From: dblack@...
Date: 2002-12-16T02:07:51+09:00
Subject: Re: un-extending objects

Hi --

On Mon, 16 Dec 2002, ts wrote:

>  Not tested
>
>    class Object
>       def stretch(mod)
>          c = dup
>          c.extend(mod)
>          yield(c)
>       end
>    end

I thought about dup, and avoided it partly because it always seems to
raise issues about deep/shallow copy as well as just being
(potentially) expensive.  In this case, also, the resulting semantics
have a different feel:

  obj.stretch(mod) {|o| o.blah ... }

rather than:

  obj.stretch(mod) { obj.blah ... }

The first one, to me, doesn't convey the sense that this object is
being stretch'ed.  And I think it would behave differently if, say,
there were multiple references to the object, and you expected all
references to be stretched.

Picking up on the block param thing, though: in the non-dup version,
perhaps 'yield self' would be a good idea, so one could chain them:

  arr.stretch(ArrayExtras) {
    arr.to_hash.stretch(HashExtras) { |h| p h.some_new_thing... }
  }

(Getting *very* hypothetical here :-)

Qu'est-ce qu'on y pense?


David

-- 
David Alan Black
home: dblack@candle.superlink.net
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav