use Time::HiRes qw(usleep);
my $PROMPT="What's the ticket number?\n";
my $TRY_AGAIN_PROMPT="excuse me?\n";


my $TICKET_NUMBER=prompt_until($PROMPT,
                               $TRY_AGAIN_PROMPT,
                               '^\d{7}$|^NOTICKET$',
                               1500);

sub prompt_until {
 my $prompt_text=$_[0];
 my $try_again_prompt=($_[1])? $_[1] : '';
 my $until_regex=($_[2])? $_[2] : '.*';
 my $speed=($_[3])? $_[3] : '0';
 my $answer;

 if ($speed) {
  print_slow($prompt_text,$speed);
 }
 else {
  print "$prompt_text";
 }
 $answer=<STDIN>;
 until ($answer=~m/$until_regex/) {
  if ($speed) {
   print_slow($try_again_prompt,$speed);
  }
  else {
   print "$try_again_prompt";
  }
  $answer=<STDIN>;
 }
 chomp $answer;
 return $answer;
}
################################################################################

sub print_slow {
 my $speed=pop(@_);
 my $phrase=join('',@_);
 my @characters=split(//,$phrase);
 foreach my $char (@characters) {
  print $char;
  usleep($speed);
 }
}
################################################################################