use Loop::Watch;

my $temp = 20;  # celsius, that is

# doing { ... } does *not* loop
ensure { $temp >= 0 } watching($temp), doing {
  move_to_florida();
  wait_until_winter();
  move_to_new_jersey();
  wait_until_spring();
  move_to_montana();
  wait_until_fall();
  move_to_alaska();
  wait_until_winter();
};