>From ac047bcebe08a8f850e3a3400156316088fd9520 Mon Sep 17 00:00:00 2001
From: Dmitry Gutov <dgutov@yandex.ru>
Date: Sat, 28 Apr 2012 22:11:00 +0400
Subject: [PATCH 2/2] * lisp/progmodes/ruby-mode.el: Go back to method
 whitelisting for regexps.
 ruby-syntax-methods-before-regexp: New variable.
 (ruby-syntax-propertize-function): Use it to recognize
 regexps. Don't look at the text after regexp, just use
 the old approach.

* test/indent/ruby.rb: Update examples, add a new one.
---
 lisp/progmodes/ruby-mode.el |   38 ++++++++++++++++++++------------------
 test/indent/ruby.rb         |   25 +++++++++++++------------
 2 files changed, 33 insertions(+), 30 deletions(-)

diff --git a/lisp/progmodes/ruby-mode.el b/lisp/progmodes/ruby-mode.el
index 432680f..14ce846 100644
--- a/lisp/progmodes/ruby-mode.el
+++ b/lisp/progmodes/ruby-mode.el
@@ -226,6 +226,13 @@ Also ignores spaces after parenthesis when 'space."
   "Use `ruby-encoding-map' to set encoding magic comment if this is non-nil."
   :type 'boolean :group 'ruby)
 
+(defcustom ruby-syntax-methods-before-regexp
+  '("gsub" "gsub!" "sub" "sub!" "scan" "split" "split!" "index" "match"
+    "assert_match" "Given" "Then" "When")
+  "Methods that can take regexp as the first argument.
+It will be properly highlighted even when the call omits parens."
+  :group 'ruby)
+
 ;; Safe file variables
 (put 'ruby-indent-tabs-mode 'safe-local-variable 'booleanp)
 (put 'ruby-indent-level 'safe-local-variable 'integerp)
@@ -1137,28 +1144,23 @@ See `add-log-current-defun-function'."
                         ;; Not within a string.
                         (nth 3 (syntax-ppss (match-beginning 0))))
                 (string-to-syntax "\\"))))
-          ;; Regexps: regexps are distinguished from division either because
-          ;; of the keyword/symbol before them, or because of the code
-          ;; following them.
+          ;; Regexps: regexps are distinguished from division because
+          ;; of the keyword, symbol, or method name before them.
           ((concat
             ;; Special tokens that can't be followed by a division operator.
-            "\\(?:\\(^\\|[[=(,~?:;<>]\\|\\(?:^\\|\\s \\)"
+            "\\(^\\|[[=(,~?:;<>]"
+            ;; Control flow keywords and operators following bol or whitespace.
+            "\\|\\(?:^\\|\\s \\)"
             (regexp-opt '("if" "elsif" "unless" "while" "until" "when" "and"
-                          "or" "&&" "||"
-                          "gsub" "gsub!" "sub" "sub!" "scan" "split" "split!"))
-            "\\)\\s *\\)?"
+                          "or" "not" "&&" "||"))
+            ;; Method name from the list.
+            "\\|\\_<"
+            (regexp-opt ruby-syntax-methods-before-regexp)
+            "\\)\\s *"
             ;; The regular expression itself.
-            "\\(/\\)[^/\n\\\\]*\\(?:\\\\.[^/\n\\\\]*\\)*\\(/\\)"
-            ;; Special code that cannot follow a division operator.
-            ;; FIXME: Just because the second slash of "/foo/ do bar" can't
-            ;; be a division, doesn't mean it can't *start* a regexp, as in
-            ;; "x = toto/foo; if /do bar/".
-            "\\([imxo]*\\s *\\(?:,\\|\\_<do\\_>\\)\\)?")
-           (2 (when (or (match-beginning 1) (match-beginning 4))
-                (string-to-syntax "\"/")))
-           (3 (if (or (match-beginning 1) (match-beginning 4))
-                  (string-to-syntax "\"/")
-                (goto-char (match-end 2)))))
+            "\\(/\\)[^/\n\\\\]*\\(?:\\\\.[^/\n\\\\]*\\)*\\(/\\)")
+           (2 (string-to-syntax "\"/"))
+           (3 (string-to-syntax "\"/")))
           ("^=en\\(d\\)\\_>" (1 "!"))
           ("^\\(=\\)begin\\_>" (1 "!"))
           ;; Handle here documents.
diff --git a/test/indent/ruby.rb b/test/indent/ruby.rb
index 7a9d123..4f2e9e6 100644
--- a/test/indent/ruby.rb
+++ b/test/indent/ruby.rb
@@ -1,24 +1,25 @@
-# Don't mis-match "sub" at the end of words.
-a = asub / aslb + bsub / bslb;
-
+# Percent literals.
 b = %Q{This is a "string"}
-c = %w(foo
+c = %w!foo
  bar
- baz)
-d = %!hello!
+ baz!
+d = %(hello (nested) world)
 
 # Don't propertize percent literals inside strings.
 "(%s, %s)" % [123, 456]
 
-# Nor inside comments.
+# Or inside comments.
 x = # "tot %q/to"; =
 y = 2 / 3
 
-# A "do" after a slash means that slash is not a division, but it doesn't imply
-# it's a regexp-ender, since it can be a regexp-starter instead!
-x = toto / foo; if /do bar/ then
-                  toto = 1
-                end
+# Regexp after whitelisted method.
+"abc".sub /b/, 'd'
+
+# Don't mis-match "sub" at the end of words.
+a = asub / aslb + bsub / bslb;
+
+# Highlight the regexp after "if".
+x = toto / foo if /do bar/ =~ "dobar"
 
 # Some Cucumber code:
 Given /toto/ do
-- 
1.7.10.msysgit.1