$attributes * @return Closure(XMLWriter): Generator */ function namespaced_attributes(string $namespace, array $attributes): Closure { return /** * @return Generator */ static function (XMLWriter $writer) use ($namespace, $attributes): Generator { foreach ($attributes as $key => $value) { $parts = explode(':', $key, 2); $name = array_pop($parts); $prefix = $parts ? $parts[0] : null; yield from namespaced_attribute($namespace, $prefix, $name, $value)($writer); } }; }