package Chatbot::Eliza::Polite;use Chatbot::Eliza;use vars '@ISA';# file: Chatbot/Eliza/Polite.pm# Figure 12.3:  Eliza::Chatbot::Polite module@ISA = 'Chatbot::Eliza';# return our welcome linesub welcome {  my $self = shift;  $self->botprompt($self->name . ":\t");  # Set Eliza's prompt   $self->userprompt("you:\t");            # Set user's prompt  # Generate the initial greeting  return join ('',               $self->botprompt,               $self->{initial}->[ int rand scalar @{ $self->{initial} } ],"\n",               $self->userprompt);}# Return the response to a line of user inputsub one_line {  my $self = shift;  my $in = shift;  my $reply;  # If the user wants to quit,  # print out a farewell and quit.  if ( $self->_testquit($in) ) {    $reply = $self->{final}->[ int rand scalar @{ $self->{final} } ];    $self->{_quit}++;  # flag that we're done    return $reply . "\n";  }  # Invoke the transform method  # to generate a reply.  $reply = $self->transform( $in );  return join ('',               $self->botprompt,               $reply,"\n",               $self->userprompt);}# Return true if the session is donesub done { return shift->{_quit} }1;