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

[Adam Retter]

Any chance you could offer me an example? ;-)

On 26 January 2016 at 16:40, W.S. Hager <wshager at gmail.com> wrote:
> Hi Adam,
>
> Perhaps it helps to start with rewriting the xpath expressions as pure
> lambda expressions. Maybe that way you could apply lambda calculus?
>
> Cheers,
> Wouter
>
> 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
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>
>
>
>
> --
>
> W.S. Hager
> Lagua Web Solutions
> http://lagua.nl



-- 
Adam Retter

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http://www.adamretter.org.uk