Re: n squared behavior with XT for 'preceding' tests?

["G. Ken Holman" <gkholman@xxxxxxxxxxxxxxxxxxxx>]

At 99/07/22 09:30 +0000, Sebastian Rahtz wrote:
>David Carlisle writes:
> > I less wisely did:
>
>thank goodness you don't need any sleep, is all I can say. But I am
>very happy to see the result, even if I am noty sure entirely why it
>works... perhaps we need the Holman Annotation.

:{)}

I can't always take the time to do this, but I always enjoy learning from
David.

The annotated version is below.

I hope this helps.

................ Ken

T:\FTEMP>type test.xml
<math>

<mrow>
<mi>a</mi><mi>b</mi><mi>c</mi><mn>1</mn>
<mi>x</mi><mi>y</mi><mi>z</mi><mn>2</mn>
</mrow>

</math>

T:\FTEMP>type test.xsl
<!--XSL stylesheet by David Carlisle; annotations by G. Ken Holman-->
<xsl:stylesheet xmlns:xsl="http://www.w3.org/XSL/Transform/1.0";
                default-space="strip"
                indent-result="yes">

                    <!--for everything that isn't special, just copy it-->
<xsl:template match="*" >
<xsl:copy>
     <xsl:apply-templates/>
</xsl:copy>
</xsl:template>
         
       <!--this element needs to be coagulated with following adjacents-->
<xsl:template match="mi">                    
         <!--if this is the first in a run of adjacents, handle the run-->
<xsl:if test="not(from-preceding-siblings(*[position()=1 and  
                                            from-self(mi)]))">
     <xsl:apply-templates mode="grab" select="."/>
</xsl:if>
      <!--otherwise, this isn't the first, so it must have been handled-->
</xsl:template>

  <!--walk along adjacent elements of same name, tracking concatenation-->
<xsl:template mode="grab" match="mi">
<xsl:param-variable name="x" expr="''"/>    <!--first time around empty-->
<xsl:choose>
  <xsl:when test="from-following-siblings(*[position()=1 and 
                                            from-self(mi)])">   
                 <!--there are more where this came from, keep grabbing-->
     <xsl:apply-templates mode="grab" 
                          select="from-following-siblings(*[1])">
       <xsl:param name="x" expr="concat($x,.)"/>      <!--result so far-->
     </xsl:apply-templates>
   </xsl:when>
   <xsl:otherwise>
              <!--we have reached the end of a grouping, put out result-->
     <mi><xsl:value-of select="concat($x,.)"/></mi>
   </xsl:otherwise>
</xsl:choose>
</xsl:template>
</xsl:stylesheet>

T:\FTEMP>call xsl test.xml test.xsl testout.xml
T:\FTEMP>type testout.xml
<math>
<mrow>
<mi>abc</mi>
<mn>1</mn>
<mi>xyz</mi>
<mn>2</mn>
</mrow>
</math>

T:\FTEMP>

--
G. Ken Holman                    mailto:gkholman@xxxxxxxxxxxxxxxxxxxx
Crane Softwrights Ltd.             http://www.CraneSoftwrights.com/s/
Box 266, Kars, Ontario CANADA K0A-2E0   +1(613)489-0999   (Fax:-0995)
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