comand_dispatcher.php

<?php

class A
{
}
class B
{
}
class C
{
}
$map = [
    A::class => function(A $a) {
        echo "A".PHP_EOL;
    },
    B::class => function(B $b) {
        echo 'B'.PHP_EOL;
    }
];

$bus = function (array $map): callable
{
    return function (object $cmd) use ($map): void
    {
        $name = get_class($cmd);
        if (!isset($map[$name])) {
            throw new Exception(sprintf('Command "%s" unknown', $name));
        }
        $map[$name]($cmd);
    };
};


$dispatch = $bus($map);
$dispatch(new A);
$dispatch(new B);
$dispatch(new C);