Given an arbitary metaclass, return the object of which the given metaclass is a metaclass

gistfile1.rb

class Fixnum
	def to_fixnum
		self
	end
end

class Bignum
	def to_fixnum
		self[Fixnum::BITS] == 1 ? ~(~(self) & Fixnum::MAX) : self & Fixnum::MAX
	end
end

class Object
	def metaclass
		class << self; self; end
	end
end

class Module
	def const_get_full(name)
		first, rest = name.to_s.split(/::/, 2)
		rest ? const_get(first).const_get_full(rest) : const_get(first)
	end
end

class Class
	def unmetaclass(string = inspect.gsub(/^<\#Class:(.*)>$/, '\1'), recur = 0)
		begin
			Object.const_get_full(string)
		rescue NameError
			string.gsub!(/^\#<(?:[A-Z](?:[A-Za-z_]*)(?:::)?)+:(.*)>$/, '\1')
			if string =~ /^0x[a-f0-9]+$/
				ObjectSpace._id2ref((string.to_i(16) / 2).to_fixnum)
			else
				object = unmetaclass(string, recur + 1)
				recur > 0 ? object.metaclass : object
			end
		end
	end
end