             start
               = a:"a" &{return a is "a"}
           '''
-          expect(parser.parse "a").to.eql ["a", ""]
+          expect(tryParse parser, "a").to.eql ["a", ""]
         
         test 'can use the |offset| variable to get the current parse position', ->
           parser = PEG.buildParser '''
             start
               = "a" &{return offset is 1}
           '''
-          expect(parser.parse "a").to.eql ["a", ""]
+          expect(tryParse parser, "a").to.eql ["a", ""]
 
         test 'can use the |line| and |column| variables to get the current line and column', ->
           parser = PEG.buildParser '''

          start
            = "a" { return @val }
        '''
        expect(parser.parse "a").to.equal "2"

      suite 'predicates', ->
        test 'semantic not code', ->
          parser = PEG.buildParser '''
            start
              = !{return typeof Array is "undefined"}
          '''
          expect(parser.parse "").to.equal ""

        test 'semantic and code', ->
          parser = PEG.buildParser '''
            start
              = &{return typeof Array isnt "undefined"}
          '''
          expect(parser.parse "").to.equal ""


      suite 'variable use', ->

    suite 'simple CoffeeScript', ->
      test 'action', ->
        parser = PEG.buildParser 'start = "a" { return "#{1+1}" }'
        expect(tryParse parser, "a").to.equal "2"
        
      test 'initializer', ->
        parser = PEG.buildParser '''
