PHP 5 supports the overloading of the __get() __set() methods, which are responsible for being called when a particular class variable is requested but doesn't explicitally exist.

<?php
    class anotherfoo {

        private $testvar = array ('test'=> 10);

        function __get($varname) {

            return $this->testvar[$name];

        }

        function __set($varname, $value) {

            $this->testvar[$name] = $value;
        }

    }

    $varinst = new anotherfoo();
    $varinst->test++;
    echo "The value of 'test' is {$varinst->test}";
?>