From: Trans <transfire@...>
Date: 2005-03-25T00:29:49+09:00
Subject: Re: RCR 296: Destructive methods return self


Matt Maycock wrote:
> > Yet that doesn't seem at all useful for non-destructive methods.
> > "obj->strip" would be pointless, I think. It would be more useful
if
> > any method could act destructively. As I suggested earlier:
"obj!sort".
> > Perhaps a better notation for this  would be your suggestion
> > "obj->sort". But this is all quite speculative given that matz has
> > never seemed too keen in pursing generalized in-place modification.
>
> But it is useful if you are not self-destructive (ie, you are still
> doing side effects, but effecting the world instead of just self).

Ah, fair point.

> Matz may be against generalized in-place modifications (so am I - I'm
> a haskell kid at heart), but it does get used.  When efficiency is
> needed, fp is dropped for scripting, and then for more efficient
> scripting, and then for C.  But what I'm suggesting has nothing to do
> with in place scripting, but is really just a sort of with statement,
> but I think rather more elegant than the kind that comes with VB, and
> is syntactically pleasant.

Right, I realize. Just seemded to me that a "with" statement is
primarily useful with in-place methods. So I thought to take your
suggestion all the way to that point. But you are right, there is a
potential use without destructive methods, albiet less common.

> I think that without a stricter type system, having the interpretter
> make good use of turning a invocation into a modification might be
> harder than you think (maybe even in general impossible - but good
> enough in practice)  - leaving the details up to us at this
particular
> level might be a good idea.

Yes, I imagine you are right. I am an unclear as to exactly how this
works. I know some have done such a thing (evil.rb for instance). But I
have also heared the phrase "segmentation fault" in reference to such
things too. There must be complications that I am unaware-of.

T.