超越PHP - Exceed PHP: Overloading

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Overloading
01-Sep-2004 02:39
For those using isset():

Currently (php5.0.1) isset will not check
the __get method to see if you can retrieve a value from that function.  So
if you want to check if an overloaded value is set you'd need to use
something like the __isset method below:

<?php

class
foo
{
    public $aryvars = array();

    function
__construct() {}

    function __get($key)
    {
        return
array_key_exists($key, $this->aryvars) ? 
              
$this->aryvars[$key] : null;
    }
    
    function
__isset($key) {
        if (!$isset = isset($this->$key)) {
      
     $isset = array_key_exists($key, $this->aryvars);
        }
  
     return $isset;
    }
    
    function __set($key,
$value)
    {
        $this->aryvars[$key] = $value;
   
}
}

echo '<pre>';
$foo = new foo();
$foo->a =
'test';
echo '$foo->a == ' . $foo->a . "\n";
echo
'isset($foo->a) == ' . (int) isset($foo->a) . "\n";
echo
'isset($foo->aryvars[\'a\']) == ' . isset($foo->aryvars['a']) .
"\n";
echo '$foo->__isset(\'a\') == ' .
$foo->__isset('a') . "\n";
var_dump($foo);

?>
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