Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:31006
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Message-ID: <74.B1.05050.EADEC964@pb1.pair.com>
To: internals@lists.php.net
Date: Tue, 17 Jul 2007 10:26:18 -0600
User-Agent: Thunderbird 2.0.0.4 (Windows/20070604)
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Subject: Type-hinted return values in PHP5?
From: david.nqd@gmail.com (David Duong)

Hello everyone,

I'm emailing to this list to suggest that "support for type-hinted 
return values"[1] be in added in PHP 5.y.x instead of PHP 6. 
Conceptually, this is the second half of "type-hints" already introduced 
in PHP 5.

This is why: When a programmer is designing an interface (the language 
construct), only what is accepted by the interface can be defined. 
Calling code is left with no idea of what the return type is going to be.

Even with great documentation, when designing an interface, it would be 
great to be able to take the responsibility of type checking return 
values from calling code onto the interface. To design a full interface, 
the interface designer should be able to say that a caller can call 
method X with input types Y and Z, then expect an object that implements 
interface Z to be returned. The caller should not have the 
responsibility of handling any other return types.

I'm looking forward to many of the upcoming features of PHP6, but PHP 6 
is far from being stable (?). This is a change will break any existing 
code and is not a big extension on how PHP, a weakly typed language (not 
necessarily a bad thing), handles types.

[1] http://oss.backendmedia.com/PhP60

ps - please let me know if posts like these should be posted elsewhere

Thanks,

David N. Q. Duong