[xquery-talk] Function for determining one XPath as subset of another

W.S. Hager wshager at gmail.com
Tue Jan 26 08:40:52 PST 2016

Hi Adam,

Perhaps it helps to start with rewriting the xpath expressions as pure
lambda expressions. Maybe that way you could apply lambda calculus?


2016-01-26 17:26 GMT+01:00 Adam Retter <adam.retter at googlemail.com>:

> Given two simple XPaths, say:
> 1. //w
> 2. /x/y/z/w[@a = 'v']
> As a human I can very easily tell without evaluating the expressions
> that (2) will return a subset (or the same set) of the results that
> (1) would return *should* they both be evaluated.
> My goal here is given any two simple arbitrary XPaths expressed as
> strings, and without evaluating them against a context, to determine
> whether one would return a subset of the results of the other.
> I wondered if there might be an algorithm or library that someone
> already had or has written which might be able to give me the answer?
> I realise that I can only probably cover a subset of XPath itself, but
> it is only the path steps with predicates which I am interested in.
> Ideally I am looking for something in Java.
> --
> Adam Retter
> skype: adam.retter
> tweet: adamretter
> http://www.adamretter.org.uk
> _______________________________________________
> talk at x-query.com
> http://x-query.com/mailman/listinfo/talk


W.S. Hager
Lagua Web Solutions
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://x-query.com/pipermail/talk/attachments/20160126/1e03e69c/attachment.html>

More information about the talk mailing list