<?xml version='1.0'?>
<!DOCTYPE xsl:stylesheet SYSTEM "file:///C:/C64/home/ht/lib/xml/xsl.dtd" >
<xsl:stylesheet xmlns:e="http://markup.co.uk/excel" xmlns:xs="http://www.w3.org/2001/XMLSchema" version="3.0">
  <xsl:function name="e:a2n" as="xs:integer">
  <!-- Convert an alphabetic excel column 'index' into a number,
       a sort of base 26 + 1, since 'A' is 1 and 'AA' is 27 -->
  <xsl:param name="aa" as="xs:string"/>
  <xsl:value-of select="let $l := string-length($aa),
                        $lv := string-to-codepoints(substring($aa,$l))-$codeBase
                        return if ($l=1) then $lv
                               else $lv+(26*e:a2n(substring($aa,1,$l - 1)))"/>
 </xsl:function>
</xsl:stylesheet>