From: ara.t.howard@...
Date: 2006-07-27T00:51:34+09:00
Subject: Re: Set an instance variable before and after initialize

On Wed, 26 Jul 2006, Ben Nagy wrote:

> Oh, I did that too. My point is that there is no 'before' and 'after' the
> code gets run at the same time and it's not possible to insert other code in
> between them, which was presumably the point?


hmmm.  you can actually do it with my first impl by including the module
__after__ defining initialize.  but this makes it easier:


     harp:~ > cat a.rb
     module BeforeAfterInit
       module InstanceMethods
         def before_initialize(*a, &b) end
         def after_initialize(*a, &b) end
       end
       module ClassMethods
         def before &b
           define_method 'before_initialize', &b
           private 'before_initialize'
         end
         def after &b
           define_method 'after_initialize', &b
           private 'after_initialize'
         end
         def new(*a, &b)
           (obj = allocate).instance_eval{
             before_initialize
             initialize *a, &b
             after_initialize
             self
           }
         end
       end
       def self.included other
         other.module_eval{ include InstanceMethods }
         other.extend ClassMethods
         super
       end
     end

     class C < ::Array
       include BeforeAfterInit

       before{ self << :before }
       after{ self << :after }

       def initialize
         self << :initialize
       end
     end

     p C.new


     harp:~ > ruby a.rb
     [:before, :initialize, :after]


regards.


-a
-- 
suffering increases your inner strength.  also, the wishing for suffering
makes the suffering disappear.
- h.h. the 14th dali lama