> Summary: I think these should all simply break down into a single
> Boolification test of some sort, as occurs already with operator
> overload.
Counter-summary: Although the high and low precedence binary ops could be
rolled together, the current version of operator overloading
is inadequate. An overloaded conjunction or disjunction
is *not* an instance of boolification unless I *define*
it to be so.
> >LOGHIGHAND Called in && context
> >LOGHIGHOR Called in || context
> >LOGLOWAND Called in and context
> >LOGLOWOR Called in or context
> >LOGIFELSE Called in ?: context
>
> I don't see that those should be any different from one another.
> The essential feature in all of them is simply a Boolean test.
Not necessarily. What if I am setting up a class that represents expressions
and want to be able to say:
$x = ExprNode->new();
$y = ExprNode->new();
$z = ExprNode->new();
$exprtree = $x + $y < $z && $z > $x * $y;
I can currently overload + < > * to do this, but not &&. That's broken.
> if ($whatever) { A }
> else { B }
>
> Why should that any of those be different than
>
> $whatever ? A : B;
Because one is a control and one is an operator (i.e. yields a value).
What if I want that value to be another ExprTree?
> Please also consider this:
>
> % perl -MO=Deparse -e 'B() if A()'
> B if A ;
> -e syntax OK
>
> % perl -MO=Deparse -e 'A() && B()'
> B if A ;
> -e syntax OK
>
> The reverse if/unless tests are really just flow-control logicals
> written funny (or vice versa, if you prefer). Since "A && B" really
> becomes "B if A", you'll have to tackle that there, too. And even
> if it didn't, it would seem something to be addressed.
Agreed. This is an internal optimization that that would need to be addressed
if boolean connectives were made overloadable.
> And what about the negations? Will !A trigger something special?
Yes. NOT must be overloadable too.
BTW, this is not just theoretical yearnings. I have written three modules
in the past year that do not work as well as they could, simply because it
is not possible to overload && and ||.
Damian
