parsing version number strings

Has anyone out there come up with a method to parse an arbitrary version
number string in an XSLT for numeric comparison?

For example, I'm parsing some Doxygen output and I need to apply different
templates based on which version of Doxygen produced the output. For
example, I have something that needs to be applied only to versions 1.3.4
and older.

The version of Doxygen is stored in an attribute of the root <doxygen>
element: <doxygen version="1.3.4">

Here is a sequence of increasingly newer version numbers that illustrates
some of the complexities of parsing this string:

1.2.9
1.2.10
1.2.10.1
1.3
1.3.1
1.3.2
1.3.2.1

There doesn't seem to be an XPath function that gives me the position of a
character within a string, which kind of hamstrings me, as far as I can
tell.

Anyone solved this problem before?

thanks
Ed

Ed Owen
Project Manager
Information Design and Development (IDD)
Sony Computer Entertainment America
e-mail: ed_owen@xxxxxxxxxxxxxxxxxxxx