Online PHP editor | output for RYBmm

<?php namespace fiberEnabled { /** @return iterable<int> */ function fibonacciSequence(): iterable { $a = 0; $b = 1; while (true) { yield $a; // Imagine if this had to yield a Promise: // All callers would also have to return a promise and know how to wait for it to resolve if (\Fiber::getCurrent()) { \Fiber::suspend(); } $c = $a; $a = $b; $b += $c; } } function fetch5th(): int { foreach (fibonacciSequence() as $key => $i) { if ($key === 19) { return $i; } } } function fetchFirstTen(): array { $result = []; foreach (fibonacciSequence() as $key => $i) { $result[] = $i; if ($key === 9) { return $result; } } } function file_get_contents(string $file): string { if (!\Fiber::getCurrent()) { return \file_get_contents($file); } $stream = fopen($file, 'r'); \stream_set_blocking($stream, false); \stream_set_read_buffer($stream, 0); $data = ''; while (!\feof($stream)) { \Fiber::suspend(); $partial = \stream_get_contents($stream, length: 4); // Simulate read latency var_dump($partial); $data .= $partial; } \fclose($stream); return $data; } // NOTE: A real fiber event loop would be able to pool these and 'await' them alternatingly. // If it was waiting for a network request they may return in a different order. // Fibers can repeatedly suspend and let other fibers continue while waiting for an external condition. function fiberAll(array $fibers): array { foreach ($fibers as $key => $fiber) { if (!$fiber->isStarted()) { $fiber->start(); } while ($fiber->isSuspended()) { echo 'Fiber suspended, resuming...', "\n"; $fiber->resume(); } } return $fibers; } } namespace { file_put_contents('/tmp/test123', 'Some test text data'); // Whether used directly, outside of an event loop... print_r(\fiberEnabled\fetch5th()); echo "\n"; print_r(\fiberEnabled\fetchFirstTen()); print_r(\fiberEnabled\file_get_contents('/tmp/test123')); echo "\n"; // Or used as part of an event loop... $fibers = \fiberEnabled\fiberAll([ 'fetch5th' => new Fiber(\fiberEnabled\fetch5th(...)), 'fetchFirstTen' => new Fiber(\fiberEnabled\fetchFirstTen(...)), 'fileContent' => new Fiber(fn () => \fiberEnabled\file_get_contents('/tmp/test123')), ]); print_r($fibers['fetch5th']->getReturn()); echo "\n"; print_r($fibers['fetchFirstTen']->getReturn()); print_r($fibers['fileContent']->getReturn()); echo "\n"; }