I meant to send this comment earlier in the day, I hope it is still useful:

FRAGMENT - not complete:
    my ($results, $err_page) = $self->check_rm('qs_display',
        {
            required => [qw/upfirstname uplastname upemail upusername 
+uppassword confirm_password/],
            optional => [qw/upzip upcountry/],
            filters => ['trim'],
            constraints => {
                uppassword => {
                    #Make sure passwords are the same
                    name => 'user_passwords',
                    constraint => \&check_password,
                    params => [qw(uppassword confirm_password)],
                },
                upusername => {
                    #Is username unique?
                    name => 'user_username',
                    constraint => \&check_username,
                    params => [qw(upusername)],
                },
                upemail => 'email',
                upzip => 'zip_or_postcode',
            },
            msgs => {
                any_errors => 'err__',
                prefix => 'err_',
                constraints => {
                    'user_passwords' => "Your passwords don't match",
                    'user_username' => "Username not unique",
                },
            },
        } );
        return $err_page if $err_page;
        # Results are valid
        my $dfv_results = $results->valid();
        print STDERR Dumper( $dfv_results );
        $self->header_type('redirect');
        $self->header_props( -url => 'http://posiedon.mine.nu');
        return;
}


sub check_password {
    my ($p1, $p2) = @_;
    
    if ($p1 eq $p2) {
        return 1;
    } else {
        return 0;
    }
}
[download]

I think it is pretty straightforward. I get the two passowrd values from my form, the trivial sub (which could be much simplified!) merely returns true or false. I am using D::FV 3.14 with CGI::Application

The code is not original, Cees Hek gave me the outline in an answer to a question on the CGI::App mail list.

jdtoronto