The IRIS regex functionality is built on the ICU engine, which was based on (but does not rigorously adhere to) PCRE. This includes the ObjectScript $MATCH() and $LOCATE() functions as well as the %Regex.Matcher class. A web search turns up a handful of articles and posts discussing the differences between the two.

Python has a PCRE library (python-pcre) that may help if your development effort can be transitioned in whole or part to Python.

Found the SequenceNumber Property property. Just what I needed needed!

for i = 1:1:count {w cdef.Properties.GetAt(i).Name_"|"_cdef.Properties.GetAt(i).Parameters.GetAt("MAXLEN")_"|"_cdef.Properties.GetAt(i).SequenceNumber,!}

Thanks, this is useful @Nick Petrocelli! It appears that the order in which the properties are returned by iterating with Count() is sorted alphabetically. Is there any way to fetch them in the order in which they were defined in the class? I have SqlColumnNumber assigned for each of the properties, so if there's a way to fetch that keyword's value I can order them according to that. I'd prefer not to hard-code them in if possible, as the spec may change ...

Thanks!