XPath version

At the face-to-face, we've been discussing the issue of XPath 1.0 vs
XPath 2.0.

Michael Kay pushed back, other commenters have pushed back, and the
XSL WG has pushed back on our decision to require XPath 1.0.

So, suppose we don't require it?

Suppose instead we say that an implementation may use XPath 1.0 or
XPath 2.0 at its option. For the vast majority of XPath expressions
that are actually used in XProc, it won't make any difference.

If a pipeline that uses an XPath 2.0 expression is passed to a
processor that only understands XPath 1.0, the user loses. This is a
practical interoperability problem today, but we expect over the long
term that XPath 2 will replace XPath 1 and so the interoperability
problem will become more and more theoretical over time.

We add a note that says "for maximum interoperability, pipeline
authors SHOULD restrict themselves to expressions that are the same in
all versions of XPath".

I think we'd still leave the issue of type support implementation defined.

                                        Be seeing you,
                                          norm

-- 
Norman Walsh <ndw@nwalsh.com> | Everything should be made as simple as
http://nwalsh.com/            | possible, but no simpler.