[EMAIL PROTECTED] wrote:

Well, we see the same kind of thing with standard interval arithmetic:

   (-1, 1) * (-1, 1) = (-1, 1)
   (-1, 1) ** 2 = [0, 1)

The reason that junctions behave this way is because they don't
collapse.  You'll note the same semantics don't arise in
Quantum::Entanglement (when you set the "try to be true" option).

But you can force a collapse like this:

my $x = 4 < $j;
if $j < 2 { say "never executed" }



By which I mean:

   my $x = 4 < $j;
   if $x < 2 { say "never executed" }



Uh, I'm not sure this does what I think you wanted to say it does. ;) $x is a boolean, unless < returns a magical object... in which case, the magical part of $x ought to be a reference to the original $j, no?

I'm wonding if we should allow a method that returns a junction that is
allowed to collapse the original:

   if 4 < $j.collapse and $j.collapse < 2 {
       say "never executed";
   }

But that's probably not a good idea, just by looking at the
implementation complexity of Quantum::Entanglement. People will just
have to learn that junctions don't obey ordering laws.


Well, I suspect that junctions will have to be references and just collapse every time. Observe:

my $x = any(1, 2, 3, 4, 5);
print "SHOULD NOT RUN" if (is_prime($x) && is_even($x) && $x > 2);

This only works if $x collapses. Same for matching junctioned strings:

my $a = any (<a b c>);
print "Boo!" if $a ~ /a/ and $a ~ /b/ and $a ~ /c/;

(perhaps I meant to use ~~, I don't quite remember :) )

Either way, autocollapsing juntions is a Good Thing IMHO, and the only remaining confusion (to go back to my initial post) is that the only case that doesn't work is when you instance a junction twice as a pair of same literals:

print "SUCCESS, unfortunately" if (is_prime(any(1, 2, 3, 4, 5)) && is_even(any(1, 2, 3, 4, 5)) && any(1, 2, 3, 4, 5) > 2);

Hope I'm making sense. Been a hard day at work. ;)

   Miro



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