adds message get and set instructions

lib/ast/README.md

@@ -51,7 +51,7 @@ Then a new Method receives the message, creates a Frame for local and temporary
 
 The important thing here is that Messages and Frames are normal objects.
 
-Anf interestingly we can partly use ruby to find the method, so in a way it is not just a top down transformation. but 
+And interestingly we can partly use ruby to find the method, so in a way it is not just a top down transformation. but 
 the sending goes back up and then down again.
 
 The Message object is the second parameter to the compile method, the run-time part as it were.

lib/virtual/instruction.rb

@@ -103,12 +103,14 @@ module Virtual
   class ImplicitBranch < Branch
   end
 
-  # A note: future branch conditions include OverflowBranch and other non-c 
+  class MessageGet < Instruction
+    include Named
+  end
   class FrameGet < Instruction
     include Named
   end
 
-  class FrameSend < Instruction
+  class MessageSend < Instruction
     def initialize name , args = [] , nex = nil
       super(nex)
       @name = name.to_sym
@@ -132,6 +134,18 @@ module Virtual
     end
   end
 
+  class MessageSet < Instruction
+    def initialize name , val , nex = nil
+      super(nex)
+      @name = name.to_sym
+      @value = val
+    end
+    attr_reader :name , :value
+    def attributes
+      [:name , :value] + super
+    end
+  end
+
   class LoadSelf < Instruction
     def initialize val , nex = nil
       super(nex)

lib/virtual/message.rb

@@ -36,19 +36,27 @@ module Virtual
     end
     # 
     def compile_get method , name
-      method.add FrameGet.new(name)
+      if method.has_arg(name)
+        method.add MessageGet.new(name)
+      else
+        method.add FrameGet.new(name)
+      end
       method.get_var(name)
     end
 
     def compile_send method , name , me , with = [] 
       method.add Virtual::LoadSelf.new(me)
-      method.add FrameSend.new(name , with )
+      method.add MessageSend.new(name , with )
       Return.new( method.return_type )
     end
 
     def compile_set method , name , val
       method.set_var(name,val)
-      method.add FrameSet.new(name , val )
+      if method.has_arg(name)
+        method.add MessageSet.new(name , val )
+      else
+        method.add FrameSet.new(name , val )
+      end
       method.get_var(name)
     end
   end

lib/virtual/method_definition.rb

@@ -49,6 +49,13 @@ module Virtual
       var
     end
 
+    # determine whether this method has an argument by the name
+    def has_arg name
+      name = name.to_sym
+      var = @args.find {|a| a.name == name }
+      var
+    end
+
     def set_var name , var
       v = has_var name
       if( v )