From: Florian Frank <flori@...>
Date: 2005-09-28T19:10:28+09:00
Subject: Re: Class and Iterator Design Question

Jim Freeze wrote:
> Ok, so you convinced me. Use #each. But, there still does not seem
> to be a clear answer for an object having multiple containers.
> Granted, there is precedence with things like #each_byte. But,
> I wonder if it is better to use an argument to each.

I think people should require 'enumerator' for this, it creates 
Kernel#enum_for, so you can create a Enumerable::Enumerator instance
for every iterator:

somethings = obj.enum_for(:each_something)

Then you can iterate

somethings.each do |something|
   # ...
end

and because Enumerator includes Enumerable, you can get an
array as well by calling

somethings_array = somethings.to_a

without breaking encapsulation.

This solves all your problems, and you only have to create an arbitrary 
named iterator method. I think enumerator should become part of Standard 
Ruby, because it's so damn useful.