Dynamically defining class method

There is this concept of metaclass in ruby. If we wanna dynamically define a class method, we need to play with metaclass:

1 2 3 4 5 6 7 8 9 10 11 12

class Human def self.say_hello puts %\class says 'hello'\ end end message = 'hello world' meta_klass = (class << Human ; self ; end) meta_klass.send(:define_method, :say_hello) { puts %\class says '#{message}'\ } Human.say_hello # >> class says 'hello world'