From: Harry Ohlsen <harryo@...>
Date: 2001-11-30T01:14:41+09:00
Subject: [ruby-talk:26921] Re: overload possible?

In article
<Pine.GSO.4.21.0111291556340.10812-100000@godzilla.ce.chalmers.se>,
"Robert Feldt" <feldt@ce.chalmers.se> wrote:


>> I'm not sure what you mean by rewriting it each time.  Surely, if you
>> want specific code for a specific set of arguments, you're going to
>> have to write that code.  Maybe I'm missed what you were getting at.
>> 
> I mean rewrite the method we're overloading (in my solution the
> dispatching method).

Well, you don't need to rewrite it.  All you need to do is add the code
for the new set of argument types.  I guess this would be an issue if
you didn't have the original code, though.

>> > I'm thinking if I want to overload Fixnum#+ because it should have a
>> > special behavior when argument is my new class then I'd have to
>> > revert to an alias-redefine-and-call scheme, right?

I think I see what you're getting at now.  With the mechanism I
suggested, you'd have a problem, because you can't easily just go
and edit the definition of Fixnum#+, so you'd have to do the alias ...
as you say.

That certainly means it's not available in all cases.  However, I didn't
think the person who asked the original question meant that kind of
thing.  I thought they were talking about code they were writing for
themselves.

It would definitely be nice to have something that worked in all cases,
which I think yours would.  However, I'd personally give up that
generality for what I think is a more straightforward style of defining
the methods.  Obviously, that's only for my personal definition of
"more straightforward" :-).

> Yes, but when you want to add and overload dynamically (at different
> time and from different files etc), how do you do it?

Yep.  Agreed.  This is what I hadn't originally thought about, and as
I say, hadn't thought it was required by the original poster.  I agree,
not having that level of dynamic control does mean it doesn't fit in
well with the ruby way of doing things !!

> Anyway you can have it "both" ways by doing it with a directive but
> allowing the final arg to be a block
> 
>   dispatch :overloaded_method, String, proc{|str| ...}
> 
> or something like that.

True.

> Well, maybe we should drop this; I guess this is not important enough to
> warrant too much discussion... ;-)

Agreed.  I'll shut up now :-) !!