Joe Gottman writes:
> 2) Do all of the xor variants have the property that chained calls
> return true if exactly one input parameter is true?
I would imagine not. C<xor> is spelled out, and by definition XOR
returns parity. On the other hand, the junctive ^ (one()) is exactly
one.
>
> 3) Is there an ASCII digraph for the | operator?
No. Just use C<zip>.
> 4) Do "==" and "!=" participate in chained comparisons, so that $a ==
> $b == $c evaluates to true if and only if all three are equal?
Yes. But not really. It evaluates true if $a == $b and $b == $c (while
only evaluating $b once). This may not be the same as all three being
equal if $a, $b, and $c are objects whose equality isn't transitive.
> Is $x > $y < $z a legal chaining? Or $x < $y lt $z?
Sure. It (rather confusingly) asks whether $y is less than both $x and
$z. The latter is too, and it's equivalent to:
$x < +$y and ~$y lt $z
> 5) Would it be possible for me to create a user-defined operator that
> does chaining?
Yes. You just have to be clever about your return values. A comparison
operator could return its right argument C<but true> or C<but false>.
To get them to short circuit is exactly the same problem as getting
other user-defined operators to short circuit, something that's been
adressed but I don't remember the answer to.
Luke
