3

I have a method in my class that accepts an object by reference. It decorates that object to extend the functionality.

basically...

public function addObject( &$object ) {
    $object = $this->decorate( $object );
}

I'm trying to write a convenience method addObjects() but it's not changing $object

This does not work...

public function addObjects( array &$objects ) {
    foreach( $objects as $object ) {
        $this->addObject( $object );
    }
}

I've tried a bunch of other routes but none have worked. I'm sure there's a way to do this, but it's escaping me. Maybe i've been staring at my computer too long.

Here's is a live example

http://ideone.com/tfopZ

Update

It seems there's no way other than to pass references when creating the array of objects

$objects = array( &$object1, $object2 ); //object1 will be decorated, object2 will not
$thing->addObjects( $objects );
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2
  • 1
    What happens if you set $objects = NULL in the function, and then var_dump() after the function has returned? Commented Nov 17, 2010 at 3:29
  • I just edited my answer to include another solution. Less hacky but you need to reassign your variables. Commented Nov 17, 2010 at 19:39

2 Answers 2

Reset to default
4

EDIT: another solution I can think of is to reassign your local objects to the array elements, like this:

$dec->addObjects( $a);
$std = $a[0];
print_r( $std );

Now $std is a reference to the decorated object.

decorator Object
(
    [decoratee:protected] => stdClass Object
        (
        )

)

I don't have a practical solution yet, but I think I can explain the behavior.

This happens because object references are passed by value by default. So in your example, the array actually contains a new reference to the object:

$a = array( $std );

So you have two references to the object:

  1. One created as you initialize the object, and
  2. One owned by the array.

It explains why printing $std gives you the same object as if it hadn't been decorated, because you are looking at $std as it was created here, which isn't the same as the one contained in the array:

$std = new StdClass;

Your decorator and test objects are working with the same object in your array, which is why dumping $a from your calling code produces the decorated object.

Currently the only way I can think of to coax PHP into modifying your object, is to pass it by reference to your array, like this:

$a = array( &$std );

Of course, that'll probably be a rather hacky solution and may not suit your needs.

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1 Comment

This does work, so it is definitely the cause but you are right it's a bit hacky. I'm still searching for a better way. I've tried removing the array and adding unlimited objects using func_get_args() but no luck there either
1

I think the problem is foreach( $objects as $object ). This construction will make a copy of the array elements into $object. You need to do foreach( $objects as & $object ).

foreach in the PHP manual

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1 Comment

Okay, there's my PHP v4 fallback version: foreach( $objects as $i => $na ) { $object = & $objects[i];

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