create rubyx dir and move previous vool_compiler there

lib/vool/variables.rb

@@ -0,0 +1,41 @@
+module Vool
+  module Named
+    attr_reader :name
+    def initialize name
+      @name = name
+    end
+    def each(&block)
+    end
+  end
+
+  class LocalVariable < Expression
+    include Named
+    def slot_definition(method)
+      if method.arguments_type.variable_index(@name)
+        type = :arguments
+      else
+        type = :frame
+      end
+      Mom::SlotDefinition.new(:message , [type , @name])
+    end
+  end
+
+  class InstanceVariable < Expression
+    include Named
+    def slot_definition(method)
+      Mom::SlotDefinition.new(:message , [ :receiver , @name] )
+    end
+    # used to collect type information
+    def add_ivar( array )
+      array << @name
+    end
+  end
+
+  class ClassVariable < Expression
+    include Named
+  end
+
+  class ModuleName < Expression
+    include Named
+  end
+end