Ugly Antipattern

antipattern.php

<?php
function globalvar($name, $action = 'get', $value = null) 
{
    static $cache = [];
    switch ($action) {
        case 'get':
            if (isset($cache[$name])) {
                return $cache[$name];
            }
            return null;
        case 'set':
            $cache[$name] = $value;
            return true;
    }
}