XQuery static typing algorithms?

[Per Bothner]

Is there somewhere a reasonably accessible description of the
tree algorithms needed for XQuery static typing?  I.e. reasonably
readable code (assuming I can study it without legal IP concerns)
or an article?  The Formal Semantics references the 262-page TATA book,
which is more than I'm willing to deal with.

(Not that I have any immediate plans to implement more than
ad hoc static typing for XQuery, but at least it would be nice
to have a road-map, so anything I do is compatible with a real
solution.  Though if the algorithms aren't too complicated, maybe
I'll be inspired ...)
-- 
	--Per Bothner
http://x-query.com/mailman/listinfo/talk   http://per.bothner.com/