Online PHP editor | output for k91RV

<?php class FakePromise { public $value; public function __construct($value) { $this->value = $value; } public function getValue() { return $this->value; } } function coroutine() { $a = yield new FakePromise(1); $b = yield new FakePromise(2); return $a+$b; } function makeRunnable($fn) { return function(...$args) use ($fn) { $gen = call_user_func_array($fn, $args); while ($gen->valid()) { $current = $gen->current(); if ($gen === null) { $current = $gen->getReturn(); } if ($current instanceof FakePromise) { $gen->send($current->getvalue()); } else { $gen->send($current); // handle none Promises } } return $gen->getReturn(); }; } $fn = makeRunnable('coroutine'); echo call_user_func($fn);