I plan to convert the generation program to XSLT in August and early September of 2019.

Right now testing is not performed rigorously enough — while the regular expression is tested against thousands of selectors including the entire W3C test suite, the results are simply checked by human eye. This should be automated. My current thought is to add a selector_is_valid attribute whose value is one of true, false, or (before being verified, or perhaps in some bizarre cases) unknown.^[41]

I plan to present the regular expression itself and the XSLT generation program for it at the TEI Members’ Meeting and Conference in Graz, 2019-09, with the aim of convincing the TEI Consortium to use the regular expression in the TEI schema.