Re: XQuery issue regarding creating table of contents(TOC) dynamically.

[G. Ken Holman]

At 2010-01-07 11:28 +0530, anuj kumar wrote:
>I have an xml of the form
>...
>A change in the designator(Designators may be in alpha, numeric, 
>roman, alpha-numeric,
>etc bounded or unbounded by brackets) format must be used as basis 
>for identifying the primary level.

I've implemented this so you can use regular expressions to determine 
the level indications.

>Designators in sequence or series must be treated as primary level 
>text of the same level. For example:
>(a)-first level
>(b)-first level
>(c)-first level
>
>I have to create the following output xml out of the above input xml:
>...
>Pleae advise, how to do this?

You don't share with us what you have tried and what has not worked for you.

I have a complete solution below.  I found it easier to think first 
in XSLT because of the grouping facilities that are available, and 
then to just transliterate that into XQuery for a pure-XQuery solution.

Note that readers may find it interesting to have to do the following 
in XQuery:

   (<tree>{elements-expression}</tree>)/*

... in order to create a sibling relationship between a copy of nodes 
so that the recursive use of the following-sibling axis would not 
access the original nodes.  Simply referencing the nodes isn't 
sufficient because the nodes retain their original location in the 
original tree.

I hope this helps.

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


T:\ftemp>type anuj.xml
<doc>
   <p>(a)- first level </p>
   <p>(1)- second level</p>
   <p>(2)- second level</p>
   <p>(A)- third level</p>
   <p>(B)- third level</p>
   <p>(3)- second level</p>
   <p>(b)- first level</p>
</doc>
T:\ftemp>call xslt2 anuj.xml anuj.xsl
<?xml version="1.0" encoding="UTF-8"?>
<doc>
    <parent>
       <title>(a)- first level </title>
       <child>
          <title>(1)- second level</title>
       </child>
       <child>
          <title>(2)- second level</title>
          <child>
             <title>(A)- third level</title>
          </child>
          <child>
             <title>(B)- third level</title>
          </child>
       </child>
       <child>
          <title>(3)- second level</title>
       </child>
    </parent>
    <parent>
       <title>(b)- first level</title>
    </parent>
</doc>
T:\ftemp>call xquery anuj.xq
<?xml version="1.0" encoding="UTF-8"?>
<doc>
    <parent>
       <title>(a)- first level </title>
       <child>
          <title>(1)- second level</title>
       </child>
       <child>
          <title>(2)- second level</title>
          <child>
             <title>(A)- third level</title>
          </child>
          <child>
             <title>(B)- third level</title>
          </child>
       </child>
       <child>
          <title>(3)- second level</title>
       </child>
    </parent>
    <parent>
       <title>(b)- first level</title>
    </parent>
</doc>
T:\ftemp>type anuj.xsl
<?xml version="1.0" encoding="US-ASCII"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                 version="2.0">

<xsl:output indent="yes"/>

<xsl:variable name="patterns" as="element(patterns)">
   <patterns>
     <pattern>^\([a-z]\)</pattern>
     <pattern>^\([\d+]\)</pattern>
     <pattern>^\([A-Z]\)</pattern>
   </patterns>
</xsl:variable>

<xsl:template match="doc">
   <doc>
     <xsl:call-template name="parent">
       <xsl:with-param name="population" select="p"/>
       <xsl:with-param name="pattern" select="$patterns/pattern[1]"/>
       <xsl:with-param name="relationship" select="'parent'"/>
     </xsl:call-template>
   </doc>
</xsl:template>

<xsl:template name="parent">
   <xsl:param name="population"/>
   <xsl:param name="pattern"/>
   <xsl:param name="relationship"/>
   <xsl:if test="$population">
     <!--only do something if there is something to do-->
     <xsl:choose>
       <xsl:when test="not($pattern)">
         <!--no more depth-->
         <xsl:for-each select="$population">
           <xsl:element name="{$relationship}">
             <title><xsl:copy-of select="node()"/></title>
           </xsl:element>
         </xsl:for-each>
       </xsl:when>
       <xsl:otherwise>
         <!--process next level of depth-->
         <xsl:for-each-group select="$population"
                             group-starting-with="*[matches(.,$pattern)]">
           <xsl:element name="{$relationship}">
             <title><xsl:copy-of select="node()"/></title>
             <xsl:call-template name="parent">
               <xsl:with-param name="population"
                               select="current-group()[position()>1]"/>
               <xsl:with-param name="pattern"
                               select="$pattern/following-sibling::*[1]"/>
               <xsl:with-param name="relationship" select="'child'"/>
             </xsl:call-template>
           </xsl:element>
         </xsl:for-each-group>
       </xsl:otherwise>
     </xsl:choose>
   </xsl:if>
</xsl:template>

</xsl:stylesheet>

T:\ftemp>type anuj.xq
declare namespace a = "urn:X-anuj";

declare variable $patterns as element(patterns) :=
   <patterns>
     <pattern>^\([a-z]\)</pattern>
     <pattern>^\([\d+]\)</pattern>
     <pattern>^\([A-Z]\)</pattern>
   </patterns>;

declare function a:parent( $population, $pattern, $relationship )
{
   if( $population )
   then
     (: only do something if there is something to do :)
     if( not($pattern) )
     then
       (: no more depth :)
       for $each in $population return
         element {$relationship} {<title>{$each/node()}</title>}
     else
       (: process next level of depth :)
       for $level in $population[matches(.,$pattern)]
       return
         element {$relationship}
         {
           <title>{$level/node()}</title>,
           a:parent( (<tree>
                       {$level/following-sibling::* except
                        $level/following-sibling::*[matches(.,$pattern)][1]/
                                               (self::* | 
following-sibling::* )
                       }
                      </tree>)/* (:create a new tree of children:),
                      $pattern/following-sibling::*[1] (:the next pattern:),
                      'child' )
         }
   else ()
};

<doc>{a:parent( doc('anuj.xml')/doc/p, $patterns/pattern[1], 'parent' )}</doc>


T:\ftemp>rem Done!


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