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Date: Wed, 10 Aug 2005 18:30:29 +0300
To: Derick Rethans <derick@php.net>
Cc: PHP Developers Mailing List <internals@lists.php.net>
In-Reply-To: <Pine.LNX.4.62.0508081150140.2940@localhost>
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Subject: Re: [PHP-DEV] type hinting throwing a fatal error
From: zeev@zend.com (Zeev Suraski)
References: <Pine.LNX.4.62.0508081150140.2940@localhost>

I don't think that's a good idea, regardless of implementation issues.

Calling to a function with the wrong arguments is something that should be 
dealt with when developing the application, not at runtime.  I think that 
throwing exceptions in all sorts of places encourages people to write 
'exception-oriented' apps, which is very messy.  Type hinting is also not 
exactly an OO thing, it's an object thing, and there's a difference.  PHP 
is filling up with a lot of builtin classes, as well as infrastructure 
classes, that actually simplify the lives of users, without them having to 
have a clue about object orientation.  Some examples that come to mind are 
SimpleXML, the SOAP classes and PDO.  On a long enough timescale - 
everybody using PHP will be using objects, and many (if not most) of them 
will be using them in procedural apps.  I see a big negative point in 
forcibly introducing these people to the concept of exceptions.

I believe we mentioned once the possibility of adding another error level, 
which is fatal - but still catchable by set_error_handler().  That is a 
good idea (which we should be doing either way).

Zeev

At 12:50 08/08/2005, Derick Rethans wrote:
>Hei,
>
>currently if you pass a wrong object's type to a typehinted parameter:
>
>         derick@kossu:~$ cat /tmp/foo.php
>         <?php
>         class foo {
>                 function bar(foo $a)
>                 {
>                 }
>         }
>
>         $a = new foo;
>         $a->bar(new stdClass);
>         ?>
>         derick@kossu:~$ php /tmp/foo.php
>
>         Fatal error: Argument 1 must be an instance of foo in 
> /tmp/foo.php on
>         line 3
>
>As type hinting is a new OO thing, it might perhaps make some sense to
>make this an exception instead - as this error might also happen for
>dynamic things by people who use the classes you designed. In that case
>having this fatal error to stop the whole application can be annoying.
>Opinions?
>
>Derick
>
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