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Date: Wed, 16 Jul 2014 20:52:21 +0100
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To: Rowan Collins <rowan.collins@gmail.com>
Subject: Re: [PHP-DEV] [RFC] Scalar Type Hinting With Casts (re-opening)
From: ajf@ajf.me (Andrea Faulds)


On 16 Jul 2014, at 20:47, Rowan Collins <rowan.collins@gmail.com> wrote:

> I think this would be quite nice - keeps things relatively short =
without introducing so much punctuation that it starts looking like a =
Perl script ;)
>=20
> The only problem is that either you need a whole set of functions =
(safe_int($foo), safe_float($foo), etc) or you need some format for that =
second argument, which gets you into some odd meta-validation: if you =
take a string, or an integer (expected to be in the form of a constant =
like PHP_INT), then it would be possible to write safe_cast($foo, $bar), =
and now we need rules on validating $bar, and what happens if it's =
wrong.
>=20
> The magic form with a keyword like you've written avoids that, but it =
feels kind of weird - like when SQL date functions take things like =
"day" and "hour" as barewords rather than strings.

Perhaps this could work?

    if (safe_cast((int!)$foobar)) {
        $foobar =3D (int!)$foobar;
    } else {
        $foobar =3D 1;
    }

With safe_cast() being a pseudo-function =E0 la isset() et al.

I=92m not really sure adding a new set of safe casts is really such a =
good idea; we don=92t really need (int!) even, we could just have =
can_cast_int_strict (or something like that) given that (int) and (int!) =
do the same thing for the non-failure cases.

And perhaps it=92d be better just to leave this to scalar type hints, =
I=92m not sure I really want to add this stuff...
--
Andrea Faulds
http://ajf.me/