* lisp/progmodes/ruby-mode.el

(ruby-syntax-propertize-function): After everything else, search
for expansions in string literals, mark their insides as
whitespace syntax and save match data for font-lock.
(ruby-font-lock-keywords): Highlight just the 2nd group from
expression expansion matches.
(ruby-match-expression-expansion): Use the match data saved to the
text property in ruby-syntax-propertize-function.

* test/automated/ruby-mode-tests.el
Change direct font-lock face references to var references.
(ruby-interpolation-suppresses-syntax-inside): New test.
(ruby-interpolation-inside-percent-literal-with-paren): New
failing test.

4 files changed, 62 insertions, 13 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 19623bd06b7..99bfabb8115 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -2,6 +2,15 @@
 
         * progmodes/ruby-mode.el (ruby-expr-beg): Make heredoc detection
         more strict.  Add docstring.
+        (ruby-expression-expansion-re): Extract from
+        `ruby-match-expression-expansion'.
+        (ruby-syntax-propertize-function): After everything else, search
+        for expansions in string literals, mark their insides as
+        whitespace syntax and save match data for font-lock.
+        (ruby-font-lock-keywords): Use the 2nd group from expression
+        expansion matches.
+        (ruby-match-expression-expansion): Use the match data saved to the
+        text property in ruby-syntax-propertize-function.
 
 2012-11-14  Stefan Monnier  <monnier@iro.umontreal.ca>
 
diff --git a/lisp/progmodes/ruby-mode.el b/lisp/progmodes/ruby-mode.el
index 686bec89a95..9d78b20ba4c 100644
--- a/lisp/progmodes/ruby-mode.el
+++ b/lisp/progmodes/ruby-mode.el
@@ -105,7 +105,10 @@
 (eval-and-compile
   (defconst ruby-here-doc-beg-re
   "\\(<\\)<\\(-\\)?\\(\\([a-zA-Z0-9_]+\\)\\|[\"]\\([^\"]+\\)[\"]\\|[']\\([^']+\\)[']\\)"
-    "Regexp to match the beginning of a heredoc."))
+  "Regexp to match the beginning of a heredoc.")
+
+  (defconst ruby-expression-expansion-re
+    "[^\\]\\(\\\\\\\\\\)*\\(#\\({[^}\n\\\\]*\\(\\\\.[^}\n\\\\]*\\)*}\\|\\(\\$\\|@\\|@@\\)\\(\\w\\|_\\)+\\)\\)"))
 
 (defun ruby-here-doc-end-match ()
   "Return a regexp to find the end of a heredoc.
@@ -1249,7 +1252,19 @@ It will be properly highlighted even when the call omits parens."))
           ;; Handle percent literals: %w(), %q{}, etc.
           ((concat "\\(?:^\\|[[ \t\n<+(,=]\\)" ruby-percent-literal-beg-re)
            (1 (prog1 "|" (ruby-syntax-propertize-percent-literal end)))))
-         (point) end))
+         (point) end)
+        (remove-text-properties start end '(ruby-expansion-match-data))
+        (goto-char start)
+        ;; Find all expression expansions and
+        ;; - set the syntax of all text inside to whitespace,
+        ;; - save the match data to a text property, for font-locking later.
+        (while (re-search-forward ruby-expression-expansion-re end 'move)
+          (when (ruby-in-ppss-context-p 'string)
+            (put-text-property (match-beginning 2) (match-end 2)
+                               'syntax-table (string-to-syntax "-"))
+            (put-text-property (match-beginning 2) (1+ (match-beginning 2))
+                               'ruby-expansion-match-data
+                               (match-data)))))
 
       (defun ruby-syntax-propertize-heredoc (limit)
         (let ((ppss (syntax-ppss))
@@ -1582,7 +1597,7 @@ See `font-lock-syntax-table'.")
    '("\\(^\\s *\\|[\[\{\(,]\\s *\\|\\sw\\s +\\)\\(\\(\\sw\\|_\\)+\\):[^:]" 2 font-lock-constant-face)
    ;; expression expansion
    '(ruby-match-expression-expansion
-     0 font-lock-variable-name-face t)
+     2 font-lock-variable-name-face t)
    ;; warn lower camel case
                                         ;'("\\<[a-z]+[a-z0-9]*[A-Z][A-Za-z0-9]*\\([!?]?\\|\\>\\)"
                                         ;  0 font-lock-warning-face)
@@ -1590,9 +1605,14 @@ See `font-lock-syntax-table'.")
   "Additional expressions to highlight in Ruby mode.")
 
