Subject: bug#20026: [PATCH] 24.4; regexp parse miss in ruby-mode

From: Nobuyoshi Nakada <[email-masked]>
Date: Sat, 07 Mar 2015 10:35:36 +0900

ruby-mode misses a regexp just after an open brace ('{') or a vertical
bar ('|').  As the result, `forward-sexp` and regexp highlighting do not
work expectedly (or as a ruby interpreter interprets).

ex.

  tap { /'/ }

This "/'/" should be parsed as an regexp matches a single quote, but the
first operator is parsed as a division operator and the succeeding
single quote is parsed as a beginning of a string.

Same for `{|x| /'/}`.

--- lisp/progmodes/ruby-mode.el	2014-07-06 05:02:55.000000000 +0900
+++ lisp/progmodes/ruby-mode.el	2015-03-06 21:09:46.000000000 +0900
@@ -1777,7 +1777,7 @@
   (defvar ruby-syntax-before-regexp-re
     (concat
      ;; Special tokens that can't be followed by a division operator.
-     "\\(^\\|[[=(,~;<>]"
+     "\\(^\\|[[{|=(,~;<>]"
      ;; Distinguish ternary operator tokens.
      ;; FIXME: They don't really have to be separated with spaces.
      "\\|[?:] "

In GNU Emacs 24.4.1 (x86_64-apple-darwin14.0.0, NS apple-appkit-1343.16)
 of 2014-12-24 on tenten-slave.macports.org
Windowing system distributor `Apple', version 10.3.1344
Configured using:
 `configure --prefix=/opt/local --with-ns --without-x --without-dbus
 CC=/usr/bin/clang 'CFLAGS=-pipe -Os -arch x86_64'
 'LDFLAGS=-L/opt/local/lib -Wl,-headerpad_max_install_names -arch
 x86_64' CPPFLAGS=-I/opt/local/include'

Important settings:
  locale-coding-system: utf-8-hfs

Major mode: Ruby