Re: [PATCH] let octave-mode understand single-quoted strings

[Stefan Monnier]

>> I just implemented the single-quote string support based
>> on code I previously wrote for perl-mode, where it's used for
>> string-like thingies that often span multiple lines.  I.e. it came "for
>> free".
> The thing is that Matlab has a quirk where a' means the transpose of a
> and 'a' means the string containing a, and Octave inherits this
> syntax. That's the trickiest thing about single-quote strings in
> Octave (and why Octave sources encourage using double-quote strings
> all the time).

Right.

> I still don't get why this is related to multiline issues, though.

It's not directly related.

> Where is your patch?

In Emacs's trunk.  See below.
BTW, where can I find a definition of the syntax of single-quoted
strings (i.e. how does Octave distinguish a transpose from a single-quote
starting a string)?
The Octave docs I have don't say anything about it, AFAICT.


        Stefan


=== modified file 'lisp/progmodes/octave-mod.el'
--- lisp/progmodes/octave-mod.el        2010-08-12 14:44:16 +0000
+++ lisp/progmodes/octave-mod.el        2010-08-17 15:49:30 +0000
@@ -181,6 +179,30 @@
         '(3 font-lock-function-name-face nil t)))
   "Additional Octave expressions to highlight.")
 
+(defvar octave-font-lock-syntactic-keywords
+  ;; Try to distinguish the string-quotes from the transpose-quotes.
+  '(("[[({,; ]\\('\\)" (1 "\"'"))
+    (octave-font-lock-close-quotes)))
+
+(defun octave-font-lock-close-quotes (limit)
+  "Fix the syntax-table of the closing quotes of single-quote strings."
+  ;; Freely inspired from perl-font-lock-special-syntactic-constructs.
+  (let ((state (syntax-ppss)))
+    (while (< (point) limit)
+      (cond
+       ((eq (nth 3 state) ?\')
+        ;; A '..' string.
+        (save-excursion
+          (when (and (or (looking-at "\\('\\)")
+                         (re-search-forward "[^\\]\\(?:\\\\\\\\\\)*\\('\\)"
+                                            nil t))
+                     (not (eobp)))
+            (put-text-property (match-beginning 1) (match-end 1)
+                               'syntax-table (string-to-syntax "\"'"))))))
+
+      (setq state (parse-partial-sexp (point) limit nil nil state
+                                     'syntax-table)))))
+
 (defcustom inferior-octave-buffer "*Inferior Octave*"
   "Name of buffer for running an inferior Octave process."
   :type 'string