sub query {
   my ($str,@argv) = @_;
   my $answer;

   while (1) {
      print "$str ", $argv[0] ? "[$argv[0]]: " : ": ";
      chomp($answer = <STDIN>);
      last unless @argv;
      last if grep $answer =~ /^\Q$_\E$/i, @argv;
   }
   return $answer;
}