XSDPattern
Define a regular expression to match. The value has to be serialized or deserialized without any
                error.
- The regular expression is defined in the XML Schema Part 2 specification available here.
 - Backslash characters '\' in a regular expression must be escaped by duplicating it.
 
Example
DEFINE myStr STRING ATTRIBUTES(XSDString, XSDPattern="A.*Z",
  XMLName="MyString")
DEFINE myZipCode INTEGER ATTRIBUTES(XSDInt, XSDPattern="[0-9]{5}",
  XMLName="MyZipCode")
DEFINE myOtherZipCode INTEGER ATTRIBUTES(XSDInt,
 XSDPattern="\\d{5}", XMLName="myOtherZipCode") # regex is \d{5} see note