PHP classes

[theS70RM]

Hi,

If I have a class that defines another class, how do i access the sub one from the main code.

So I have something like:
<?

class A{
   function A($foo){
       $this->p = new B($foo);  

   }

}

class B{
    function Z($myvar){
      $this->ID= $myvar;
        
   }

}

?>

But how would the main code go to access the ID property of B when an A has been defined... i.e. not like this:

$newvar = new A(666);
echo "B=".$newvar->p->ID;

how should it look?

thanks

Andy

[pbmods]

Heya, Andy.

The code you provided should work, since undeclared class members are assumed to be public in PHP.

A slightly more sane-looking approach might look something like this:

[CODE=PHP]
class A
{
public $child;

public function __construct( $subVal )
{
$this->child = new B($subVal);
}
}

class B
{
public $id;

public function __construct( $id )
{
$this->id = $id;
}
}

$newVar = new A(666);
echo "B = {$newVar->child->id}";
[/CODE]

Alternatively, you might want A to be a wrapper for B. In this case, you might consider using magic methods to make the child class accessible:

[CODE=PHP]
class A
{
protected $child;

public function __construct( $subVal )
{
$this->child = new B($subVal);
}

public function __get( $var )
{
if( isset($this->child->$var) )
{
return $this->child->$var;
}
else
{
return null;
}
}
}

class B
{
public $id;

public function __construct( $id )
{
$this->id = $id;
}
}

$newVar = new A(666);
echo "B = {$newVar->id}";
[/CODE]

In the second example, PHP will look for A::$id, which doesn't exist, so it will instead call A::__get('id'), which will check to see if B::$id has been set.

[theS70RM]

Thanks, that helps alot. I'll have a look at applying this to my code.

[theS70RM]

a couple of questions..

class A
{
  public $id;

  public function __construct( $id )
  {
    $this->id = $id;
  }
}

how come function __construct(){} doesnt work for me,

how come I cant declare public functions or variables?

Cheers

[pbmods]

You are probably running PHP 4, which does not support these features.

Check out this document to see what features are available.

[theS70RM]

oh ok,

Yea i am using php4 and cant upgrade at the mo.

cheers

Andy