Match References, Variables and Fixed Strings

The <group> and <data> elements can reference match groups from parent expressions or from stored matches in variables. In the case of the <group> element, referenced values are passed on to child expressions whereas the <data> element can use match group references for name and value attributes. In the case of both elements the way of specifying references is the same.

Last modified October 6, 2025: Add section on v7.10 upgrade path (dcd5ca1)