Generators and Promises in PHP

gistfile1.php

<?php

// synchronous code
// fetch operations are blocking

$profile = fetchProfile('@kaja47');

$ids = [];
$cursor = '-1';
do {
  $fs = fetchFollowers($profile->id, $cursor);
  $ids = array_merge($ids, $fs->ids);
  $cursor = $fs->next_cursor_str;
} while ($cursor != "0")

return [$profile, $ids];



// asynchronous code
// fetch operations and flow function return promise
// flow is implemented here: https://github.com/kaja47/flow/blob/master/flow.php

flow(function() {
  $profile = (yield fetchProfile('@kaja47'));

  $ids = [];
  $cursor = '-1';
  do {
    $fs = (yield fetchFollowers($profile->id, $cursor));
    $ids = array_merge($ids, $fs->ids);
    $cursor = $fs->next_cursor_str;
  } while ($cursor != "0")

  yield [$profile, $ids];
});