Online PHP editor | refs for tTusL

<?php // thanks to metaultralurker on reddit for inspiration function call(callable $fn) { return $fn(); } function map(callable $fn, \Traversable $data) { return call(function () use ($fn, $data) { foreach ($data as $v) { yield $fn($v); } }); } function filter(callable $fn, \Traversable $data) { return call(function () use ($fn, $data) { foreach ($data as $v) { if ($fn($v)) { yield $v; } } }); } $isNotZ = function ($x) { return $x !== 'Z'; }; $data = filter($isNotZ, map('strtoupper', call(function () { foreach (range('a', 'z') as $char) { yield $char; } }))); /* var_dump($data->current()); $data->next(); var_dump($data->current()); $data->next(); */ var_dump(iterator_to_array($data));