package Validate; # use package to declare a module

sub validate_date {
    my $val = shift;
    return() unless 
        $val =~ /^(\d{2})-(\d{2})-(\d{4})$/;
    return "$3-$1-$2";
}

sub validate_time {
    my $val = shift;
    return() unless 
        $val =~ /^(\d{2}):(\d{2}) (am|pm)$/i;
    return uc("$1:$2 $3");
}

1;


##</code><code>##

#!/usr/bin/perl -w
#would use -wT in production to check for taint

print "Content-type: text/plain\n\n";

use strict;
use CGI::Carp qw(fatalsToBrowser); # only for development
use Validate;

my $date = "12-01-2003";
my $time = "12:23 pm";   # would come from user input and so needs to untainted

my $valid_date = Validate::validate_date( $date );

if ( $valid_date ) {
    print "$valid_date is okay\n";
}
else {
    print "$date is invalid\n";
}

my $valid_time = Validate::validate_time( $time );

if ( $valid_time ) {
    print "$valid_time is okay\n";
}
else {
    print "$time is invalid\n";
}

exit;