Re: [xsl] XPath expression to check that there are no intervening elements?

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

To avoid the false true when there are no Bs at all:


XPath 1.0:
B and not(B[1]/following-sibling::node()[not(position()  >
../count(B))][not(self::B)])


XPath 2.0:
B and not(node()[. >> ../B[1] and . << ../B[last()]][not(self::B)])

On Tue, Jul 19, 2016 at 9:29 AM, Dimitre Novatchev <dnovatchev@xxxxxxxxx> wrote:
> XPath 1.0:
>
>  not(B[1]/following-sibling::node()[not(position() >
> ../count(B))][not(self::B)])
>
> XPath 2.0:
>
> not(node()[. >> ../B[1] and . << ../B[last()]][not(self::B)])
>
> Cheers,
> Dimitre
>
> On Tue, Jul 19, 2016 at 9:16 AM, G. Ken Holman g.ken.holman@xxxxxxxxx
> <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
>> I like Mike's answer for XSLT 2.
>>
>> Your XSLT 1 solution can be improved by reducing the number of counting
>> actions.  Your solution has three uses of count() ... this has only two:
>>
>>   count(B[last()]/preceding-sibling::*[not(self::B)]) =
>>   count(B[1]/preceding-sibling::*[not(self::B)])
>>
>> Avoiding the use of counting you could do the following:
>>
>>   string( generate-id( B[1]/preceding-sibling::*[not(self::B)][1] ) ) =
>>   string( generate-id( B[last()]/preceding-sibling::*[not(self::B)][1] ) )
>>
>> The use of string() is necessary in case the sequence of children starts
>> with B.
>>
>> Come to think of it, neither your answer, Mike's answer nor my answer will
>> work if there are no B children at all.  You will get a false positive.
>> Does your test need to accommodate that situation?
>>
>> . . . . . . . . Ken
>>
>> At 2016-07-19 15:44 +0000, Costello, Roger L. costello@xxxxxxxxx wrote:
>>>
>>> Hi Folks,
>>>
>>> This XML has a solid block of <B> elements:
>>>
>>> <Document>
>>>     <A/>
>>>     <B/>
>>>     <B/>
>>> </Document>
>>>
>>> This XML has an intervening <C> element:
>>>
>>> <Document>
>>>     <A/>
>>>     <B/>
>>>     <C/>
>>>     <B/>
>>> </Document>
>>>
>>> I need an XPath expression to return a Boolean value:
>>>
>>>         Return true if there is one solid block of <B> elements
>>>                 (no intervening elements).
>>>         Otherwise, return false.
>>>
>>> I created a horrendous XPath expression to solve it:
>>>
>>> count(B) eq (B[last()]/count(preceding-sibling::*)+1 -
>>> B[1]/count(preceding-sibling::*))
>>>
>>> Can you provide a better (simpler, more efficient) XPath expression?
>>>
>>> /Roger
>>>
>>
>>
>> --
>> Check our site for free XML, XSLT, XSL-FO and UBL developer resources |
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>> G Ken Holman _ _ _ _ _ _ _ _ _ _ mailto:gkholman@xxxxxxxxxxxxxxxxxxxx |
>> Google+ blog _ _ _ _ _ http://plus.google.com/+GKenHolman-Crane/posts |
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>>
>>
>> ---
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>> 
>
>
>
> --
> Cheers,
> Dimitre Novatchev
> ---------------------------------------
> Truly great madness cannot be achieved without significant intelligence.
> ---------------------------------------
> To invent, you need a good imagination and a pile of junk
> -------------------------------------
> Never fight an inanimate object
> -------------------------------------
> To avoid situations in which you might make mistakes may be the
> biggest mistake of all
> ------------------------------------
> Quality means doing it right when no one is looking.
> -------------------------------------
> You've achieved success in your field when you don't know whether what
> you're doing is work or play
> -------------------------------------
> To achieve the impossible dream, try going to sleep.
> -------------------------------------
> Facts do not cease to exist because they are ignored.
> -------------------------------------
> Typing monkeys will write all Shakespeare's works in 200yrs.Will they
> write all patents, too? :)
> -------------------------------------
> Sanity is madness put to good use.
> -------------------------------------
> I finally figured out the only reason to be alive is to enjoy it.



-- 
Cheers,
Dimitre Novatchev
---------------------------------------
Truly great madness cannot be achieved without significant intelligence.
---------------------------------------
To invent, you need a good imagination and a pile of junk
-------------------------------------
Never fight an inanimate object
-------------------------------------
To avoid situations in which you might make mistakes may be the
biggest mistake of all
------------------------------------
Quality means doing it right when no one is looking.
-------------------------------------
You've achieved success in your field when you don't know whether what
you're doing is work or play
-------------------------------------
To achieve the impossible dream, try going to sleep.
-------------------------------------
Facts do not cease to exist because they are ignored.
-------------------------------------
Typing monkeys will write all Shakespeare's works in 200yrs.Will they
write all patents, too? :)
-------------------------------------
Sanity is madness put to good use.
-------------------------------------
I finally figured out the only reason to be alive is to enjoy it.