Question

The below is example2 from php.net’s splobjectstorage documentation.
The lines using $s[$o1] and $s[$o2] is syntax I’m not familiar with and haven’t seen yet for objects (still learning)

Is this a standard way of fetching properties from an object that would work with any class I’ve created?

Is this instead using a magic method or additional programmed functionality to create this syntax for just this class?

<?php
// As a map from objects to data
$s = new SplObjectStorage();

$o1 = new StdClass;
$o2 = new StdClass;
$o3 = new StdClass;

$s[$o1] = "data for object 1";
$s[$o2] = array(1,2,3);

if (isset($s[$o2])) {
var_dump($s[$o2]);
}
?>

http://php.net/manual/en/class.splobjectstorage.php

Answer 1

You can use the square bracket syntax for arrays and all classes that implement the ArrayAccess interface (which SplObjectStoragedoes).

Example:

class MyObjectStorage implements ArrayAccess {
    public function offsetExists($offset) {}

    public function offsetSet($offset, $value) {
        echo "Set $offset to $value.";
    }

    public function offsetGet($offset) {
        echo "Get $offset.";
    }

    public function offsetUnset($offset) {}
}

$list = new MyObjectStorage();
$list['foo'] = 'bar'; // prints "Set foo to bar.";

See http://php.net/ArrayAccess for more information.