[XML-SIG] XSLT sorting by "authors" element, with multiple authors

[Uche Ogbuji]

> "Jon Berry" <jberry at sandia.gov> writes:
> | 
> | I'd like to sort by the last name, alphabetically by
> | first differing author.  So the algorithm would be:
> |     * within each article, sort authors by lastname
> |     * to compare Article A with Article B:
> |               * Look at last names of first author (if different, 
> | comparison done)
> |               * else if first authors are the same, look at second authors,
> |               * etc.
> |               * if not distinguished, go on to next sorting key (say 
> | 'title')
> | 
> | Noting of course that we might be comparing articles with
> | different numbers of authors.  
> | 
> | In initial searches, it looked like the   xsl:for-each-group
> | and/or xsl:function constructs might help, but they don't seem
> | to be supported by the current PyXML/4Suite implementations.
> | 
> | So, with the constraint that I'm trying to avoid buying a book for now,
> | is this doable using templates, easy, and currently implementable
> | with free software?
> 
> I believe that using extension functions is a good approach to
> cope with your problem.
> 
> The primary cause of your problem is that the xsl:sort looks at
> only the value of the first node, instead of all the selected
> nodes.  For example, the following xsl:sort element selects all
> the last names of an article's authors, but only the first last
> name is used as a sort key.
> 
> <xsl:sort select="authors/person/@lastname" order="ascending" />
> 
> So, a simple solution is to change this behavior of xsl:sort by
> defining an extension function like this:
> 
> <xsl:sort select="ext:strings(authors/person/@lastname)" order="ascending" />
> 
> where the extension function ext:strings() can be defined, for
> example, as follows:
> 
> def strings(context, nodeset):
>     return "".join(map(lambda x: x.nodeValue, nodeset))
> 
> It seems very Pythonic, doesn't it? :-)  See documentation for
> more information on extension functions in Python.

Just being helpful:

http://uche.ogbuji.net/tech/akara/nodes/2003-01-01/xslt-ext-funcs


-- 
Uche Ogbuji                                    Fourthought, Inc.
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