Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:67900
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: pass (pb1.pair.com: domain gmail.com designates 209.85.214.182 as permitted sender)
MIME-Version: 1.0
Sender: patrick.allaert@gmail.com
In-Reply-To: <1372258135.2410.22.camel@guybrush>
References: <CAA9esyS0YL=biVS37ix-yBea7RmZXPnhVk_xKjfz6x+gfN5LNw@mail.gmail.com>
	<CAL+t6cF9JTr9e=A15LvhfgN0DaV8_k4SuEDxQ408fNAAx=8Z_A@mail.gmail.com>
	<CAOX1NOfBPTggj6-WA=ArXjw1UvhUbVC=+FjCYvk6Bgp856biFg@mail.gmail.com>
	<CACwt+Je1vS7MkqShM8+FaDJmAoyaTDCWtTSOuOwG4iWUnyvKHA@mail.gmail.com>
	<CAMUwpuRC8WfrR26W+1hVgXDMt28OQXek68w=9YEGs2ueEiOewg@mail.gmail.com>
	<CACwt+JfoZPuTYk0S3stoDdAftcRB1hAspXNQU4EBkVaX2uiStw@mail.gmail.com>
	<CAH-PCH4BMFrjmNXDJXJ96QT9deWTi7P8P8OR-ZGcr6j=VQ5sig@mail.gmail.com>
	<1372258135.2410.22.camel@guybrush>
Date: Wed, 26 Jun 2013 18:33:38 +0200
Message-ID: <CACwt+Je+jXfb_7VC8yNuAbm=aZGFsC4MUFwMHdoNm_kfd6Rf+w@mail.gmail.com>
To: =?UTF-8?Q?Johannes_Schl=C3=BCter?= <johannes@schlueters.de>
Cc: Ferenc Kovacs <tyra3l@gmail.com>, Julien Pauli <jpauli@php.net>, Maxwell <Max@maxvandervelde.com>, 
	Sherif Ramadan <theanomaly.is@gmail.com>, Florin Patan <florinpatan@gmail.com>, 
	"internals@lists.php.net" <internals@lists.php.net>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Subject: Re: [PHP-DEV] Request for comments - new PHP feature: return typing
From: patrickallaert@php.net (Patrick ALLAERT)

Johannes,

2013/6/26 Johannes Schl=C3=BCter <johannes@schlueters.de>:
> So a function author doesn't trust himself and therefore we change the
> language syntax?

In the following example:

class Foo {
    public function bar($input) {
        $return =3D Baz::foo($input);
        if (!$return instanceof ReturnType)
            trigger_error("Cannot divide by zero", E_USER_ERROR); //
or throwing some RuntimeException

        return $return;
    }
}

Baz class can be from a 3rd party software and I may want to enforce
the fact that my Foo::bar() method returns an instance of ReturnType
or throw an exception or trigger an error.
This is moez easily written with this proposition:

class Foo {
    public function <ReturnType> bar($input) {
        return Baz::foo($input);
    }
}

With the same reasoning you had, you would avoid using parameter type
hinting and interfaces for your own project if there's no other people
using it.