From: James Edward Gray II <james@...>
Date: 2005-07-07T22:15:54+09:00
Subject: Re: Inheriting Array and slice() behaviour

On Jul 7, 2005, at 2:40 AM, Robert Klemme wrote:

> Yep.  Or do it selectively (what I'd prefer).  This can help:
>
> class Module
>   def delegate(member, method)
>     class_eval "def #{method}(*a,&b) @#{member}.#{method}(*a,&b) end"
>   end
> end
>
>
>>> class Foo
>>>   def initialize() @s = "foo" end
>>>
>>>
> ?>   delegate :s, :size
>
>>> end
>>>
> "def size(*a,&b) @s.size(*a,&b) end"
> => nil
>
>>> Foo.new.size
>>>
> => 3
>
> Btw, IMHO this would be a good addition to delegate.rb.  What do  
> others
> think?

This is what the standard Forwardable library does:

  class Queue
     extend Forwardable

     def initialize
       @q = [ ]    # prepare delegate object
     end

     # setup prefered interface, enq() and deq()...
     def_delegator :@q, :push, :enq
     def_delegator :@q, :shift, :deq

     # support some general Array methods that fit Queues well
     def_delegators :@q, :clear, :first, :push, :shift, :size
   end

   q = Queue.new
   q.enq 1, 2, 3, 4, 5
   q.push 6

   q.shift    # => 1
   while q.size > 0
     puts q.deq
   end

   q.enq "Ruby", "Perl", "Python"
   puts q.first
   q.clear
   puts q.first

Hope that helps.

James Edward Gray II