Even when the W3C promulgates a spec in its final Recommendation form, the spec does not become fixed in stone. Any product expressed in human language always requires further tweaking — filling gaps, fixing ambiguities, and making room for new developments in related specs and technologies. This is the case with the next, still-upcoming version of XPath: Version 2.0.
The XPath 2.0 spec, as of late 2001, still exists in a very tentative state. Not only is it a Working Draft (one of the very first rungs a spec must negotiate on its way up the ladder to full Recommendation status). It’s not yet a specification of syntax, but rather a simple statement of requirements. All you’ll learn from perusing the XPath 2.0 documentation at this point is what XPath 2.0 may ultimately permit you to accomplish — not the specific means you will use to accomplish those ends.
The XPath 2.0 Requirements document explored in this chapter was issued in February, 2001. You can find it on the W3C web site, at http://www.w3.org/TR/xpath20req.
In December 2001, the W3C finally published a Working Draft of the XPath 2.0 spec. In April 2002, this December WD was followed up by another version. This chapter will make occasional reference to this version of the WD as well as the Requirements document.