Naive PHP Router

router.php

<?php
    function createRoutes(){
        $routes = array();
        array_push($routes, ['hello'    => hello()]);
        array_push($routes, ['hello123' => hello123()]);
        return $routes;
    }

    function hello(){
        return 'Hello World !';
    }
    function hello123(){
        return 'I am not';
    }

    $start = array_column(createRoutes(), 'hello');
    print_r($start); # => Array
                     # (
                     #   [0] => Hello World !
                     # )
    
?>

The only advantage I know of this solution is much cleaner code, compared to many GETs.
With fewer functions the performance is not too much reduced.