Splitting NameExpression into three, Known,Local,Argument

The decision which to use can be made higher up, in ruby, and so it
should.

lib/melon/compilers/method_compiler.rb

@@ -14,7 +14,7 @@ module Melon
       def on_ivasgn(statement)
         name , value = *statement
         w = Vm::Tree::Assignment.new()
-        w.name = Vm::Tree::NameExpression.new( name[1..-1].to_sym)
+        w.name = Vm::Tree::InstanceName.new( name[1..-1].to_sym)
         w.value = process(value)
         w
       end
@@ -22,8 +22,8 @@ module Melon
       def on_ivar( var )
         name = var.children.first
         w = Vm::Tree::FieldAccess.new()
-        w.receiver = Vm::Tree::NameExpression.new(:self)
-        w.field = Vm::Tree::NameExpression.new( name[1..-1].to_sym)
+        w.receiver = Vm::Tree::KnownName.new(:self)
+        w.field = Vm::Tree::InstanceName.new( name[1..-1].to_sym)
         w
       end
 
@@ -31,12 +31,20 @@ module Melon
         receiver , name , args = *statement
         w = Vm::Tree::CallSite.new()
         puts "receiver #{statement}"
-        w.name = process(receiver)
+        w.name = name
         w.arguments = process(args)
-        w.receiver = nil
+        w.receiver = process(receiver)
         w
       end
 
+      def on_lvar(statement)
+        name = statement.children.first.to_sym
+        if(@ruby_method.args_type.variable_index(name))
+          return Vm::Tree::ArgumentName.new(name)
+        end
+        raise "Not found #{name}"
+      end
+
       def on_str( string )
         Vm::Tree::StringExpression.new(string.children.first)
       end