Re: [xsl] Seek an XPath 2.0 expression for checking that each object in a file system has one parent

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

  count(//*[starts-with(name(), 'F')])
eq
  count(distinct-values(//*[starts-with(name(), 'F')]/name()))


This is just a first try. There could be even a shorter expression.


Cheers,
Dimitre.

On Sun, Oct 16, 2016 at 4:29 PM, G. Ken Holman g.ken.holman@xxxxxxxxx
<xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx> wrote:
> I see that you are dealing with only the names of the grandchildren of the
> root.  The vollowing has three solutions, one based on the names (as you
> have done) and two that are namespace-safe.  The latter two are equivalent,
> but since the operators "every" and "some" didn't come to mind for you, I
> thought I would illustrate both.
>
> The second two work with axes the way you were getting started.  But for the
> first I think you can rephrase your problem to be not that all elements have
> one parent but that there is only one of every element ... which I think is
> equivalent given the limited amount of information regarding your objective.
>
> I hope this helps.
>
> . . . . . . Ken
>
> ~/t/ftemp $ cat roger1.xml
> <?xml version="1.0" encoding="UTF-8"?>
> <Root>
>     <D1>
>         <D2/>
>         <F1/>
>     </D1>
>     <D2>
>         <F2/>
>     </D2>
> </Root>
> ~/t/ftemp $ cat roger2.xml
> <?xml version="1.0" encoding="UTF-8"?>
> <Root>
>     <D1>
>         <D2/>
>         <F1/>
>     </D1>
>     <D2>
>         <F2/>
>         <F1/>
>     </D2>
> </Root>
> ~/t/ftemp $ xslt2 roger1.xml roger.xsl
> true
> true
> true
> ~/t/ftemp $ xslt2 roger2.xml roger.xsl
> false
> false
> false
> ~/t/ftemp $ cat roger.xsl
> <?xml version="1.0" encoding="UTF-8"?>
> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
>   xmlns:xs="http://www.w3.org/2001/XMLSchema";
>   exclude-result-prefixes="xs"
>   version="2.0">
>
> <xsl:output method="text"/>
>
> <xsl:template match="/">
>   <xsl:value-of select="
>     count(/Root/*/*)=count(distinct-values(/Root/*/*/name(.)))"/>
>   <xsl:text>&#xa;</xsl:text>
>   <xsl:value-of select="
>     every $elem in /Root/*/* satisfies
>           not($elem/following::*[not(*)]/node-name(.)=node-name($elem))"/>
>   <xsl:text>&#xa;</xsl:text>
>   <xsl:value-of select="
>     not( some $elem in /Root/*/* satisfies
>               $elem/following::*[not(*)]/node-name(.)=node-name($elem))"/>
>   <xsl:text>&#xa;</xsl:text>
> </xsl:template>
>
> </xsl:stylesheet>
> ~/t/ftemp $
>
>
>
> At 2016-10-16 22:33 +0000, Costello, Roger L. costello@xxxxxxxxx wrote:
>>
>> Hi Folks,
>>
>> I am modeling a file system. Below is a sample instance. D1 means
>> Directory 1, F1 means File 1, etc. The instance says this: the content of
>> directory 1 is directory 2 and file 1. The content of directory 2 is file 2.
>> Stated another way, directory 2 and file 1 are contained in directory 1, and
>> file 2 is contained in directory 2.
>>
>> <Root>
>>     <D1>
>>         <D2/>
>>         <F1/>
>>     </D1>
>>     <D2>
>>         <F2/>
>>     </D2>
>> </Root>
>>
>> I want an XPath 2.0 expression which returns true if each object has one
>> parent. An "object" is a directory or a file. In the example above each
>> object has one parent, so the XPath should return true. Below is an illegal
>> file system because F1 has two parents: D1 and D2.
>>
>> <Root>
>>     <D1>
>>         <D2/>
>>         <F1/>
>>     </D1>
>>     <D2>
>>         <F2/>
>>         <F1/>
>>     </D2>
>> </Root>
>>
>> The XPath should return false.
>>
>> This XPath is almost correct:
>>
>> for $i in /Root/* return for $j in $i/* return not(name($j) =
>> $i/following-sibling::*/*/name())
>>
>> I say it is "almost" correct because it returns multiple Booleans, not a
>> single Boolean result.
>>
>> Two Questions:
>>
>> 1. What is the correct XPath expression?
>> 2. Is there a different way to model in XML a file system that would
>> enable a simple XPath expression?
>>
>> /Roger
>
>
>
> --
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>
> 



-- 
Cheers,
Dimitre Novatchev
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