On Thu, Aug 17, 2006 at 11:45:06PM -0400, Joe Gottman wrote:
> > -----Original Message-----
> > From: Luke Palmer [mailto:[EMAIL PROTECTED]
> > Sent: Thursday, August 17, 2006 8:44 PM
> > To: Perl6 Language List
> >
> > Wasn't NEXT supposed to do something tricky, such as being mutually
> > exclusive with LAST? I remember a debate some time ago where some
> > complained "but that would be hard to implement", and the solution
> > being mostly correct but failing in this case.
> >
> > I seem to recall NEXT being created in order to do things like this:
> >
> > for @objs {
> > .print;
> > NEXT { print ", " }
> > LAST { print "\n" }
> > }
> >
> > We also might consider using perl6's hypothetical features to
> > implement NEXT correctly in all cases (except for those cases where
> > the loop update condition cannot be hypotheticalized).
>
>
>
> Is this even possible? This would require Perl to know which iteration is
> going to be the last one. In many cases there is no way to know this:
>
> repeat {
> $num = rand;
> print $num;
> NEXT {print ',';}
> LAST {print "\n";}
> } while $num < 0.9;
>
> If rand is a true random-number generator it would take a time machine to
> determine whether to call NEXT or LAST.
> (Sorry for the double post.)
Depends on when it fires I guess. Your example might be equivalent to
this perl5ish:
while (1) {
$num = rand;
print $num;
last if $num < 0.9;
print ","; # NEXT
}
print "\n"; # LAST
-Scott
--
Jonathan Scott Duff
[EMAIL PROTECTED]
