> now , i know that i can use "define_method" add a method > dynamic, but i want to know how to add a "static method" > dynamic ? You can do this by using define_method in the context of the singleton class of a class: class << aClass define_method ..... end In Ruby, we prefer to call this a "class method". We don't use the term "static method". gegroet, Erik V. - http://www.erikveen.dds.nl/ ---------------------------------------------------------------- ############################################################## class Foo class << self define_method :one do 1 end end class << self self end.module_eval do define_method :two do 2 end end end ############################################################## class Bar end class << Bar define_method :one do 1 end end class << Bar self end.module_eval do define_method :two do 2 end end ############################################################## p Foo.one p Foo.two p Bar.one p Bar.two ############################################################## ----------------------------------------------------------------