Saxon has a built-in collation option which will handle such sort keys
directly:

<xsl:sort select="..."
collation="http://saxon.sf.net/collation?alphanumeric=yes"

It's product-dependent, of course, but it might save you some work.

Michael Kay
http://www.saxonica.com/ 

> -----Original Message-----
> From: Yves Forkl [mailto:Y.Forkl@xxxxxx] 
> Sent: 25 July 2006 10:43
> To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> Subject:  Creating a padded sort key: easier from elt 
> sequence or string?
> 
> Hi,
> 
> I'm lucky to be able to define some XML structure largely 
> according to the needs of (XSLT) processing.
> 
> I have strings of variable length consisting of numbers and 
> letters separated by dots, like "3.11.A.9" or "3.2.B.7".
> 
> Each of these strings shall take the role of a value for a 
> sort key, but only after padding each number with sufficient 
> zeros in order to sort "3.11.A.9" after and not before 
> "3.2.B.7" (then "3.02.B.7"). The letters are always single 
> letters, and the numbers have no more than 3 digits.
> 
> My question is as follows: which XML representation is more 
> convenient when trying to fulfil this task in XSLT 1.1?
> 
> 1) a PCDATA element containing a string like the ones above
> 
> 2) an element containing a sequence of PCDATA elements, one 
> for each of the numbers and letters (the dot in between may 
> be added during processing)
> 
> And what's the best way of going about implementing the 
> creation of the padded sort keys in XSLT from the more 
> favorable representation? Would the solution differ much in XSLT 2.0?
> 
> Any hints are very much appreciated.
> 
>   Yves