The Usage Guideline Editor allows the formalization of a field/element format as an XML Pattern. These XML patterns are Regular Expression such as defined by the W3C in the XML Schema standard. The full and official definition of this Regular Expression language, by W3C, can be found here.
Each programming language defines its own implementation of Regular Expressions which differs slightly from language to language. MyStandards will only recognize patterns compliant with the W3C specification of Regular Expressions defined in the XML Schema standard.
Additional examples can be found on the following links :
Examples
[A-Za-z]{9,9} : Exactly 9 letters (characters between A and Z or a and z)
[0-9]{0,2} : Between 0 and 2 numbers (characters between 0 and 9)
[A-Z]{2,2}|[0-9]{2,2} : Exactly two capital letters or exactly two numbers
[A-Z]{6,6}([0-9]{3,3}){0,1} : Six capital letters followed by 3 optional numbers (either the 3 numbers are present, either none)