I have a straight TeX document, and I'd like to produce from it a Texinfo document. Does there exist a tool that does this, or a set of guidelines? TeX and Texinfo seem to be closely related, so it feels like it should be possible, but I can't seem to find anything that does this conversion in particular.
If there is no general tool for that, how much information am I likely to lose in going from TeX to XML to Texinfo?
The document in question is the TeX source of the Mongrel2 manual, for reference - so it's a non-trivial chunk of TeX, but also guaranteed not to be a malformed or perverse chunk of TeX.