Re: [xsl] complex positioning problem

Subject: Re: [xsl] complex positioning problem
From: Bruce D'Arcus <bdarcus@xxxxxxxxxxxxx>
Date: Tue, 2 Nov 2004 19:23:14 -0500
Hi Geert,

On Nov 2, 2004, at 6:02 PM, Geert Josten wrote:

Here's the second issue I've no clue how to solve (beyond Wendell's suggestion about using temporary trees). I assume I may want to somehow create a virtual element in the temporary tree that indicates the position of the unique linkend value in the document (and between citations), but I'm not really sure.

The traffic on this list is quite high, but I believe your question is still open.

Yup, still open.


Wendell noted correctly that your input document doesn't cover all situations. Even more, I think it is just not complex enough for the general problem of numbering citations.

I'm afraid it's going to have to be.


BTW, I'm using XSLT 2.0 (I should have stated that again), and my strategy has been to create a temporary tree with enhanced data that I use for subsequent processing.

Current code is here:

http://www.users.muohio.edu/darcusb/files/xbiblio.tar.gz

Some considerations:
- the bibliographic information is presumably unordered and is often sorted and numbered in the order that the biblio_refs_ occur.

Yes.


- the id's in your sample give an impression of the position, but this impression is false

How so?


Puzzling on the problem, I came up with some steps to tackle this. I'll try to explain...

Consider the following scenario (the dots represent ordinary text):
  ...........ref b, ref a.......
  .......ref a, ref b...........
  a) author xx, book yy
  b) author zz, website blabla

I think this should be presented like:
  ...........[1,2].......
  .......[2,1]...........
  1] author zz, website blabla
  2] author xx, book yy

Or prehaps one would like the [2,1] to be presented like [1,2] as well..

There are two ways to order numbered citations. One is based on occurrence within the document (e.g. the biblioref elements), and the other is to sort the bibliography as you would in an author-year style, number those, and then use them in the citation. This is an absolutely silly style that results in markers like [34, 2] and [1, 23], but it should be that hard I guess because I already the author-year style working fine.


First of all, the bibliorefs have to be gathered. I did this with an index (xsl:key). After that, the bibliorefs have to be uniquefied to be able to get the position of the first of each distinct biblioref. I gather the unique list in a global variable, which has to be accessed through a node-set function in XSLT 1 (other solutions would be too complex to explain, putting aside maintenance). The detemination of the position is done in a template.

It is probably not the most efficient code, but it works.

This is what I wondered about; particularly whether there are some new functions in XSLT 2.0 that would get me the functionality I need, as well as decent performance.


Note also that I didn't solve the ordering of the bibliorefs within one citation. That can be done, by gathering the positions in a variable again and doing the sorting magic as you like.

XSLT 2.0 grouping can handle that.


Anyway, let me see if I understand what you've done conceptually....

  <xsl:key name="bibrefs" match="d:biblioref" use="'all'" />
  <xsl:key name="bibrefs" match="d:biblioref" use="@linkend" />
  <xsl:key name="biblio" match="d:mods" use="@ID" />

OK, use keys to index the biblioref elements. I don't really have experience with using keys, so wasn't sure if I needed them, or how to use them here. One thing to note is that the biblioref elements can be all over the document: at various levels of section depth, or in footnotes, for example.


<xsl:variable name="unique-bibrefs">
<xsl:for-each select="key('bibrefs', 'all')">
<xsl:if test="generate-id(.) = generate-id(key('bibrefs', @linkend)[1])">

What is the above doing?


        <xsl:copy-of select="." />
      </xsl:if>
    </xsl:for-each>
  </xsl:variable>

<!--+ ==============================================================
    | default templates
    +-->

  <xsl:template match="/">
    <bibrefs>
      <xsl:for-each select="key('bibrefs', 'all')">
        <xsl:copy-of select="." />
      </xsl:for-each>
    </bibrefs>
    <unique-bibrefs>
      <xsl:copy-of select="$unique-bibrefs" />
    </unique-bibrefs>
    <xsl:apply-templates select="node()"/>
  </xsl:template>

And the above?


  <xsl:template match="d:biblioref" mode="get-bibref-position">
    <xsl:variable name="linkend" select="@linkend" />
    <xsl:for-each select="msxsl:node-set($unique-bibrefs)/*">
      <xsl:if test="@linkend = $linkend">
        <xsl:value-of select="position()" />
      </xsl:if>
    </xsl:for-each>
  </xsl:template>

I'm not quite following this either.


Bruce

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