Just a note about using overloaded properties in PHP 5.2.0, since GPC
are now objects (SuperGlobal)
In PHP 5.2.0 (fixed in 5.2.1), all overloaded properties (using magic
method __get()) are returned in "read-only" context. If you try to
write to an overloaded array, or directly loop with foreach, PHP 5.2.0
throws a fatal error. For example:
$my_obj // a stdObj with overloaded property "some_array" (which is an array)
// -- these work
$my_obj->some_array = array('foo'=>'bar'); // call __set() and sets the array
echo $my_obj->some_array['foo']; // calls __get(), returns the array
in read context, and echos the 'foo' element
// -- these do not work
$my_obj->some_array['far'] = 'boo'; // calls __get(), returns the
array in read context, and attempts to write to read-only. Causes
fatal error.
// solution
$a = $my_obj->some_array; //calls __get(), and assign to new var $a
$a['far'] = 'boo'; // sets the 'far' element in $a
$a = $my_obj->some_array = $a; // calls __set(), setting the some_array to $a
foreach( $my_obj->some_array as $foo) { // calls __get(), returns the
array in read mode, and attempts to loop.
// Causes
fatal error, because foreach requires var be passed by reference.
//solution
$a = $my_obj->some_array; //calls __get(), and assign to new var $a
foreach( $a as $foo) { // passes new var $a by reference
Now, there is one catch, and that is an ArrayObject/ArrayIterator
object. They return properties in read/write context. (This applies to
our new SuperGlobal objects)
$my_arrayObject // an ArrayObject with property "some_array" (which is an array)
$my_arrayObject['some_array']; // return the array $some_array in
read/write context
$my_arrayObject['some_array']['far'] = 'boo'; // this works as the
array is in read/write context
foreach($my_arrayObject['some_array'] as $foo) { // Causes fatal error
as foreach requires to be passed by reference
//solution
$a = $my_arrayObject['some_array']; // assigns to new var $a
foreach( $a as $foo) { // passes new var $a by reference
Just something to keep in mind when using our new SuperGlobal ($_POST,
$_GET, $_COOKIE) objects. Also, this only applies to PHP 5.2.0, which
is default in the latest stable Debian, etch, so we have to "support"
this bug.
NOTE: you can also overcome this by setting the __get to return by
reference (function & __get() {) if, and only if, your parent class
allows for it.
I hope I made sense through all that :)
--
Matt Read
http://mattread.com
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