my $validation_rules = { customer_infos => { optional => [ qw( company fax country ) ], required => [ qw( fullname phone email address city state zipcode ) ], constraints => { email => "email", fax => "american_phone", phone => "american_phone", zipcode => '/^\s*\d{5}(?:[-]\d{4})?\s*$/', state => "state", }, defaults => { country => "USA", }, } };