{
  my @list;

  sub set {
    $_ = shift @list
      for @_;
  }

  sub from (&$){
    my ($c_list,$c_loop) = @_;
    @list= $c_list->();
  LOOP:
    while (@list) { 
      $c_loop->();
    }
  }

  sub loop (&){
    $_[0]
  }
  
}

sub xlast{
  no warnings 'exiting';
  last LOOP;
}