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Date: Wed, 11 Aug 2004 23:37:30 -0400
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To: Dan Ostrowski <dan@ostrowski.cc>
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Subject: Re: [PHP-DEV] is_a() vs. instanceof
From: sean@caedmon.net (Sean Coates)

Dan Ostrowski wrote:
> On Tuesday 10 August 2004 7:36 pm, Hans Lellelid wrote:
>>    The class must be loaded in order to perform an instanceof check!
*snip*
> Am I misunderstanding you?
> 

consider the following:

<?php

class Foo {}

$foo = unserialize('O:3:"Foo":0:{}');

echo '$foo is_a Foo? '. (is_a($foo, 'Foo') ? 'yes' : 'no') ."\n";
echo '$foo instanceof Foo? '. ($foo instanceof Foo ? 'yes' : 'no') ."\n";

?>
outputs:
$foo is_a Foo? yes
$foo instanceof Foo? yes

and
<?php

//class Foo {}

$foo = unserialize('O:3:"Foo":0:{}');

echo '$foo is_a Foo? '. (is_a($foo, 'Foo') ? 'yes' : 'no') ."\n";
echo '$foo instanceof Foo? '. ($foo instanceof Foo ? 'yes' : 'no') ."\n";

?>
outputs:
$foo is_a Foo? no

Fatal error: Class 'Foo' not found in 
/home/sean/phpdoc/scripts/tmp/is_a.php on line 8

---

I realize that is_a is deprecated, but it's more convenient in this 
situation.

S