function is_sorted_by()

in src/c/order.php [80:103]

• 21 lines of code
• 5 McCabe index (conditional complexity)

function is_sorted_by<Tv, Ts>(
  Traversable<Tv> $traversable,
  (function(Tv)[_]: Ts) $scalar_func,
  ?(function(Ts, Ts)[_]: num) $comparator = null,
)[ctx $scalar_func, ctx $comparator]: bool {
  $vec = Vec\cast_clear_legacy_array_mark($traversable);
  if (is_empty($vec)) {
    return true;
  }

  $comparator ??= (Ts $a, Ts $b) ==>
    /*HH_FIXME[4240] Comparison may not be useful on Ts*/$a <=> $b;

  $previous = $scalar_func(firstx($vec));
  foreach ($vec as $next) {
    $next = $scalar_func($next);
    if ($comparator($next, $previous) < 0) {
      return false;
    }
    $previous = $next;
  }

  return true;
}