Err, isn't a texinfo file already a TeX file? (He says to TeXnician Karl
:)
Sure, but it wouldn't work to do:
... (la)tex stuff ...
\input texinfo.tex
... texinfo stuff ...
... more (la)tex stuff ...
The definitions in texinfo.tex will certainly screw up anything
following -- the parsing is completely different, starting with a
different escape character (@ instead of \). You can't just put the
texinfo stuff in a group because there are tons of global definitions
(and need to be).
latex and texinfo will certainly collide too, so that's out.
I've never actually tried making a document with just plain tex stuff
before, and then read texinfo.tex in the middle. I imagine the page
numbers, at least, would be messed up, but it might ultimately be
workable. I rather suspect the OP was thinking latex though.
Cheers,
karl