From: why the lucky stiff <ruby-talk@...>
Date: 2004-04-24T05:02:48+09:00
Subject: Re: StringIO

Hal Fulton wrote:

> I've been playing with StringIO, and I've found that it doesn't inherit
> from IO.
>
> I had thought this would be natural, as it would in theory permit us to
> use a StringIO wherever an IO is used.

I don't know exactly what you're getting at, but, in watching checkins 
on Ruby CVS, anything that read:

   if obj.is_a? IO

was swapped to:

  if obj.respond_to? :read

over the last year.  I'm not saying StringIO shouldn't inherit from IO.  
Just that it's become less important what descends from IO and more 
important what implements obj#read.

_why