  ; possible second prefix
-	  (group (syntax string-quote))   ; maybe gets property
-	  (backref 2)			  ; per first quote
-	  (group (backref 2)))		  ; maybe gets property
-     (1 (python-quote-syntax 1))
-     (2 (python-quote-syntax 2))
-     (3 (python-quote-syntax 3))))
-  "Make outer chars of triple-quote strings into generic string delimiters.")
-
-(defun python-quote-syntax (n)
+  `((,(concat "\\(?:\\([RUru]\\)[Rr]?\\|^\\|[^\\]\\(?:\\\\.\\)*\\)" ;Prefix.
+            "\\(?:\\('\\)'\\('\\)\\|\\(?2:\"\\)\"\\(?3:\"\\)\\)")
+     (3 (python-quote-syntax)))))
+
+(defun python-quote-syntax ()
   "Put `syntax-table' property correctly on triple quote.
 Used for syntactic keywords.  N is the match number (1, 2 or 3)."
   ;; Given a triple quote, we have to check the context to know
@@ -432,28 +421,25 @@ Used for syntactic keywords.  N is the match number (1, 2 or 3)."
   ;; x '"""' x """ \"""" x
   (save-excursion
     (goto-char (match-beginning 0))
-    (cond
-     ;; Consider property for the last char if in a fenced string.
-     ((= n 3)
-      (let* ((font-lock-syntactic-keywords nil)
-	     (syntax (syntax-ppss)))
-	(when (eq t (nth 3 syntax))	; after unclosed fence
-	  (goto-char (nth 8 syntax))	; fence position
-	  (skip-chars-forward "uUrR")	; skip any prefix
-	  ;; Is it a matching sequence?
-	  (if (eq (char-after) (char-after (match-beginning 2)))
-	      (eval-when-compile (string-to-syntax "|"))))))
-     ;; Consider property for initial char, accounting for prefixes.
-     ((or (and (= n 2)			; leading quote (not prefix)
-	       (= (match-beginning 1) (match-end 1))) ; prefix is null
-	  (and (= n 1)			; prefix
-	       (/= (match-beginning 1) (match-end 1)))) ; non-empty
-      (let ((font-lock-syntactic-keywords nil))
-	(unless (eq 'string (syntax-ppss-context (syntax-ppss)))
-	  (eval-when-compile (string-to-syntax "|")))))
-     ;; Otherwise (we're in a non-matching string) the property is
-     ;; nil, which is OK.
-     )))
+    (let ((syntax (save-match-data (syntax-ppss))))
+      (cond
+       ((eq t (nth 3 syntax))           ; after unclosed fence
+        ;; Consider property for the last char if in a fenced string.
+        (goto-char (nth 8 syntax))	; fence position
+        (skip-chars-forward "uUrR")	; skip any prefix
+        ;; Is it a matching sequence?
+        (if (eq (char-after) (char-after (match-beginning 2)))
+            (put-text-property (match-beginning 3) (match-end 3)
+                               'syntax-table (string-to-syntax "|"))))
+       ((match-end 1)
+        ;; Consider property for initial char, accounting for prefixes.
+        (put-text-property (match-beginning 1) (match-end 1)
+                           'syntax-table (string-to-syntax "|")))
+       (t
+        ;; Consider property for initial char, accounting for prefixes.
+        (put-text-property (match-beginning 2) (match-end 2)
+                           'syntax-table (string-to-syntax "|"))))
+      )))
 
 (defvar python-mode-syntax-table
   (let ((table (make-syntax-table)))