<!ELEMENT vform (field+)>
<!ATTLIST vform name CDATA #IMPLIED>

<!ELEMENT field (rules, message)>
<!ATTLIST field name CDATA #REQUIRED>
<!ATTLIST field optional (true|false) "false">
<!ATTLIST field xml (true|false) "false">

<!ELEMENT rules (rule*)>
<!ELEMENT rule (#PCDATA)>
<!ATTLIST rule name CDATA #REQUIRED>

<!ELEMENT message (#PCDATA)>