Hi, one thing I like about groff/troff is the ability to quickly write preprocessors extending troff. I wrote one as part of SciTECO -- in the SciTECO language: https://github.com/rhaberkorn/sciteco/blob/master/doc/htbl.tes (Note: contains control codes not properly displayed by Github) It's a "drop-in" replacement for tbl, that emits HTML tables for processing with grohtml. The code is horrible (it was hacked interactively and then turned into a batch script), and it only supports a subset of tbl, that is exactly what I used in the SciTECO manpage tables. It can be seen in action here: http://rhaberkorn.github.io/sciteco/manuals/sciteco.7.html
I've also written a small preprocessor in csnobol4 that pipes .HIGHLIGHT blocks in your groff -mom code through GNU source-highlight, effectively giving you syntax highlighting for inline code blocks and an UML preprocessor that pipes .UML blocks into PlantUML and inserts .PDF_IMAGE references in its place. Anyone interested in these? Best regards, Robin