fixing triple quoted strings issue with code from python-mode

coffee-mode.el

@@ -656,6 +656,50 @@ line? Returns `t' or `nil'. See the README for more details."
     (backward-to-indentation 0)
     (= (char-after) (string-to-char "#"))))
 
+
+(defun coffee-quote-syntax (n)
+  "Put `syntax-table' property correctly on triple quote.
+Used for syntactic keywords.  N is the match number (1, 2 or 3)."
+  ;; From python-mode...
+  ;;
+  ;; Given a triple quote, we have to check the context to know
+  ;; whether this is an opening or closing triple or whether it's
+  ;; quoted anyhow, and should be ignored.  (For that we need to do
+  ;; the same job as `syntax-ppss' to be correct and it seems to be OK
+  ;; to use it here despite initial worries.)  We also have to sort
+  ;; out a possible prefix -- well, we don't _have_ to, but I think it
+  ;; should be treated as part of the string.
+
+  ;; Test cases:
+  ;;  ur"""ar""" x='"' # """
+  ;; x = ''' """ ' a
+  ;; '''
+  ;; 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)
+	       (not (match-end 1)))     ; prefix is null
+	  (and (= n 1)			; prefix
+	       (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.
+     )))
+
 ;;
 ;; Define Major Mode
 ;;
@@ -685,6 +729,16 @@ line? Returns `t' or `nil'. See the README for more details."
   ;; single quote strings
   (modify-syntax-entry ?' "\"" coffee-mode-syntax-table)
 
+  (setq font-lock-syntactic-keywords
+        ;; Make outer chars of matching triple-quote sequences into generic
+        ;; string delimiters.
+        ;; First avoid a sequence preceded by an odd number of backslashes.
+        `((,(concat "\\(?:^\\|[^\\]\\(?:\\\\.\\)*\\)" ;Prefix.
+                    "\\(?:\\('\\)\\('\\)\\('\\)\\|\\(?1:\"\\)\\(?2:\"\\)\\(?3:\"\\)\\)")
+           (1 (coffee-quote-syntax 1) nil lax)
+           (2 (coffee-quote-syntax 2))
+           (3 (coffee-quote-syntax 3)))))
+
   ;; indentation
   (make-local-variable 'indent-line-function)
   (setq indent-line-function 'coffee-indent-line)