[xsl] flat list of contents and for-each-group

[Stanislav Pejša <standap@xxxxxxxxx>]

Hello,
I have problem with converting a part of an XML file into more 
hierarchically structured XML.

My guess is that multilevel grouping with each-for-group is the method I 
should use, but I tried several methods - group-by, group-starting-with, 
and group-adjacent and it worked partially. The first "Chapter" level 
works as it should, but can't process the lower levels. I want to 
replicate the sequence in the list, but I want the output to be properly 
nested.

The other problem is that for some files the string will start with 
letter, sometime with a number, e.g. Part 1; A/1; 1/7). I tried to use 
regular expressions by they did not work.

Thanks in advance,
Standa

my input xml file looks like this:

<book>
  <title>SomeTitle</title>
  <description>SomeDescription</description>
  <b_part><level_name>Chapter I: Title of Chapter I</level_name></b_part>
  <b_part><level_name>Section 1: Title of section 1</level_name></b_part>
  <b_part><level_name>Part 1: Title of Part 1</level_name></b_part>
  <b_part><level_name>Part 2: Title of Part 2</level_name></b_part>
  <b_part><level_name>Part n: Title of Part n </level_name></b_part>
  <b_part><level_name>Section 2: Title of Part 2</level_name></b_part>
  <b_part><level_name>Part 1: Title of Part 1</level_name></b_part>
  <b_part><level_name>Part n: Title of Part n</level_name></b_part>
  <b_part><level_name>Chapter II: Title of Chapter II</level_name></b_part>
  <b_part><level_name>A) Title of Section A</level_name></b_part>
  <b_part><level_name>A/1 Title of Part 1</level_name></b_part>
  <b_part><level_name>A/n Title of Part n</level_name></b_part>
  <b_part><level_name>B) Title of Section A</level_name></b_part>
  <b_part><level_name>B/1 Title of Part 1</level_name></b_part>
  <b_part><level_name>B/n Title of Part n</level_name></b_part>
</book>


my stylesheet:

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"; 
xmlns:xs="http://www.w3.org/2001/XMLSchema"; version="2.0">
  <xsl:output method="xml" encoding="UTF-8" name="xml" indent="yes"/>
  <xsl:template match="/">
    <book>
      <xsl:apply-templates select="book"/>
    </book>
  </xsl:template>
  <xsl:template match="book">
    <xsl:for-each select="./title">
      <title>
        <xsl:value-of select="."/>
      </title>
    </xsl:for-each>
    <xsl:if test="b_part">
      <xsl:call-template name="toc_xml"/>
    </xsl:if>
  </xsl:template>

  <xsl:template name="toc_xml">
    <toc>
      <p>Table of contents</p>
      <xsl:for-each-group select="b_part" 
group-by="./level_name[starts-with(.,'Chapter')]">
        <xsl:call-template name="level-01"/>
      </xsl:for-each-group>
    </toc>
  </xsl:template>
  <xsl:template name="level-01">
    <chapter>
      <title>
        <xsl:value-of select="./level_name"/>
      </title>
      <xsl:for-each-group select="current-group() except ." 
group-starting-with="b_part/level_name[starts-with(.,'Section')]">
        <xsl:call-template name="level-02"/>
      </xsl:for-each-group>
    </chapter>
  </xsl:template>
  <xsl:template name="level-02">
    <section>
      <title>
        <xsl:value-of select="./level_name"/>
      </title>
      <xsl:for-each-group select="current-group() except ." 
group-starting-with="b_part/level_name[starts-with(.,'[A-Z]/[0-9]')]">
        <xsl:call-template name="level-03"/>
      </xsl:for-each-group>
    </section>
  </xsl:template>
  <xsl:template name="level-03">
    <part>
      <title>
        <xsl:value-of select="./level_name"/>
      </title>
    </part>
  </xsl:template>
</xsl:stylesheet>

desired output:

<book>
  <title>Some title</title>

  <toc> <p>paragraph</p>
  <chapter><title>Chapter I: Title of Chapter I</title>
  <section><title>Section 1: Title of Section 1</title>
  <part><title>Part 1: Title of Part 1</title></part>
    <part><title>Part 2: Title of Part 2</title></part>
   <part><title>Part n: Title of Part n</title></part>
  </section>
   <section><title>Section 2: Title of Section 2</title></section>
    <part><title>Part 1: Title of Part 1</title></part>
    <part><title>Part n: Title of Part n</title></part>
  </chapter>
   <chapter><title>Chapter II: Title of Chapter II</title>
 <section><title>A) Title of Section A</title>
 <part><title>A/1 Title of Part 1</title></part>
 <part><title>A/n Title of Part n </title></part>
</section>
   <section><title>B) Title of Section B</title>
    <part><title>B/1 Title of Part 1</title></part>
 <part><title>B/n Title of Part n </title></part>
   </section>
   </chapter>
  </toc>>
</book>