#! /usr/bin/env ruby
# attr_temporary written by Shin'ya Adzumi
# version: 0.01

require 'dumper'

class Object
	def temporary_variables
		(__temporary_variables).map{|tv| "#{tv.to_s}"} & instance_variables
	end

	def _pre_format
		unless temporary_variables.empty? then
			obj = self.clone
			obj.instance_eval do
				temporary_variables.each do |t|
					remove_instance_variable(t)
				end
			end
			obj
		else
			self
		end
	end

private
	def __temporary_variables
		[]
	end
end

class Module
private
	def attr_temporary(*name)
		name.each do |n|
			unless n.kind_of? Symbol then
				if n.respond_to? :intern then
					n = n.intern
				else
					raise TypeError, "#{n.inspect} is not a symbol"
				end
			end
			unless n.to_s =~ /^@[^@]/ then
				raise TypeError, "#{n.to_s} is not a instance variable"
			end
		end
		old_tvars = module_eval("__temporary_variables")
		unless (old_tvars & name) == name then
			new_tvars = (old_tvars | name).sort
			module_eval("def __temporary_variables; #{new_tvars.inspect}; end; private :__temporary_variables");
		end
	end
end

module Marshal
	alias :_dump :dump
	def dump(obj,*arg)
		MarshalDumper::dump(obj)
	end
	module_function :_dump,:dump
end

if __FILE__ == $0 then
	class Foo
		attr_temporary :@foo
		def initialize
			@foo=1
		end
	end

	class Bar
		def initialize
			@bar = Foo::new
		end
	end

	p Marshal::load(Marshal::dump(Foo::new))
	p Marshal::load(Marshal::dump(Bar::new))
end