But, for the programmer, property which was set whith __set() and __get() ARE REAL, and must be use as real property.
Conclusion : if php provide __set() and __get() to simulate object property, all function in the language must interact with them as usual, even if property are not real.
So, an isset() call on a property wich was created witch __set() MUST return TRUE, and not FALSE.
And __set and __get functions are very interesting. Imagine a session object, for example :
class session
{
private $id = '';
private $data = array();...
function __get($dataName)
{
if (isset($this->data[$dataName]) == true)
return null;
else
return $this->data[$dataName];
} function __set($dataName, $dataValue)
{
$this->data[$dataName] = $dataValue;
}
}and you can do something like that :
$session = new session();
if (isset($session->idUser) == true) $idUser = $session->idUser; else #http location on a login page
And in login page :
$session = new session(); $session->idUser = 'aUser';
But in this case, isset() MUST RETURN A GOOD RESULT, true
Fred.
Daniel Schierbeck wrote:
> Catalin Trifu wrote:
>
>> Actually i think no property is created; not in the sense of
>> real object property.
>> The only "real" property of the object is $elem.
>> The $o->a, and $o->b are, IMHO, not object properties;
>> It is true that one can access $o->a and $o->b, but what is actually
>> returned is a member of the array $elem, and only because of the
>> implementation of the magic functions __set and __get.
>> isset() does test for an "actual" variable beeing set, which is
>> definetely
>> not the case.
>> I agree however that this is confusing. I am definetely puzzled by
>> the
>> usefullness of these methods since i consider this to be a real error
>> trap;
>> it would be so easy to fill up an object with values without knowing
>> what they are and what they are supposed to do and when developing some
>> kinda library, things can get really messy.
>> On my part I would stick with the usual declaration of properties
>> and not
>> use __set() and __get().
>> I think it's much cleaner to say:
>> class OO {
>> /** this is variable a and means ... */
>> public $a;
>> /** this is variable a and means ... */
>> public $b;
>> }
>>
>> cheers,
>> Catalin
>>
>>
>> ""Frédéric hardy"" <[EMAIL PROTECTED]> wrote in message
>> news:[EMAIL PROTECTED]
>>
>>> Yes.... but not :-).
>>>
>>> With you use these magic functions, when you write $o->a = 'foo', you
>>> create a property in the object. Not ? Even if it is stored in an
>>> array member, __set() create a property and __get() retrieve its value.
>>>
>>> Doc says :
>>>
>>>
>>>> The $name parameter used is the name of the variable that should
>>>> be set or retrieved.
>>>> The __set() method's $value parameter specifies the value that
>>>> the object should set set the $name.
>>>
>>>
>>> Conclusion :
>>>
>>> class OO
>>> {
>>> private $elem = array();
>>> public function __get ($prop)
>>> {
>>> if (isset($this->elem[$prop])) {
>>> return $this->elem[$prop];
>>> }
>>> else
>>> {
>>> return NULL;
>>> }
>>>
>>> public function __set ($prop, $val)
>>> {
>>> $this->elem[$prop] = $val;
>>> }
>>> }
>>>
>>> $o = new OO();
>>> echo isset($o->a) ? "yes\n" : "no\n"; # Must return false and return
>>> false effectively, cool
>>> $o->a = 'foo';
>>> echo isset($o->a) ? "yes\n" : "no\n"; # Must return false and return
>>> false effectively, NOT COOL
>>>
>>> Fred.
>>>
>>>
>>> Catalin Trifu wrote:
>>>
>>>
>>>> Hi,
>>>>
>>>> Is this really a bug. I think not.
>>>> There is no variable $o->a or $a->b in the class OO
>>>> there is only the variable $elem and $a and $b is a member
>>>> of that array
>>>> So ...
>>>> The fact that PHP5 provides __set and __get magic
>>>> functions does not mean that the actual variables exist with
>>>> that particular name in the class ?
>>>> Perhaps it would be nice to have a __isset magic function ?
>>>>
>>>> Cheers
>>>> Catalin
>>>>
>>>>
>>>>
>>>>
>>>>> <?php
>>>>>
>>>>> class OO
>>>>> {
>>>>> private $elem = array("a" => 1);
>>>>>
>>>>> public function __get ($prop)
>>>>> {
>>>>> if (isset($this->elem[$prop])) {
>>>>> return $this->elem[$prop];
>>>>> } else {
>>>>> return NULL;
>>>>> }
>>>>> }
>>>>>
>>>>> public function __set ($prop, $val)
>>>>> {
>>>>> $this->elem[$prop] = $val;
>>>>> }
>>>>> }
>>>>>
>>>>> $o = new OO();
>>>>>
>>>>> echo isset($o->a) ? "yes\n" : "no\n";
>>>>> echo isset($o->b) ? "yes\n" : "no\n";
>>>>>
>>>>> echo is_null($o->a) ? "yes\n" : "no\n";
>>>>> echo is_null($o->b) ? "yes\n" : "no\n";
>>>>>
>>>>> ?>
>>>>>
>>>>> I expected something like this:
>>>>>
>>>>> yes
>>>>> no
>>>>> no
>>>>> yes
>>>>>
>>>>> But got this:
>>>>>
>>>>> no
>>>>> no
>>>>> no
>>>>> yes
>>>>>
>>>>> It looks like isset() can't handle object properties correctly.
>>>>> I'll post the bug on php.net.
>>>>>
>>>>> --
>>>>> Daniel Schierbeck
>>>>
>>>>
>>>>
>>> --
>>> ===================================================================
>>> Frederic HARDY Email: [EMAIL PROTECTED]
>>> HEXANET SARL URL: http://www.hexanet.fr/
>>> ZAC Les Charmilles Tel: +33 (0)3 26 79 30 05
>>> 3, allée Thierry Sabine Direct: +33 (0)3 26 61 77 84
>>> BP 202 - 51686 REIMS CEDEX 2 FRANCE
>>> ===================================================================
>
>
> I personally find the __get() and __set() methods very usefull,
> especially when constructing object hierarchies. But, as Frédéric said,
> they're not sufficient. Either make isset() work with the __get() method
> or add a __isset() magic method.
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