xsl-list
[Top] [All Lists]

Re: [xsl] Problems grouping nested items within a completely flat structure

2014-08-07 08:50:43
Heiko,

thanks for your approach. While this helped me to grasp the grouping concept in 
XSLT 2.0 a little bit better (but only a little bit), I noticed that your 
solution is specifically tailored to the exact sequence of nodes that I used in 
the example file. But, unfortunately, life doesn't work that way:-) If, e.g. I 
put the first para[@pgftag='Body text'] down to right after the note, the 
stylesheet yields:

<book>
   <chapter>
      <title>Introduction</title>
      <p>Display the online help as follows:</p>
      <ul>
         <li>Display the online help as follows:</li>
         <ul>
            <li>To view the help for a panel, press the help (PF1) key.</li>
         </ul>
      </ul>
      <p>This chapter expains...</p>
      <ul>
         <li>To view the help for an input field or select a parameter from a 
pop-up window, press PF1.</li>
         <li>Check relevant sections of <em>XXXX</em>.</li>
         <li>Visit our web site to get...</li>
      </ul>
[...]

Clearly not what is intended. So what is the right strategy to solve this in a 
generic way? Sure, you'd want to group all sibling elements to chapter as long 
as they are not indicating a new chapter or a subdivision. But then? You cannot 
go for a group like

      <xsl:for-each-group group-starting-with="para[@pgftag eq 'Body text']" 
select="current-group() except .">
        <p>
          <xsl:apply-templates select="*"/>
        </p>
        <ul>
          <xsl:apply-templates select="."/>
        </ul>
      </xsl:for-each-group>

when you don't know what first child element you have. Instead, I'd imagine 
templates that can match single paras and don't need no know about their 
context (like para[@pgftag='Body text'] or para[@pgftag='Note']. But as soon as 
you have list structures I currently don't see a solution that goes beyond 
grouping consecutive list items and if something like a note drops in, you have 
to regard the following list item as the first item of a new list.
And here I'm back to square one. I cannot e.g. use

      <xsl:for-each-group group-starting-with="para[@pgftag eq 'Bullet text']" 
select="current-group() except .">

within the chapter template, since I don't know if and when such a list can be 
expected, so to me it looks more like:

  <xsl:template match="para[@pgftag='Chapter']">
        <chapter><title><xsl:apply-templates/></title>
          <xsl:apply-templates select="all siblings that are in the same 
chapter until a subdivision comes up"/>
        </chapter>
   </xsl:template>

   <xsl:template match="para[@pgftag='Bulleted text'][1]">
      <ul>
         <xsl:for-each-group select="following-sibling::*" 
group-adjacent="name()">
        <xsl:apply-templates select="." mode="listitem"/>
          </xsl:for-each-group>
      </ul>
   </xsl:template>

But Saxon doesn't like that for-each-group and complains: "the only axes 
allowed in a pattern are the child and attribute axes".
To complicate matters, subdivisions like '1st Section', ..., '4th Section' may 
be nested, so a chapter may consist either of simple content, as shown here, or 
some overview, followed by one or more subsections...
From what I've seen so far, I cannot deduce a generic solution to my problem. 
Probably I'm still missing something elementary here...

Thanks so far,
Frank


-----Original Message-----
From: Heiko Niemann kontakt(_at_)heiko-niemann(_dot_)de 
[mailto:xsl-list-service(_at_)lists(_dot_)mulberrytech(_dot_)com]
Sent: Mittwoch, 6. August 2014 18:09
To: xsl-list(_at_)lists(_dot_)mulberrytech(_dot_)com
Subject: Re: [xsl] Problems grouping nested items within a completely flat 
structure

Hi,

this should get you close to the desired result. Just add more templates 
necessary.

