bug#7735: A questing mark at the end of a string in ruby-mode

bug#7735: A questing mark at the end of a string in ruby-mode

[Lennart Borgman]

A question mark at the end of a string makes ruby-mode believe the
string does not end there.

To show this place the following in a ruby-mode buffer:

  re_str = wild.join(".*?")
  re = Regexp.new(re_str, 1)


GNU Emacs 24.0.50.1 (i386-mingw-nt5.1.2600) of 2010-12-15

bug#7735: A questing mark at the end of a string in ruby-mode

[Chong Yidong]

Lennart Borgman <lennart.borgman@gmail.com> writes:

> A question mark at the end of a string makes ruby-mode believe the
> string does not end there.
>
> To show this place the following in a ruby-mode buffer:
>
>   re_str = wild.join(".*?")
>   re = Regexp.new(re_str, 1)

This bug was appeared during the introduction of syntax-propertize.
Stefan, could you take a look?

2010-09-10  Stefan Monnier  <monnier@iro.umontreal.ca>

  * progmodes/ruby-mode.el (ruby-here-doc-beg-re):
  Define while compiling.
  (ruby-here-doc-end-re, ruby-here-doc-beg-match)
  (ruby-font-lock-syntactic-keywords, ruby-comment-beg-syntax)
  (syntax-ppss, ruby-in-ppss-context-p, ruby-in-here-doc-p)
  (ruby-here-doc-find-end, ruby-here-doc-beg-syntax)
  (ruby-here-doc-end-syntax): Only define when
  syntax-propertize is not available.
  (ruby-syntax-propertize-function, ruby-syntax-propertize-heredoc):
  New functions.
  (ruby-in-ppss-context-p): Update to new syntax of heredocs.
  (electric-indent-chars): Silence bytecompiler.
  (ruby-mode): Use prog-mode, syntax-propertize-function, and
  electric-indent-chars.

bug#7735: A questing mark at the end of a string in ruby-mode

[Stefan Monnier]

> A question mark at the end of a string makes ruby-mode believe the
> string does not end there.

Indeed, when I switched to syntax-propertize-rules code, I didn't notice
that one of the regexps use backrefs, which aren't supported by
syntax-propertize-rules.
I've just installed the patch below which should fix it,


        Stefan


=== modified file 'lisp/progmodes/ruby-mode.el'
--- lisp/progmodes/ruby-mode.el	2011-01-16 02:21:30 +0000
+++ lisp/progmodes/ruby-mode.el	2011-01-24 19:47:16 +0000
@@ -1121,14 +1121,13 @@
          (syntax-propertize-rules
           ;; #{ }, #$hoge, #@foo are not comments
           ("\\(#\\)[{$@]" (1 "."))
-          ;; the last $', $", $` in the respective string is not variable
-          ;; the last ?', ?", ?` in the respective string is not ascii code
-          ("\\(^\\|[\[ \t\n<+\(,=]\\)\\(['\"`]\\)\\(\\\\.\\|\\2\\|[^'\"`\n\\\\]\\)*?\\\\?[?$]\\(\\2\\)"
-           (2 "\"")
-           (4 "\""))
           ;; $' $" $` .... are variables
           ;; ?' ?" ?` are ascii codes
-          ("\\(^\\|[^\\\\]\\)\\(\\\\\\\\\\)*[?$]\\([#\"'`]\\)" (3 "."))
+          ("\\([?$]\\)[#\"'`]"
+           (1 (unless (save-excursion
+                        ;; Not within a string.
+                        (nth 3 (syntax-ppss (match-beginning 0))))
+                (string-to-syntax "\\"))))
           ;; regexps
           ("\\(^\\|[=(,~?:;<>]\\|\\(^\\|\\s \\)\\(if\\|elsif\\|unless\\|while\\|until\\|when\\|and\\|or\\|&&\\|||\\)\\|g?sub!?\\|scan\\|split!?\\)\\s *\\(/\\)[^/\n\\\\]*\\(\\\\.[^/\n\\\\]*\\)*\\(/\\)"
            (4 "\"/")