XPath

TODO

The xpath parser (mechanism/notation/xpath.scm) does not yet fit to the SXPath engine in mechanism/tree.scm. Two reasons: a) the parser provides more information than SXPath can deal with, b) see the SXML mailing list, I remember a problem, where SXPath can't deal some namespace problem c) maybe it's not really desirable, those DSSSL function are much more efficient.

http://www.w3.org/TR/2003/WD-xquery-semantics-20030822/

The implementation is still sketchy/prototypical because it was intented to use the same evaluator as for the (also sketchy) XSLT implemenation. However that requires some query rewriting (as reported to be detailed in http://www.pms.informatik.uni-muenchen.de/publikationen/PMS-FB/PMS-FB-2004-1.pdf - 2004-05-07 file missing on server). It appears to be the case that not all xpath queries can be rewritten in a forward only style, therefore we will likely need two distinct evaluators.