I thought that this was interesting to share.
Recently an XSLT user discussed a problem on xsl-list, which was solved by Jeni Tennison using XSLT 1.0 long time ago.
I presented a XSLT 2.0 solution for the same problem. The 2.0 solution is lot shorter as compared to the 1.0 solution, and utilizes the XSLT 2.0 instruction, xsl:analyze-string.
The link to this thread is at, http://www.biglist.com/lists/lists.mulberrytech.com/xsl-list/archives/200808/msg00383.html.
This problem could be a nice use case for xsl:analyze-string instruction.