Regards,
Heiko



<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
version="2.0">
  <xsl:output method="xml" encoding="UTF-8"/>

  <xsl:template match="/textflow">
    <book>
      <xsl:for-each-group select="para" group-starting-with="para[@pgftag eq 
'Chapter']">
        <xsl:apply-templates select="."/>
      </xsl:for-each-group>
    </book>
  </xsl:template>

  <xsl:template match="para[@pgftag eq 'Chapter']">
    <chapter>
      <title>
        <xsl:apply-templates select="*"/>
      </title>
      <xsl:for-each-group group-starting-with="para[@pgftag eq 'Body text']" 
select="current-group() except .">
        <p>
          <xsl:apply-templates select="*"/>
        </p>
        <ul>
          <xsl:apply-templates select="."/>
        </ul>
      </xsl:for-each-group>
    </chapter>
  </xsl:template>

  <xsl:template match="para[@pgftag eq 'Body text']">
    <xsl:for-each-group group-starting-with="para[@pgftag = ('Bulleted text', 
'Note')]" select="current-group() except .">
      <xsl:apply-templates select="."/>
    </xsl:for-each-group>
  </xsl:template>

  <xsl:template match="para[@pgftag eq 'Bulleted text']">
    <li>
      <xsl:apply-templates select="*"/>
    </li>
    <xsl:if test="count(current-group()) &gt; 1">
      <ul>
        <xsl:for-each-group select="current-group() except ."
group-starting-with="para[@pgftag eq 'Bullet sub']">
          <xsl:apply-templates select="."/>
        </xsl:for-each-group>
      </ul>
    </xsl:if>
  </xsl:template>

  <xsl:template match="para[@pgftag eq 'Bullet sub']">
    <li>
      <xsl:apply-templates select="*"/>
    </li>
  </xsl:template>

  <xsl:template match="para[@pgftag eq 'Note']">
    <note>
      <xsl:apply-templates select="*"/>
    </note>
  </xsl:template>

  <xsl:template match="paraline|xref">
    <xsl:apply-templates/>
  </xsl:template>

  <xsl:template match="render">
    <xsl:choose>
      <xsl:when test="@charformat eq 'Emphasis'">
        <em>
          <xsl:value-of select="."/>
        </em>
      </xsl:when>
      <xsl:when test="@charformat eq 'Bold'">
        <b>
          <xsl:value-of select="."/>
        </b>
      </xsl:when>
      <xsl:otherwise>
        <xsl:value-of select="."/>
      </xsl:otherwise>
    </xsl:choose>
  </xsl:template>

  <!--next template for testing purposes only-->
  <xsl:template match="*">
    <bah/>
  </xsl:template>

</xsl:stylesheet>




Hi.

While there is a lot of information about grouping available, I still
have problems applying it to my particular case of a document-centric XML 
file.
Obviously I haven’t yet understood it fully.

This is my (redacted) source. Please excuse its length, but this
better illustrates my problem. I use Saxon 9HE, but I am open to both,
XSL 1.0 or
2.0 solutions.

      <textflow tftag=”A”>
         <para pgftag=”Chapter”>
            <paraline>Introduction</paraline>
         </para>
         <para pgftag="Body text">
            <paraline>This chapter expains...</paraline>
         </para>
         <para pgftag="Bulleted text">
            <paraline>Display the online help as follows:</paraline>
         </para>
         <para pgftag="Bullet sub">
            <paraline>To view the help for a panel, press the help
(PF1) key.</paraline>
         </para>
         <para pgftag="Bullet sub">
            <paraline>To view the help for an input field or select a
parameter from a pop-up window, </paraline>
            <paraline>press PF1.</paraline>
         </para>
         <para pgftag="Note">
            <paraline>If you do not specify a required parameter, or
enter an incorrect one, XXXX </paraline>
            <paraline>will prompt you for the correct
information.</paraline>
         </para>
         <para pgftag="Bulleted text">
            <paraline>Check relevant sections of <render
charformat="Emphasis">XXXX</render>.</paraline>
         </para>
         <para pgftag="Bulleted text">
            <paraline>Visit our web site to get...</paraline>
         </para>
         <para pgftag="Body text">
            <paraline>The topics covered are:</paraline>
         </para>
         <para pgftag="Bulleted text">
            <paraline>
               <xref srctext="55167: 1st Section: What is
XXX?"><render charformat="Bold">What is XXX?</render></xref>
            </paraline>
         </para>
         <para pgftag="Bulleted text">
            <paraline>
               <xref srctext="55167: 1st Section: How Does XXX
Work?"><render charformat="Bold"> How Does XXX Work?</render></xref>
            </paraline>
         </para>
         <para pgftag=”Chapter”>
            <paraline>Next chapter</paraline>
         </para>
     </textflow>

