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Date: Thu, 17 Apr 2008 15:10:44 -0300
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To: Stanislav Malyshev <stas@zend.com>
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Subject: Re: [PHP-DEV] [RFC] Strict type hints (parameter and return value)
From: jarismar_silva@adplabs.com.br (Jarismar Chaves da Silva)

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I like and will use it a lot... sometimes you simple cannot trust on php 
dynamic type convertion, please see the following example
<?php
function check_user($user_id) {
    if ($user_id == 0) {
       // root user
    } else if ($user_id > 0 && $user_id < 1000) {
       // special admin users
    } else {
       // standard users
    }
}
?>
Now if someone thinks $user_id is the user login name and call 
check_user('<login_name>');
'<login_name>' will be converted to 0 (zero) as per php automatic string 
to numeric convertion and this user will be handled as being the root 
user. In this case strict comparison "===" is not apropriate, and I'm 
forced to verify the parameter against is_numeric.
I much simpler approach would be...
<?php
function check_user(int $user_id) {...}

Also I think this is a basic prerequisite to allowing function overload 
on php OO side in the future ;)

Thanks,
Jaris.

Stanislav Malyshev wrote:
> Hi!
>
>> So:
>> function foo($var) { if(!is_int($var)) { throw new exception('not 
>> int'); }}
>
> What's the use of such code? If $var is '1' and not 1, what's the use 
> of throwing an exception and having to handle it later (basically by 
> failing the task, since you don't know how to do foo() now) - instead 
> of just doing with that 1 what was intended for? There's no any 
> difference between 1 and '1' that can be important to anybody. Only 
> difference is the way it is represented in underlying bits in zvals, 
> about which nobody should ever care. That's like making function that 
> would accept only arguments that has 3'rd bit of pointer set to 1 and 
> 5th bit set to 0, and reject all others. No sane application should 
> ever behave this way. Writing such function is just plain wrong, it 
> replaces the substance of programming with nitpicking over the details 
> that are not important. Whole phenomenon of dynamic languages has 
> grown on the principle of liberating people from caring for bits and 
> concentrate on substance, and now you try to drag the bits back in.
>
>> which is called like this in both cases, maybe with a try catch etc etc:
>> foo((int) $baz['bar']);
>
> So every time you call foo you need try/catch? And that's supposed to 
> be _good_?

-- 

*Jarismar Chaves da Silva, M.Sc.*


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