[xsl] Yet Another Sorting Problem

[Allin Cottrell <cottrell@xxxxxxx>]

I've consulted the FAQ, but I'm having difficulty extrapolating to the 
answer to this one.

In sorting a bibliography, I want to sort the elements (e.g. books, 
articles) by author's name and publication date.  OK, that's easy. 
My problem is handling multiple authors, with the the number unknown 
in advance.  For flexibility in formatting the authors' names I can't 
have them all in one big string; the data-structure I actually have is 
this:

* each bibliography-entry element has an "authorlist" element.
* an authorlist has one or more "author" elements, which have
  attributes such as surname, fist name, initials.

The easy solution, if it were available, would be to wrap the xsl:sort 
selection code in an xsl:for-each ranging across the authors in an 
entry's authorlist, but that's forbidden by xsl syntax.

Next thought: construct on the fly a "grand author string" by lumping 
together the names and initials of all the authors in an entry's 
authorlist, and use this as the sort key for the entries.

Seems promising, but I haven't managed to implement it.  What I have 
so far is broken -- I realize I can't use xsl:attribute to do this, 
but I'm not sure what I should be using.

<xsl:template match="bibliography">
  <xsl:for-each select="book|journalarticle|paper">
    <xsl:attribute name="auhash">
      <xsl:for-each select="authorlist/author">
        <xsl:value-of select="@surname"/>
        <xsl:value-of select="@initials"/>
      </xsl:for-each>
    </xsl:attribute>
  </xsl:for-each>
  <xsl:apply-templates select="book|journalarticle|paper">
    <xsl:sort select="@auhash"/>
    <xsl:sort select="pubdate"/>
  </xsl:apply-templates>
</xsl:template>

--
Allin Cottrell
Department of Economics
Wake Forest University, NC