rubyx/lib/parfait/singleton_class.rb
Torsten Rüger d901c6f27c 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)
2019-09-23 20:57:33 +03:00

64 lines
1.6 KiB
Ruby

#
# 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