Re: [xsl] XPath for expressing contiguous elements?

["Dimitre Novatchev dnovatchev@xxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

Here is one without any negation:

/*/A[preceding-sibling::A][following-sibling::A]
           [preceding-sibling::*[1][self::A]]
           [following-sibling::*[1][self::A]]
and true()


On Mon, May 1, 2017 at 7:21 AM, Michael Kay mike@xxxxxxxxxxxx
<xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
> not(*[not(self::A)][following-sibling::A][preceding-sibling::A])
>
> returns true if and only if there is no non-A element that is both preceded and followed by an A element, which I think is equivalent to your expression and rather simpler.
>
> Michael Kay
> Saxonica
>
>
>> On 1 May 2017, at 14:00, Costello, Roger L. costello@xxxxxxxxx <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>>
>> Hi Folks,
>>
>> I want an XPath expression that implements this rule:
>>
>>       All <A> elements shall be contiguous within <Test>.
>>
>> In this example all A's are contiguous, so the rule is satisfied:
>>
>> <Test>
>>    <B/>
>>    <A/>
>>    <A/>
>>    <A/>
>>    <B/>
>> </Test>
>>
>> In this example there is an intervening B, so the rule is not satisfied:
>>
>> <Test>
>>    <B/>
>>    <A/>
>>    <A/>
>>    <B/>
>>    <A/>
>>    <B/>
>> </Test>
>>
>> Below is the XPath that I created. I have two questions about it:
>>
>> (1) Is it correct? Do you see anything it would fail to catch?
>>
>> (2) Is there a better (simpler, more efficient) XPath expression?
>>
>> Here is the XPath (within a Schematron rule):
>>
>> <sch:rule context="Test">
>>    <sch:assert test="
>>        every $i in A satisfies
>>           (if ($i/preceding-sibling::A) then $i/preceding-sibling::*[1][self::A] else true())
>>           and
>>           (if ($i/following-sibling::A) then $i/following-sibling::*[1][self::A] else true())
>>        ">
>>        All A's shall be contiguous within Test.
>>    </sch:assert>
>> </sch:rule>
>>
> 



-- 
Cheers,
Dimitre Novatchev
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