From: Kristof Bastiaensen <kristof@...>
Date: 2005-05-22T18:45:16+09:00
Subject: Re: join not in Enumerable

On Sun, 22 May 2005 11:05:10 +0900, David A. Black wrote:
 
>> Why is join, and perhaps even pack in Array and not in Enumerable?
> 
> I guess to_a makes the conversion pretty easy, and Array tends to
> serve as the "normalized" version of Enumerable in a lot of contexts.
> I don't know if there's any other reason.

I believe because join requires an ordered collection, and enumerables
aren't guaranteed to be ordered.  For example the order of traversing a
Hash may differ for a different hash with the same elements.  For this
reason the output of join for an enumerable is undefined.

Regards,
KB