Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:105363
MIME-Version: 1.0
References: <CAG9XoMS3xwNEsSvFaad5ExK4o9dhrKG9yaP2enp+yRQDmpr4Ow@mail.gmail.com>
 <CA+kxMuS7DV-iPyEBcaC0-d3W5LmsaawjF=U+ySND59L+dZ9F7Q@mail.gmail.com>
 <HscPQyDDQ0TcOQk9Ljmp2Ebf7fmL1DJnxYxmryg7A2XeKLUh--8H6YQNNJ_U418pVdNCW_6QZuJ55FBtMlPtLpY8_uNfNXd7NZrydANpHKc=@protonmail.com>
 <9fee0f79-a77d-c0f1-ec24-efa4dd587f91@hristov.com> <CAG9XoMTQf4oiGY8Hchk0iWQfNTsaGk7EcmHNa=_XTcSNDztNPQ@mail.gmail.com>
 <71E9312E-C4A6-44EB-AB1C-D8E063EB946A@koalephant.com> <CAG9XoMRVtA7deyDF-35+qus-utQjzHpxCO-3nwBjrHwyUubOCw@mail.gmail.com>
 <91A050D6-0755-4CE4-BE1C-01BDCC618EA1@koalephant.com>
In-Reply-To: <91A050D6-0755-4CE4-BE1C-01BDCC618EA1@koalephant.com>
Date: Tue, 23 Apr 2019 16:54:09 +0200
Message-ID: <CAG9XoMROicL5U6HVrB6RuD3t+Uz-X1W+1v5OCUDFRZYdSR3QEw@mail.gmail.com>
To: Stephen Reay <php-lists@koalephant.com>
Cc: PHP Internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary="000000000000983c1d058733c2d5"
Subject: Re: [PHP-DEV] Object Type Casting Reloaded
From: benjamin.morel@gmail.com (Benjamin Morel)

--000000000000983c1d058733c2d5
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

@Stephen Reay <php-lists@koalephant.com>

> In languages without type hinting (e.g. JavaScript) - the =E2=80=9Cboiler=
 plate=E2=80=9D
you=E2=80=99re trying to remove is also common, e.g. using `typeof` in Java=
Script.

It's also very common to *not* check types in JavaScript... I assume the
absence of type hints is partly responsible for this, and a reason why
quite a lot of JS developers turn to typed preprocessors, such as
TypeScript.

> Assigning a variable to itself, because you want to check its type is the
weirdest concept I=E2=80=99ve heard in a long time.

I assume you're speaking of the foreach() example; sure, used this way, it
looks like a self-assignment, but in most cases it's not, it's an inline,
checked type-hint:

    // (assuming the 'as' syntax, now that the cast syntax has been buried)
    $foo =3D $entityManager->find(User::class, 123) as User;

You're effectively adding, **inline and with just a few chars**, an
additional type-hint and runtime check to the value. I wouldn't call this a
no-op.

> You want to add more capability to enforce type checking - I get that,
and I share that goal. But when we already have pretty common, intuitive
syntax to do so in one situation, I don=E2=80=99t see why you wouldn=E2=80=
=99t adopt the
same syntax elsewhere.

While I don't agree with you on many points, I appreciate that we share the
same goal somehow, and hope that we can find common grounds. I would
personally not be against variables typed on declaration, but even though
this probably does not make sense, I'm somehow more comfortable with:

    function test(string $name) {
        $name =3D 123;
    }

than:

    string $name =3D 'Ben';
    $name =3D 123;

I guess that I could be more comfortable with this approach if we had a
switch, such as `declare(locked_types=3D1)`, that would enforce the type of
the variable throughout its lifetime. This may come at a huge runtime cost,
though.

- Ben

--000000000000983c1d058733c2d5--