Gerard

<?php
/*
 *  This file will demonstrate call by reference (rather than call by value - this would create a copy/clone, rather than a reference).
 *   - Gerjo Meier
 */

 // Create an object from a class (instance)
$myChild  = new MyChild();

// Notice how we pass $myChild as an argument(, MyParrent will store a "reference" to $myChild).
$myParent = new MyParent($myChild);

// This should echo the value $someString (which has been given some value via the constructor) of MyChild):
echo $myChild->getSomeString();
echo $myParent->example();

// Update $someString: (mind you we do this via $myChild, and not $myParent!)
$myChild->setSomeString("- I am quite alright!");

// Both statements should echo the same string $someValue, eventho we only updated $myChild.
echo $myChild->getSomeString();
echo $myParent->example(); // Will echo the same value as it contains a reference to $myChild.



class MyParent {
    private $child;

    public function __construct ($child) {
        // Stores the reference to a "child" object for later use.
        $this->child = $child;
    }

    // Will output the $someString value of the $child class.
    public function example() {
        return $this->child->getSomeString();
    }
}

class MyChild {
    private $someString;

    public function __construct () {
        // Assign some default value for this example:
        $this->someString = "How are you doing mate? ";
    }

    // Getter for $someString
    public function getSomeString() {
        return $this->someString . " [via class: "  . __CLASS__ . "] <br /> ";
    }

    // Setter for $someString
    public function setSomeString($someString) {
        $this->someString = $someString;
    }
}

?>