[luatex] Newbie question: how to stop TeX trying to interpret Lua?

[Dirk Laurie]

I've managed quite well for several months by writing and debugging 
my Lua code separately and using only "dofile" inside \directlua.
Now I'm trying to do it all inside LuaTeX.

It comes as a shock that

\directlua{ tex.print("\\TeX") }

does not work.  TeX grabs the double-quote and tries to make some
accented character.  I've read to about page 25 of the LuaTeX manual
and it's already way over my head.  The answer, apart from working
with dofile, may be in there but I'm not going to find it soon.

Help please!

Dirk