Michele Dondi writes:
> On Tue, 29 Jun 2004, Rafael Garcia-Suarez wrote:
>
>
> > Difficulties: define "history" of a function w.r.t. threads; closures;
> > and system side-effects (writing to files, locking them etc.)
>
>
> On Tue, 29 Jun 2004, Mark A. Biggar wrote:
>
> > Besides we already have MTOWTDI with local() and hypotheticals.
>
> (i) I think it's temp() in Perl6, (ii) I don't know what hypotheticals
> are.
Hypotheticals are those C<let> things from Apocalypse 5. They are best
illustrated by example:
my $x = 5;
try {
let $x = 10;
die; # unsuccessful exit from block
}
# $x is 5 again
try {
let $x = 10;
} # successful exit from block
# $x is now 10
They're a way of making a hypothesis, and then if that hypothesis leads
to failure, "undoing" the hypothesis since it was false. It's really
neat stuff.
See Whatif.pm for a Truly Evil Perl 5 implementation of this kind of
thing. Don't look at the source: you might vomit.
Luke
> Anyway, guys, I'll take your word for it...
>
>
> Michele
> --
> You know, you would learn a lot more mathematics from a mathematics
> book than from a Mathematica book.
> - Dave Rusin in sci.math, "Re: A Klein Bottle has no inside or outside."
