Resolve ${group:/command} style pattern names

These are used by the todo package to include the lower cased
version of the matched capture index in the pattern scope name.

spec/app/text-mate-grammar-spec.coffee

@@ -511,6 +511,20 @@ describe "TextMateGrammar", ->
         expect(tokens[0].value).toBe "forever and ever"
         expect(tokens[0].scopes).toEqual ["source", "text"]
 
+    describe "${capture:/command} style pattern names", ->
+      lines = null
+
+      beforeEach ->
+        atom.activatePackage('ruby-tmbundle', sync: true)
+        atom.activatePackage('todo-tmbundle', sync: true)
+        grammar = syntax.selectGrammar('main.rb')
+        lines = grammar.tokenizeLines "# TODO be nicer"
+
+      it "replaces the number with the capture group and translates the text", ->
+        tokens = lines[0]
+        expect(tokens[2].value).toEqual "TODO"
+        expect(tokens[2].scopes).toEqual ["source.ruby", "comment.line.number-sign.ruby", "storage.type.class.todo"]
+
   describe "language-specific integration tests", ->
     lines = null
 

src/app/text-mate-grammar.coffee

@@ -422,16 +422,29 @@ class Pattern
     else
       [this]
 
+  resolveScopeName: (line, captureIndices) ->
+    resolvedScopeName = @scopeName.replace /\${(\d+):\/(downcase|upcase)}/, (match, index, command) ->
+      capture = captureIndices[parseInt(index)]
+      if capture?
+        replacement = line.substring(capture.start, capture.end)
+        switch command
+          when 'downcase' then replacement.toLowerCase()
+          when 'upcase' then replacement.toUpperCase()
+          else replacement
+      else
+        match
+
+    resolvedScopeName.replace /\$(\d+)/, (match, index) ->
+      capture = captureIndices[parseInt(index)]
+      if capture?
+        line.substring(capture.start, capture.end)
+      else
+        match
+
   handleMatch: (stack, line, captureIndices) ->
     scopes = scopesFromStack(stack)
     if @scopeName and not @popRule
-      patternScope = @scopeName.replace /\$\d+/, (match) ->
-        capture = captureIndices[parseInt(match.substring(1))]
-        if capture?
-          line.substring(capture.start, capture.end)
-        else
-          match
-      scopes.push(patternScope)
+      scopes.push(@resolveScopeName(line, captureIndices))
 
     if @captures
       tokens = @getTokensForCaptureIndices(line, _.clone(captureIndices), scopes, stack)