Learning Perl the right way, part IX:

Task: untaint and validate user input using subroutines in a separate module. Note: Because I eventually want to render the form with HTML::Template, listing the errors, I'm keeping track of the error messages for a <tmpl var> in my form.tmpl template file. So, after I get the data, I pass it, a literal for the error listing, and an array element for the actual message.

Monasterical questions: basically, is this code representative of "good practices" or efficient coding? Specifically, is my scoping, use of variables, passing of data, logic, and structure okay? Other comments? 
use strict;
require "Validate.pm";
use CGI qw(:standard);
new CGI;

my ($name, $phone, $email, $date, @errmsg, $errmsgs);

$name = param('name');
    &val_alpha($name, "Last Name", $errmsg[0]);

$phone = param('phone');
    &val_phone($phone, "Phone Number", $errmsg[1]);

$email = param('email');
    &val_email($email, "E-mail Address", $errmsg[2]);

$date = param('date');
    &val_date($date, "Birth Date", $errmsg[3]);

&error_page(@errmsg);
print "Errors:\n$errmsgs\n";

#handle errors
sub error_page {
    for (@_) {
        if ($_) { $errmsgs .= "$_\n" }
    }
}

$template = HTML::Template->new(filename => "form.tmpl");
$template->param(errors => $errmsgs);

#eventually process and write to the database

__END__

[download]
And for the module: 
#Validate.pm

sub val_alpha {
    if ($_[0] =~ /^([A-Za-z -]*)$/) {
        $_[0] = $1;
    } else {
        $_[2] = "Invalid character(s) in $_[1]";
    }
}

 
sub val_phone {
    if ($_[0] =~ /^[\(]?(\d{3})[\)\.\-]?(\d{3})[\)\.\-]?(\d{4})$/) {
        $_[0] = "$1-$2-$3";
    } else {
        $_[2] = "Invalid $_[1]";
    }
}

sub val_date {
    if ($_[0] =~ /^(\d{2})-(\d{2})-(\d{4})$/) {
        $_[0] = "$1-$2-$3";
    } else {
        $_[2] = "Invalid $_[1]";
    }
}

sub val_email {
    if ($_[0] =~ /^([\w\.\-]{3,})@([\w\.\-]{3,})\.([A-Z]{2,3})$/i) {
        $_[0] = "$1\@$2\.$3";
    } else {
        $_[2] = "Invalid $_[1]";
    }
}

1;

[download]
Thanks all in advance.

—Brad
"A little yeast leavens the whole dough."

In reply to Am I passing and testing user data correctly? by bradcathey

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