@tubetime I worked on some error messages last week, for unrelated reasons - PTAL at Github latest & I'll fix anything missing.

Docs: I love writing docs, but don't know what people need, so let me know.

Equation reduction is tempting. I was thinking of writing something like a cupl2pld stage so that the pld format remains WYSIWYG. It's lower priority than just making it more usable in its basic form, though.

Thanks for the feedback. If GitHub issues work better for you, that's also good.