 (defun ruby-match-expression-expansion (limit)
-  (when (re-search-forward "[^\\]\\(\\\\\\\\\\)*\\(#\\({[^}\n\\\\]*\\(\\\\.[^}\n\\\\]*\\)*}\\|\\(\\$\\|@\\|@@\\)\\(\\w\\|_\\)+\\)\\)" limit 'move)
-    (or (ruby-in-ppss-context-p 'string)
-        (ruby-match-expression-expansion limit))))
+  (let ((prop 'ruby-expansion-match-data) pos value)
+    (when (and (setq pos (next-single-char-property-change (point) prop
+                                                           nil limit))
+               (> pos (point)))
+      (goto-char pos)
+      (or (and (setq value (get-text-property pos prop))
+               (progn (set-match-data value) t))
+          (ruby-match-expression-expansion limit)))))
 
 ;;;###autoload
 (define-derived-mode ruby-mode prog-mode "Ruby"
diff --git a/test/ChangeLog b/test/ChangeLog
index 5a796408a3b..f11325d0318 100644
--- a/test/ChangeLog
+++ b/test/ChangeLog
@@ -3,6 +3,10 @@
         * automated/ruby-mode-tests.el (ruby-indent-singleton-class): Pass.
         (ruby-indent-inside-heredoc-after-operator)
         (ruby-indent-inside-heredoc-after-space): New tests.
+        Change direct font-lock face references to var references.
+        (ruby-interpolation-suppresses-syntax-inside): New test.
+        (ruby-interpolation-inside-percent-literal-with-paren): New
+        failing test.
 
 2012-11-13  Dmitry Gutov  <dgutov@yandex.ru>
 
diff --git a/test/automated/ruby-mode-tests.el b/test/automated/ruby-mode-tests.el
index 7d633be0f53..ad48413b030 100644
--- a/test/automated/ruby-mode-tests.el
+++ b/test/automated/ruby-mode-tests.el
@@ -80,7 +80,7 @@ VALUES-PLIST is a list with alternating index and value elements."
 
 (ert-deftest ruby-heredoc-font-lock ()
   (let ((s "foo <<eos.gsub('^ *', '')"))
-    (ruby-assert-face s 9 'font-lock-string-face)
+    (ruby-assert-face s 9 font-lock-string-face)
     (ruby-assert-face s 10 nil)))
 
 (ert-deftest ruby-singleton-class-no-heredoc-font-lock ()
@@ -262,19 +262,35 @@ VALUES-PLIST is a list with alternating index and value elements."
     (should (string= "foo do |b|\n  b + 1\nend" (buffer-string)))))
 
 (ert-deftest ruby-recognize-symbols-starting-with-at-character ()
-  (ruby-assert-face ":@abc" 3 'font-lock-constant-face))
+  (ruby-assert-face ":@abc" 3 font-lock-constant-face))
 
 (ert-deftest ruby-hash-character-not-interpolation ()
   (ruby-assert-face "\"This is #{interpolation}\"" 15
-                    'font-lock-variable-name-face)
+                    font-lock-variable-name-face)
   (ruby-assert-face "\"This is \\#{no interpolation} despite the #\""
-                    15 'font-lock-string-face)
-  (ruby-assert-face "\n#@comment, not ruby code" 5 'font-lock-comment-face)
+                    15 font-lock-string-face)
+  (ruby-assert-face "\n#@comment, not ruby code" 5 font-lock-comment-face)
   (ruby-assert-state "\n#@comment, not ruby code" 4 t)
   (ruby-assert-face "# A comment cannot have #{an interpolation} in it"
-                    30 'font-lock-comment-face)
+                    30 font-lock-comment-face)
   (ruby-assert-face "# #{comment}\n \"#{interpolation}\"" 16
-                    'font-lock-variable-name-face))
+                    font-lock-variable-name-face))
+
+(ert-deftest ruby-interpolation-suppresses-syntax-inside ()
+  (let ((s "\"<ul><li>#{@files.join(\"</li><li>\")}</li></ul>\""))
+    (ruby-assert-state s 8 nil)
+    (ruby-assert-face s 9 font-lock-string-face)
+    (ruby-assert-face s 10 font-lock-variable-name-face)
+    (ruby-assert-face s 41 font-lock-string-face)))
+
+(ert-deftest ruby-interpolation-inside-percent-literal-with-paren ()
+  :expected-result :failed
+  (let ((s "%(^#{\")\"}^)"))
+    (ruby-assert-face s 3 font-lock-string-face)
+    (ruby-assert-face s 4 font-lock-variable-name-face)
+    (ruby-assert-face s 10 font-lock-string-face)
+    ;; It's confused by the closing paren in the middle.
+    (ruby-assert-state s 8 nil)))
 
 (ert-deftest ruby-add-log-current-method-examples ()
   (let ((pairs '(("foo" . "#foo")