From: "ara.t.howard" <ara.t.howard@...>
Date: 2008-05-06T23:25:55+09:00
Subject: Re: delegation question, where I want prototype style delegation


On May 6, 2008, at 12:00 AM, Sam Roberts wrote:
> But it has a problem,  it modifies the target object, but I may want
> to create mutiple delegates to the
> target, each with a different set of "views", that behave like the
> target object would if it
> had its #each method redefined.

you can play with this:


cfp:~ > cat a.rb
class Base
   instance_methods.each do |m|
     unless m[%r/^__/]
       old = m
       new = "__#{ old }__"
       new << '?' if new.sub!('?', '')
       new << '!' if new.sub!('!', '')
       alias_method new, old
       undef_method old
     end
   end

   def initialize object
     @object = object
   end

   def method_missing m, *a, &b
     @object.__send__ m, *a, &b
   end

   Delegates = {}

   def / m
     Delegates[m] ||=
       __dup__.__instance_eval__ do
         extend m
         self
       end
   end
end

module Reverse
   def each *a, &b
     reverse.each *a, &b
   end
end

a = Base.new [2,4]

p a.each{}

p (a/Reverse).each{}



cfp:~ > ruby a.rb
[2, 4]
[4, 2]




a @ http://codeforpeople.com/
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