time    # with no args, command means "show time"
 time arg [...]   # with args, it means "set time"

##</code><code>##

while (<STDIN>) {
    my ( $cmd, @args ) = split;
    if ( exists( $command{$cmd} )) {
        $command{$cmd}->( @args );
    else {
        $command{default}->();
    }
}

##</code><code>##

my %command = (
    time => sub {
        if ( @_ == 0 ) {
            print "time is ", scalar localtime, $/;
        } else {
            print "let's pretend the time is @_\n";
        }
      },
    date => sub {
        if ( @_ == 0 ) {
            print "You don't have a date for tonight\n";
        } else {
            print "Okay, we'll see if @_ will go out with you\n";
        }
      },
#  ... and so on (updated to remove undeclared array)
);