The idea is, quite obviously, grouping the relevant list items, so
you’d end up (ideally!) with something like e.g.:

<book>
  <chapter>
     <title>Introduction</title>
     <p>This chapter explains...</p>
     <ul>
        <li>Display the online help as follows:</li>
        <ul>
           <li>To view the help for a panel, press the help (PF1)
key.</li>
           <li>To view the help for an input field or select a
parameter from a pop-up window, press PF1.</li>
       </ul>
        <note> If you do not specify a required parameter, or enter an
incorrect one, XXXX will prompt you for the correct
information.</note>
        <li>Check relevant sections of <em>XXXX</em>.</li>
        <li>Visit our web site to get ...</li>
     </ul>
     <p> The topics covered are:</p>
     <ul>
        <li><b>What is XXX?</b></li>
        <li><b>How Does XXX Work?</b></li>
     </ul>
   </chapter>
  <chapter>
     <title>Next chapter</title>
  </chapter>
</book>


As you can see, the source is a completely flat, linear sequence from
which I have to establish every kind of structure. Therefore, I use
something like

<xsl:template match=”textflow”>
  <book><xsl:apply-templates/></book>
</xsl:template>

<xsl:template match=”para[@pgftag=’Chapter’]”>
    <xsl:variable name="chapter-id" select="generate-id()"/>
    <chapter>
       <title><xsl:apply-templates/></title>
         <xsl:apply-templates
select="following-sibling::*[not(self::*[@pgftag='Chapter'])]

[generate-id(preceding-sibling::para[@pgftag='Chapter'][1])
= $chapter-id]"/>
    </chapter>
</xsl:template>

<xsl:template match=”para[@pgftag=’Bulleted text’]”>...

That is, I can’t imagine having a single template matching textflow
in which I apply <xsl:for-each-group> for all kinds of different paras.
Instead, I use Muenchian grouping (yep, starting with XSL 1.0, but now
I use 2.0), but ran into serious recursion trouble when fiddling with
nested chapter and list structures.
The other principal problem is how to decide when a structure has
ended, because all elements are on the same sibling axis. Now, a
chapter ends, when another <para pgftag=’Chapter’> or some <para
pgftag=’Appendix’> appears. But there is no way to decide when the
first bulleted list in the example really ends, since the list items
may include other elements such as notes or nested lists. You could
only use criteria such as “This list has ended, when the next paragraph is 
e.g.
<para @pgftag=’Body text’> or <para @pgftag=’Chapter’>
appears”.

Now, if anyone could point me in the right direction, I’d be very
grateful, since it’s bugging me for some time now. And, please
apologize the length...

Thank you,
Frank


Software AG – Sitz/Registered office: Uhlandstraße 12, 64297
Darmstadt, Germany – Registergericht/Commercial register: Darmstadt
HRB 1562 - Vorstand/Management Board: Karl-Heinz Streibich
(Vorsitzender/Chairman), Dr. Wolfram Jost, Arnd Zinnhardt; -
Aufsichtsratsvorsitzender/Chairman of the Supervisory Board: Dr.
Andreas Bereczky - http://www.softwareag.com




Software AG – Sitz/Registered office: Uhlandstraße 12, 64297 Darmstadt, Germany 
– Registergericht/Commercial register: Darmstadt HRB 1562 - Vorstand/Management 
Board: Karl-Heinz Streibich (Vorsitzender/Chairman), Dr. Wolfram Jost, Arnd 
Zinnhardt; - Aufsichtsratsvorsitzender/Chairman of the Supervisory Board: Dr. 
Andreas Bereczky - http://www.softwareag.com

--~----------------------------------------------------------------
XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list
EasyUnsubscribe: http://lists.mulberrytech.com/unsub/xsl-list/1167547
or by email: xsl-list-unsub(_at_)lists(_dot_)mulberrytech(_dot_)com
--~--

<Prev in Thread] Current Thread [Next in Thread>