From: Daniel DeLorme <dan-ml@...42.com>
Date: 2007-11-13T19:39:36+09:00
Subject: Re: Yielding an object and caring about the result: the cousin of Object#tap

furtive.clown@gmail.com wrote:
> I am a lone rubyist who went off the grid several years ago after
> contributing a project on rubyforge, so perhaps *my* style is the
> quirky one.  Still, in my mind the latter is sheer elegance compared
> to the former.  I actually find it interesting that someone could
> possibly disagree.  Do (1)-(3) make any sense, then?

This kind of suggestion has been made several times in the past and, 
while I agree it looks elegant, I believe the issue is that "as" does 
not really /belong/ to the object on which it is called. It is a utility 
method. If you look at the base methods of Object you'll see that all of 
them have to do with the state of the object itself (except for the ugly 
exception of "display"). Semantically, a utility method has no business 
being part of the public interface of every object. A better solution 
would be with(expr){ |var| ... but that kills the elegance doesn't it? I 
sympathize, I really do. I have the same issue with my pet method "ergo"

Lately I've been thinking that this could tie into Ara's concept of 
"pervasive" methods. If we define a pervasive method as a method that 
applies to all objects, then we could do something like
     Pervasives.define do
       def as
         yield(self)
       end
     end
Which could be called reliably as:
     Pervasives.call(expr, :as){ |obj| ... }
or less reliably through method_missing:
     expr.as{ |obj| ... }
leaving the Object methodspace unpolluted:
     expr.methods.include?("as") #=> false

no?

Daniel