Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:81796
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain tutteli.ch designates 80.74.154.78 as permitted sender)
To: "'Dmitry Stogov'" <dmitry@zend.com>,
	"'Sebastian Bergmann'" <sebastian@php.net>
Cc: "'PHP Internals'" <internals@lists.php.net>
References: <CA+9eiLuueVvYgT-fhCvzBSxzoDioinpc5Eok5OQtGDBG1FZM=w@mail.gmail.com>	<CAGa2bXbQsh4qWizf+1k15+BvdNGqjD8OCPGx7S=WAhCPqimXuA@mail.gmail.com>	<CA+9eiLsnyoxPO7b3oQEN5RbqVE0K6o-01FQR7SYfZQD=QLka5Q@mail.gmail.com>	<00c101d04049$ca411ec0$5ec35c40$@tekwire.net>	<CA+9eiLtfpnBH4H_uyM5yZe8M2C_70XKgy3aJ7P6VwdOk0psnQQ@mail.gmail.com>	<54D1CA7C.8060204@php.net> <CA+9eiLupaFmejNfSKMyGTF=iOrMJfttpdwknpTGadwTgv4zb1w@mail.gmail.com>
In-Reply-To: <CA+9eiLupaFmejNfSKMyGTF=iOrMJfttpdwknpTGadwTgv4zb1w@mail.gmail.com>
Date: Wed, 4 Feb 2015 10:38:41 +0100
Message-ID: <003f01d0405e$5d1bf080$1753d180$@tutteli.ch>
MIME-Version: 1.0
Content-Type: text/plain;
	charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Thread-Index: AQI+MKsMv6zrm7KCv5jpZIs/BqhffwHJ9dvJAVdrBXgBsC3UswHm0N93AfLB7ygB8dXUSpuvcIJQ
Content-Language: de-ch
Subject: AW: [PHP-DEV] What do we need strict scalar type hints for?
From: php@tutteli.ch ("Robert Stoll")

> -----Urspr=C3=BCngliche Nachricht-----
> Von: Dmitry Stogov [mailto:dmitry@zend.com]
> Gesendet: Mittwoch, 4. Februar 2015 10:26
> An: Sebastian Bergmann
> Cc: PHP Internals
> Betreff: Re: [PHP-DEV] What do we need strict scalar type hints for?
>=20
> hi Sebastian,
>=20
> Do you like the proposal with declare() switch?
> Don't you afraid of sin(1) break? (it's just an example, telling how =
many things may be broken).
>=20
> Thanks. Dmitry.
>=20
> On Wed, Feb 4, 2015 at 10:30 AM, Sebastian Bergmann =
<sebastian@php.net>
> wrote:
>=20
> > Am 04.02.2015 um 08:25 schrieb Dmitry Stogov:
> > > The idea of that RFC was an ability to have zero-cost assert().
> >
> >  But an assert() is still in the body of a function or method and  =
not
> > part of its signature. That is what I want scalar type  declarations
> > for.
> >
> >
> > --
> > PHP Internals - PHP Runtime Development Mailing List To unsubscribe,
> > visit: http://www.php.net/unsub.php
> >
> >

Personally I am not in favour of the declare approach because the user =
will need to switch between strict context and non-strict context which =
will be quite challenging, anti-efficient (in terms of productivity) and =
most probably another source for bugs.
Yet, I have to defend Andrea's RFC here since the claims made that it =
will break all kind of existing code is just not true (or I got the RFC =
completely wrong).

sin(1) would only be broken if and only if the user has decided to use =
it in a strict mode. Consider the following:

User A writes the file index.php

<?php
$a =3D sin(1); //perfectly fine
include 'test_strict.php'
?>

and user B writes test_strict.php

<?php
declare(strict=3D1);
$b =3D sin(1); //will fail and that's ok [*] since the user decided to =
be in strict mode
?>

As far as I can tell user A which want to code in non-strict mode could =
do so also in the future - no error is reported, no problem at all. Only =
user B would get the error and only because he/she wanted to be informed =
when his/her code is not strict.

[*] we could actually distinguish between int literals/constants and int =
variables. The above case would be fine as well since 1 can be int or =
float (pretty much as Haskell is handling it)