From: Martin DeMello <martindemello@...>
Date: 2003-12-29T17:56:48+09:00
Subject: Re: Inconsistent value of uninitialized variable

Nathaniel Talbott <nathaniel@talbott.ws> wrote:
> On Dec 28, 2003, at 23:11, Martin DeMello wrote:
> 
> > Nathaniel Talbott <nathaniel@talbott.ws> wrote:
> >> Isn't it this behavior that makes it possible to define a recursive
> >> block?
> >>
> >>    y = 0
> >>    x = proc{y += 1; x.call unless(y == 100); y}
> >>    p x.call
> >>
> >> I suppose you could require a prior assignment to x in this case, but
> >> that starts to smell like having to declare variables...
> >
> > This is not a proper recursive block - for instance
> >
> > y = 0
> > x = proc{y += 1; x.call unless(y == 100); y}
> > z = x
> > x = nil
> > z.call
> 
> "Not proper" might be strong language, but yes, it could definitely be 

Sorry. Actually, you're right - this'll cover nearly every case in which
you'd want the construct, but relying on a variable name makes me
twitchy.

> broken. Do you have a better construct for a recursive block?

No, I remember fighting over it once, but I didn't get anywhere. I'd
like to see some equivalent to letrec in 2.0, personally.

martin