From: "David A. Black" <dblack@...>
Date: 2004-04-04T23:04:35+09:00
Subject: Re: deciding between ruby and python

HI --

On Sun, 4 Apr 2004, Dan Doel wrote:

> Ah, yes. Upon going back and reading I had it backwards. Serves me right for
> trying to rely on my memory alone.
> 
> I'm conflicted in my opinions. On the one hand, perhaps it'd be good
> for #join to only use #to_str to convert, since that means objects
> are allowed to be auto-converted, and that would be appropriate for
> duck typing (that is, the object is saying it acts like a string
> through this conversion). Calling #to_s doesn't mean the object is
> "supposed" to be interchangeable with a string.

I think there's a difference between an object acting like a string
and an object saying it acts like a string.  (Does that make any
sense?)  I've always understood #to_str as mainly for cases where an
object is acted upon directly -- like:

  "x" + obj   # obj had better be able to masquerade as a String

rather than a case like #join where, so to speak, the objects (the
array elements) are asked for string representations of themselves,
rather than for themselves-being-Strings.  

That said, I've also never been 100% sure why String#+ couldn't be
more tolerant -- that is, allow objects to present their #to_s
representations, rather than insisting that they either be Strings or
have a #to_str method.  The whole concept of "wanting a String object"
and having a mechanism that makes an object appear that way strikes me
as uncharacteristically classname-centric for Ruby.  Then again,
perhaps there's a certain amount of classname-based things that have
to happen in order to bootstrap the lovely object-centric programming
space we know and love.  


David

-- 
David A. Black
dblack@wobblini.net