From: Robert Klemme <bob.news@...>
Date: 2005-07-07T22:25:47+09:00
Subject: Re: Inheriting Array and slice() behaviour

James Edward Gray II wrote:
> 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

Yuck!  Didn't new this one.  That covers pretty much everything one needs
(apart from Daniel's suggestion).  Thanks for the heads up!

Kind regards

    robert