rename meta to singleton class

seems more appropriate, as it is the class for a single object
Also seems to be called that on the net (don't remember where the meta came from, but it's gone)

lib/parfait/singleton_class.rb

@@ -0,0 +1,63 @@
+#
+# In many respects a SingletonClass is like a Class. We haven't gone to the full ruby/oo level
+# yet, where the singleton_class is actually a class instance, but someday.
+
+# A Class in general can be viewed as a way to generate methods for a group of objects.
+
+# A SingletonClass serves the same function, but just for one object, the class object that it
+# is the singleton_class of.
+# This is slightly different in the way that the type of the class must actually
+# change, whereas for a class the instance type changes and only objects generated
+# henceafter have a different type.
+
+# Another current difference is that a singleton_class has no superclass. Also no name.
+# There is a one to one relationship between a class instance and it's singleton_class instance.
+
+module Parfait
+  class SingletonClass < Behaviour
+
+    attr_reader :clazz
+
+    def self.type_length
+      4
+    end
+    def self.memory_size
+      8
+    end
+
+    def initialize( clazz , clazz_type)
+      raise "No type for #{clazz.name}" unless clazz_type
+      super( clazz_type )
+      @clazz = clazz
+    end
+
+    def rxf_reference_name
+      @clazz.name
+    end
+
+    def inspect
+      "SingletonClass(#{@clazz.name})"
+    end
+
+    def to_s
+      inspect
+    end
+
+    # adding an instance changes the instance_type to include that variable
+    def add_instance_variable( name , type)
+      super(name,type)
+      @clazz.set_type(@instance_type)
+    end
+
+    # Nil name means no superclass, and so nil returned
+    def super_class
+      return nil
+    end
+
+    # no superclass, return nil to signal
+    def super_class_name
+      nil
+    end
+
+  end
+end