Online PHP editor | refs for msg5M

<?php class x { const LABELS = [ 'a' => 'Hello', 'b' => 'World' ]; const UNKNOWN_LABEL = 'unknown'; public static function test($module) { return self::LABELS[$module] ?? self::UNKNOWN_LABEL; } } $a = []; $a[] = x::test('a'); $a[] = x::test('b'); $a[] = x::test('c'); $a[] = x::test(null); var_dump($a);