NYCPHP Meetup

[Dan Cech]

Alexander wrote:
> Thank you for detailed explanation...basically I was trying to do the
> following:
> 
> Object of the base class($objBase) containing some data which I want to
> copy to object of the derived class($objA). So I was looking for different
> approches to this 'problem', and I was questioning myself if it is
> possible to do that with type-casting, which you said is not supported in
> PHP :) I guess it's good :)

In PHP4 you could use a variant of the factory pattern, something like:

class Base
{
   var $a;
}

class A
{
   var $a;
   var $b;

   function &frombase(&$base)
   {
     $a =& new A();
     $a->a =& $base->a;

     return $a;
   }
}

$obj =& new Base();

$obj = a::frombase($obj);

Note the use of the assign-by-reference operator, which should ensure 
that any internal and external references are kept intact (I think).

Dan