From: Jim Freeze <jim@...>
Date: 2005-09-28T03:10:39+09:00
Subject: Re: Class and Iterator Design Question

On 9/27/05, David A. Black <dblack@wobblini.net> wrote:

> I think if you're using pod/peas as a container/elements example, then
> you should accept that the container contains the elements :-)
>
>    pod.each {|pea| ... }
>
> has enough pod/pea semantics to make it clear.  In fact, this:
>
>    pod.each_pea {|pea| ... }
>
> seems a bit redundant to me.  (Unless there's something else that a
> pod might iterate over, similar to String#each vs. String#each_byte.
> Of course, lots of people wish that String#each did what
> String#each_byte does :-)

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.
Here are four methods that I can see as potential solutions:

  1. obj.each(:container) { |element| ... }
  2. obj.each_container { |element| ... }
  3. obj.container.each { |element| ... }
  4. obj.container; obj.each { |element| ... }

No. (4) simply sets an internal state variable to indicate which container
#each uses. Not pretty, and not thread safe, but permits Enumerable to
be used.

Do you have a preference for 1-4 or another solution?

--
Jim Freeze