Once

once.rb

# once/once.rb: Written by Tadayoshi Funaba 1998,2000,2002,2006,2008
# $Id: once.rb,v 1.2 2008-11-12 19:58:01+09 tadf Exp $

module Once

  def once(*ids)
    for id in ids
      module_eval <<-"end;"
	alias_method :__#{id.object_id}__, :#{id.to_s}
	def #{id.to_s}(*args, &block)
	  (@__#{id.object_id}__ ||= [__#{id.object_id}__(*args, &block)])[0]
	end

		

      end;
    end
  end

  private :once

  def once_class_method(*ids)
    for id in ids
      module_eval <<-"end;"
	class << self
	  alias_method :__#{id.object_id}__, :#{id.to_s}
	  def #{id.to_s}(*args, &block)
	    (@__#{id.object_id}__ ||= [__#{id.object_id}__(*args, &block)])[0]
	  end
	end
      end;
    end
  end

  private :once_class_method

end