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Subject: Re: [PHP-DEV] Re: Internal casting of objects as array keys
From: aidan@php.net ("Aidan Lister")

Andi, any interest in this?

"Aidan Lister" <aidan@php.net> wrote in message
news:20040525143059.95129.qmail@pb1.pair.com...
> Hi Andi,
>
> Okay, it's not as simple as I thought it was - and you're correct, the
> behaviour has not changed for php4/5.
>
> Objects in both PHP4 and PHP5 will throw an error if you use the method
> $blah[$someobject] = 'val'; (first method)
> Warning:  Illegal offset type
>
> However, both do not throw an error if you use $blah = array($someobject
=>
> 'val'); (second method)
>
> When we compare this behaviour with resources, it gets interesting. A
> resource is casted to an interger when used as an array key for the first
> method, but not the second.
>
> This raises a number of questions:
> 1) Should the behaviour of method 1, and method 2 be the same.
> 2) Should the behaviour of objects be the same as resources (in the
context
> of casting for use as an array key)
>
> Below is a sample script which shows the differences
>
> --------------------
> <pre>
> <?php
> // Create a sample object
> class id_obj { var $_id; function id_obj($id) { $this->_id = $id; } }
> // Create two new objects
> $id1 = new id_obj(1);
> $id2 = new id_obj(2);
> // Add them to an array with two different methods
> $array = array(); $array[$id1] = 'sdf';
> $array2 = array ($id1 => 'id1', $id2 => 'id2');
> echo "objects: first method:\n";
> var_dump($array);
> echo "objects: second method:\n";
> var_dump($array2);
>
> // Create two resources
> $fp1 = fsockopen("www.example.com", 80, $errno, $errstr, 30);
> $fp2 = fsockopen("www.example.com", 80, $errno, $errstr, 30);
> // Add them to an array with two different methods
> $resarray = array(); $resarray[$fp1] = 'fp1';
> $resarray2 = array($fp1 => 'fp1', $fp2 => 'fp2');
> // Show the result
> echo "resources: first method:\n";
> var_dump($resarray);
> echo "resources: second method:\n";
> var_dump($resarray2);
> ?>
> </pre>
> --------------------
>
> The output:
>
> -----------
> Warning:  Illegal offset type on line 9
> objects: first method:
> array(0) {
> }
> objects: second method:
> array(0) {
> }
> resources: first method:
> array(1) {
>   [2]=>
>   string(3) "fp1"
> }
> resources: second method:
> array(0) {
> }
> --------------
>
> Thanks.
>
>
>
> "Andi Gutmans" <andi@zend.com> wrote in message
> news:5.1.0.14.2.20040525161238.061c8f78@127.0.0.1...
> > This code doesn't seem to have changed. Can you send me a 3-4 liner
which
> > errors out in PHP 4 and not in PHP 4?
> >
> > Thanks,
> >
> > Andi
> >
> > At 11:03 PM 5/25/2004 +1000, Aidan Lister wrote:
> > >I'm going to go ahead and post this as a bug, unless there is a reason
> noone
> > >replied...
> > >
> > >"Aidan Lister" <aidan@php.net> wrote in message
> > >news:20040522064028.3397.qmail@pb1.pair.com...
> > > > Hello devs,
> > > >
> > > > I'd like to discuss the use of objects as array keys.
> > > >
> > > > <?php
> > > > class idobject {
> > > >     private $_id;
> > > >     function __construct ($id) { $this->_id = $id; }
> > > >     function __tostring () {  return (int)$this->_id; }
> > > > }
> > > >
> > > > $blah1 = new idobject(1);
> > > > $blah2 = new idobject(2);
> > > > $blah3 = new idobject(3);
> > > > $blah4 = new idobject(4);
> > > >
> > > > $array = array (
> > > >  $blah1 => 'blah1',
> > > >  $blah2 => 'blah2',
> > > >  $blah3 => 'blah3',
> > > >  $blah4 => 'blah4',
> > > >  );
> > > >
> > > > echo "<pre>";
> > > > var_dump($array);
> > > > echo "</pre>";
> > > > ?>
> > > >
> > > > In PHP4 this results in an error,
> > > > In PHP5 there is no error, the array is simply empty.
> > > >
> > > > An array key can only be a string/int, thus, when someone attempts
to
> use
> > >an
> > > > array as a key would it not make sense to cast the object?
> > > >
> > > > This behaviour would then be consistant with resources.
> > > >
> > > > Regards,
> > > > Aidan
> > >
> > >--
> > >PHP Internals - PHP Runtime Development Mailing List
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