Subject: bug#10786: 24.0.93; ruby-mode improperly handles symbols with keyword names in JS-style hashes

From: Dmitry Gutov <[email-masked]>
Date: Sat, 11 Feb 2012 04:27:33 +0400

Ruby 1.9 introduced the new syntax for hashes:

{key1: value1, key2: value2}

which is synonymous to {:key1 => value1, :key2 => value2}

The latest ruby-mode highlights the keywords in the new-style hashes 
properly, but fails to account for the case when the symbol's name is an 
otherwise reserved keyword. Examples:

link_to("root", root_path, class: "pink")

before_filter :do_stuff, if: :not_busy?

announce("The end is near!", end: "2012-12-31")

In all examples, the symbol (class, if, end) is being highlighted as a 
reserved keyword, and the indentation becomes broken on all lines below it.

There's a similar bug on the Ruby bug tracker:
http://bugs.ruby-lang.org/issues/5140

See attachment for the patch.

diff --git a/lisp/progmodes/ruby-mode.el b/lisp/progmodes/ruby-mode.el
index a0a6509..8818911 100644
--- a/lisp/progmodes/ruby-mode.el
+++ b/lisp/progmodes/ruby-mode.el
@@ -96,7 +96,7 @@
   (regexp-opt (append ruby-modifier-beg-keywords ruby-block-op-keywords))
   "Regexp to match hanging block modifiers.")
 
-(defconst ruby-block-end-re "\\<end\\>")
+(defconst ruby-block-end-re "\\_<end\\_>")
 
 (eval-and-compile
   (defconst ruby-here-doc-beg-re
@@ -115,9 +115,9 @@ This should only be called after matching against `ruby-here-doc-beg-re'."
                (match-string 6)))))
 
 (defconst ruby-delimiter
-  (concat "[?$/%(){}#\"'`.:]\\|<<\\|\\[\\|\\]\\|\\<\\("
+  (concat "[?$/%(){}#\"'`.:]\\|<<\\|\\[\\|\\]\\|\\_<\\("
           ruby-block-beg-re
-          "\\)\\>\\|" ruby-block-end-re
+          "\\)\\_>\\|" ruby-block-end-re
           "\\|^=begin\\|" ruby-here-doc-beg-re))
 
 (defconst ruby-negative
@@ -166,6 +166,7 @@ This should only be called after matching against `ruby-here-doc-beg-re'."
     (modify-syntax-entry ?$ "." table)
     (modify-syntax-entry ?? "_" table)
     (modify-syntax-entry ?_ "_" table)
+    (modify-syntax-entry ?: "_" table)
     (modify-syntax-entry ?< "." table)
     (modify-syntax-entry ?> "." table)
     (modify-syntax-entry ?& "." table)
@@ -565,7 +566,7 @@ and `\\' when preceded by `?'."
               (setq nest (cons (cons nil pnt) nest))
               (setq depth (1+ depth))))
         (goto-char (match-end 0)))
-       ((looking-at (concat "\\<\\(" ruby-block-beg-re "\\)\\>"))
+       ((looking-at (concat "\\_<\\(" ruby-block-beg-re "\\)\\_>"))
         (and
          (save-match-data
            (or (not (looking-at (concat "do" ruby-keyword-end-re)))
@@ -864,7 +865,7 @@ move backward."
   ;; It seems like it should move to the line where indentation should deepen,
   ;; but ruby-indent-beg-re only accounts for whitespace before class, module and def,
   ;; so this will only match other block beginners at the beginning of the line.
-  (and (re-search-backward (concat "^\\(" ruby-indent-beg-re "\\)\\b") nil 'move)
+  (and (re-search-backward (concat "^\\(" ruby-indent-beg-re "\\)\\_>") nil 'move)
        (beginning-of-line)))
 
 (defun ruby-move-to-block (n)