XML/XSLT stylesheet/number function

Convert char and boolean to number

File: Data.xml

File: Transform.xslt
<?xml version="1.0"?>
<xsl:stylesheet version="2.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:xs="http://www.w3.org/2001/XMLSchema">
  <xsl:output method="text"/>
  <xsl:template match="/">
    <xsl:text>Tests of addition in XPath 2.0&#xA;</xsl:text>
    <xsl:text>&#xA;  9 + 3 = </xsl:text>
    <xsl:value-of select="9 + 3"/>
    <xsl:text>&#xA;  9 + 3.8 = </xsl:text>
    <xsl:value-of select="9 + 3.8"/>
    <xsl:text>&#xA;  9 + number("4") = </xsl:text>
    <xsl:value-of select="9 + "4"" version="1.0"/>
    <xsl:text>&#xA;  9 + number("Q") = </xsl:text>
    <xsl:value-of select="9 + number("Q")"/>
    <xsl:text>&#xA;  9 + number(true()) = </xsl:text>
    <xsl:value-of select="9 + number(true())"/>
    <xsl:text>&#xA;  9 + number(false()) = </xsl:text>
    <xsl:value-of select="9 + number(false())"/>
  </xsl:template>
</xsl:stylesheet>

Output:
Tests of addition in XPath 2.0
  9 + 3 = 12
  9 + 3.8 = 12.8
  9 + number("4") = 13
  9 + number("Q") = NaN
  9 + number(true()) = 10
  9 + number(false()) = 9