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Re: [xsl] compare two node sets

2020-01-21 09:42:08
Hi,

Another solution not yet suggested in this thread is to avoid deep-equal() and 
rely on a signature function.

So for example,

<xsl:function name="f:signature" as="xs:string">
  <xsl:param name="who" as="node()"/>
  <xsl:value-of select="string-join($who/(first, last), ' ')"/>
</xsl:function>


Then your list of author-directors is 
//author[f:signature(.)=parent::film/child::director/f:signature(.)]

(Or the other way around.)

Wrap the expression in the filter in not() to retrieve authors who did not 
direct, etc.

One advantage of this approach is it's easy to adjust the signature logic to 
real-world exigencies.

Cheers, Wendell

-----Original Message-----
From: Wolfhart Totschnig wolfhart(_dot_)totschnig(_at_)mail(_dot_)udp(_dot_)cl 
<xsl-list-service(_at_)lists(_dot_)mulberrytech(_dot_)com> 
Sent: Sunday, January 19, 2020 4:22 PM
To: xsl-list(_at_)lists(_dot_)mulberrytech(_dot_)com
Subject: Re: [xsl] compare two node sets

Thank you, David, Michael, and Liam for the prompt replies! Michael's solution 
seems to be the simplest to implement. I use Saxon 9 HE, so XPath 2.0 should be 
okay. And, indeed, quadratic performance should not be an issue. However, Saxon 
throws the following error:

XPST0003: Unexpected token "every" at start of expression

Is there a typo in the expression? I used the expression as given:

<xsl:when test="count(//director) eq count(//author) and every $d in //director 
satisfies some $a in //author satisfies deep-equal($d/*, $a/*)">

To clarify, the context node is the <film> element.

Wolfhart


On 19.01.20 17:55, Liam R. E. Quin liam(_at_)fromoldbooks(_dot_)org wrote:
On Sun, 2020-01-19 at 20:37 +0000, Wolfhart Totschnig 
wolfhart(_dot_)totschnig(_at_)mail(_dot_)udp(_dot_)cl wrote:
Hello,

I have an XSL/XPath problem to which I cannot find the solution. I 
have an xml file with data about films, in the following form
(simplified):

[..]
. By contrast, in the following example the test should return 
<false>:

     <film>
        <title>M</title>
        <director>
           <first>Fritz</first>
           <last>Lang</last>
        </director>
        <author>
           <first>Thea von</first>
           <last>Harbou</last>
        </author>
        <author>
           <first>Fritz</first>
           <last>Lang</last>
        </author>
     </film>
Why?

As stated,
  <xsl:mode on-no-match="shallow-copy" />

   <xsl:template match="/">
     <xsl:apply-templates select="/films/film[
         some $a in author satisfies
         (
             ($a/first = director/first)
             and ($a/last = director/last)
         )
     ]"/>
   </xsl:template>

Liam


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