From: polypus <polypus@...>
Date: 2006-05-04T06:36:08+09:00
Subject: klass.include vs instance.extend question


i want a few instance methods to be automatically defined for the user 
without any explicit coding on their part.

in the below distillation of my code, i have two options (labelled), my 
question
is whether one option is better in any way than the other, and why one 
would prefer one over the other. my suspicion is that option 1 is more 
space efficient, and option 2 more time efficient, is that correct?

also i should note that for people to use my module M they must call 
(for other reasons) extend, foo, and init_m in the extended class 
regardless of which option i finally choose. also the method init_m must 
be defined in the manner below (define_method) regardless of the option 
i choose, also for other reasons. and so you should not take any of 
their having to be there or not into account in your assesment. thanks 
many.

module InstanceMethods
  # instance methods in here
end

module M
  # option 1
  def self.extend_object klass
    klass.class_eval 'include InstanceMethods'
    super
  end
  # option 2
  def foo
    define_method :init_m do
      self.extend InstanceMethods
    end
  end

end

class X
  extend M
  foo
  def intialize
    init_m
  end
end


-- 
Posted via http://www.ruby-forum.com/.