use Term::ReadLine;
  my $term = Term::ReadLine->new('Simple Perl calc');
  my $prompt = "Enter your arithmetic expression: ";
  my $OUT = $term->OUT || \*STDOUT;
  while ( defined ($_ = $term->readline($prompt)) ) {
    my $res = eval($_);
    warn $@ if $@;
    print $OUT $res, "\n" unless $@;
    $term->addhistory($_) if /\S/;
  }