I've noticed that grog(1) will suggest options for preprocessors irrespective of whether they're even available on the user's system. Some aren't part of Groff, like grap(1). Others are excluded from certain base installations — Ubuntu Server, for example, ships with pic(1) and tbl(1), but omits chem(1), refer(1) and grn(1). Finally, one of the preprocessors considered by grog while scanning *doesn't even exist*: gideal, hidden behind an undocumented `-J` switch in the main groff(1) executable:
$ groff -J groff: couldn't exec gideal: No such file or directory $ printf 'Foo\n.IS\n.IE\nBar\n' | grog groff -T ps -J -p - It's debatable whether or not Grog should concern itself with site-specific matters like this. After all, an error at the command-line isn't a big deal. Most Troff-savvy users probably have a complete Groff installation on their site anyway. Troff-savviness can be reasonably assumed of anybody running the grog(1) command from their terminal. The problem is when users aren't Troff-savvy, and document formatting is performed by a GUI without user intervention. That's exactly half of what Roff.js <https://github.com/Alhadis/Roff.js> exists to do — the code talking to Groff <https://github.com/Alhadis/Roff.js/blob/8678ef365626e049c58b4ad65d62383fe7db49b9/lib/adapters/troff/groff.mjs> from the browser is substantially more complex than it should be, due to the translation layers involved... So. Thoughts?
