gistfile1.diff

diff --git a/lib/kpeg/code_generator.rb b/lib/kpeg/code_generator.rb
index 55376d6..bcdddcd 100644
--- a/lib/kpeg/code_generator.rb
+++ b/lib/kpeg/code_generator.rb
@@ -263,7 +263,11 @@ module KPeg
         code << indentify("_tmp = _tmp ? nil : true\n", indent)
         code << indentify("self.pos = #{ss}\n", indent)
       when RuleReference
-        code << indentify("_tmp = apply(:#{method_name op.rule_name})\n", indent)
+        if op.arguments
+          code << indentify("_tmp = apply(:#{method_name op.rule_name}, #{op.arguments[1..-2]})\n", indent)
+        else
+          code << indentify("_tmp = apply(:#{method_name op.rule_name})\n", indent)
+        end
       when InvokeRule
         if op.arguments
           code << indentify("_tmp = #{method_name op.rule_name}#{op.arguments}\n", indent)
diff --git a/lib/kpeg/compiled_parser.rb b/lib/kpeg/compiled_parser.rb
index 01acada..115770d 100644
--- a/lib/kpeg/compiled_parser.rb
+++ b/lib/kpeg/compiled_parser.rb
@@ -229,8 +229,9 @@ module KPeg
       end
     end
 
-    def apply(rule)
-      if m = @memoizations[rule][@pos]
+    def apply(rule, *args)
+      k = args.empty? ? rule : [rule, *args]
+      if m = @memoizations[k][@pos]
         m.inc!
 
         prev = @pos
@@ -246,17 +247,17 @@ module KPeg
       else
         lr = LeftRecursive.new(false)
         m = MemoEntry.new(lr, @pos)
-        @memoizations[rule][@pos] = m
+        @memoizations[k][@pos] = m
         start_pos = @pos
 
-        ans = __send__ rule
+        ans = __send__ rule, *args
 
         m.move! ans, @pos, @result
 
         # Don't bother trying to grow the left recursion
         # if it's failing straight away (thus there is no seed)
         if ans and lr.detected
-          return grow_lr(rule, start_pos, m)
+          return grow_lr(rule, args, start_pos, m)
         else
           return ans
         end
@@ -265,12 +266,12 @@ module KPeg
       end
     end
 
-    def grow_lr(rule, start_pos, m)
+    def grow_lr(rule, args, start_pos, m)
       while true
         @pos = start_pos
         @result = m.result
 
-        ans = __send__ rule
+        ans = __send__ rule, *args
         return nil unless ans
 
         break if @pos <= m.pos
diff --git a/lib/kpeg/format.kpeg b/lib/kpeg/format.kpeg
index bf017d1..611e638 100644
--- a/lib/kpeg/format.kpeg
+++ b/lib/kpeg/format.kpeg
@@ -81,13 +81,14 @@ sgl_escape_quote = "\\'" { "'" }
                  | "~" method:m < nested_paren? >
                    { @g.action("#{m}#{text}") }
                  | "." { @g.dot }
-                 | "@" var:name !(- "=") { @g.invoke(name) }
+                 | "@" var:name < nested_paren? > !(- "=")
+                   { @g.invoke(name, text.empty? ? nil : text) }
                  | "^" var:name < nested_paren? >
                    { @g.foreign_invoke("parent", name, text) }
                  | "%" var:gram "." var:name < nested_paren? >
                    { @g.foreign_invoke(gram, name, text) }
                  | var:name < nested_paren? > !(- "=")
-                   { text.empty? ? @g.ref(name) : @g.invoke(name, text) }
+                   { @g.ref(name, nil, text.empty? ? nil : text) }
                  | char_range
                  | regexp
                  | string
diff --git a/lib/kpeg/grammar.rb b/lib/kpeg/grammar.rb
index 40e4107..0a8185b 100644
--- a/lib/kpeg/grammar.rb
+++ b/lib/kpeg/grammar.rb
@@ -396,13 +396,14 @@ module KPeg
   end
 
   class RuleReference < Operator
-    def initialize(name, grammar=nil)
+    def initialize(name, grammar=nil, args=nil)
       super()
       @rule_name = name
       @grammar = grammar
+      @arguments = args
     end
 
-    attr_reader :rule_name
+    attr_reader :rule_name, :arguments
 
     def match(x)
       if @grammar and @grammar != x.grammar
@@ -421,14 +422,19 @@ module KPeg
     def ==(obj)
       case obj
       when RuleReference
-        @rule_name == obj.rule_name
+        @rule_name == obj.rule_name and @arguments == obj.arguments
       else
         super
       end
     end
 
     def inspect
-      inspect_type "ref", @rule_name
+      if @arguments
+        body = "#{@rule_name} #{@arguments}"
+      else
+        body = @rule_name
+      end
+      inspect_type "ref", body
     end
   end
 
@@ -807,8 +813,8 @@ module KPeg
       NotPredicate.new Grammar.resolve(node)
     end
 
-    def ref(name, other_grammar=nil)
-      RuleReference.new name.to_s, other_grammar
+    def ref(name, other_grammar=nil, args=nil)
+      RuleReference.new name.to_s, other_grammar, args
     end
 
     def invoke(name, args=nil)
diff --git a/lib/kpeg/grammar_renderer.rb b/lib/kpeg/grammar_renderer.rb
index 9883d1c..de43f06 100644
--- a/lib/kpeg/grammar_renderer.rb
+++ b/lib/kpeg/grammar_renderer.rb
@@ -132,11 +132,15 @@ module KPeg
           render_op io, op.op
         end
       when RuleReference
-        io.print op.rule_name
-      when InvokeRule
         if op.arguments
           io.print "#{op.rule_name}#{op.arguments}"
         else
+          io.print "#{op.rule_name}"
+        end
+      when InvokeRule
+        if op.arguments
+          io.print "@#{op.rule_name}#{op.arguments}"
+        else
           io.print "@#{op.rule_name}"
         end
       when ForeignInvokeRule