From: Devin Mullins <twifkak@...>
Date: 2005-09-27T06:05:01+09:00
Subject: Re: How each class splats

Robert Klemme wrote:

>Devin Mullins wrote:
>  
>
>>But I think your best bet is define your own Collection object with
>>its own #each.
>>    
>>
>I though so, too, but it doesn't help:
><snip>
>  
>
Oooh... not what I meant. :) I meant something like this:

class B
  attr_reader :i, :v
  def initialize(i,v)
    @i, @v = i, v
  end
end

class ArrayOfB < DelegateClass(Array)
  def each
    super { |b| yield b.i, b.v }
  end
end

a = ArrayOfB.new [B.new(:a, 1), B.new(:b, 2)]
a.each { |i, v| puts "i = #{i.inspect}, v = #{v.inspect}" }

>In other words, it's not sufficient to be Enumerable to automatically be
>assigned to individual variables in this scenario.  You must have an
>Array.  Maybe to change this is worth an RCR?
>  
>
Definitely not .include? Enumerable, since not all Enumerable methods 
require finity (finiteness? finition? finality?)*. Maybe against .to_a, 
though, but its deprecatedness (deprecatedity? deprecatality? 
deprecation? aha! deprecation!) on Object makes me wonder if we aren't 
heading down a path matz & friends already scoped out and nixed..

>While I would find this convenient it's really not too hard to access
>members explicitely.
>  
>
Ditto.

Devin.

*Point in case:

class Fibs
  extend Enumerable
  def self.each
    i, j = 0, 1
    loop do
      yield i
      i, j = j, i + j
    end
  end
end

#find the first Fibonacci number with two nines in a row
Fibs.find { |i| i.to_s =~ /99/ }