Backported triple quote syntax from Emacs 24

1 files changed, 26 insertions, 40 deletions

diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el
index 51f0cfa80eb..247deec6d3e 100644
--- a/lisp/progmodes/python.el
+++ b/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)))