metaprograming: define_method, define_singleton_method(1.9)

gistfile1.rb

# base on ruby 1.9
# Reference :
# http://stackoverflow.com/questions/185947/ruby-define-method-vs-def
# define_method is a (private) method of the object Class. You are calling it from an instance. There is no instance method called define_method, so it recurses to your method_missing, this time with :define_method (the name of the missing method), and :screech (the sole argument you passed to define_method).
# http://stackoverflow.com/questions/752717/how-do-i-use-define-method-to-create-class-methods
class Base
  def self.meta_instance_method &block
    define_method "ins", block
  end

  def self.meta_class_method &block
    define_singleton_method "cls", block
  end
end

class Child < Base
  meta_instance_method do
    "This is meta_instance_method"
  end

  meta_class_method do
    "This is meta_class_method"
  end

  def method_missing(m)
    self.class.send(:define_method, "missing") do
      "method_missing"
    end
  end
end

puts Child.new.ins
puts Child.cls
puts Child.new.missing