Saxon XSLT | Sum Function

Question

Perhaps this was already asked but I haven't been able to locate any posts on this. We use Saxon (HE-9.5.1-2) and the function sum returns a rather unusual value. Sum of 196.30 and 1018.57 is 1214.87 while Saxon returns a value of 1214.8700000000001.

Here's the repro.

Any inputs are appreciated. Thanks.

Answer 1

Use the xs:decimal data type

<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:xs="http://www.w3.org/2001/XMLSchema" exclude-result-prefixes="xs">
    <xsl:output method="xml" encoding="UTF-8" omit-xml-declaration="yes"/>
    <xsl:template match="root">
        <root>
            <xsl:value-of select="sum(item/xs:decimal(.))"/>
        </root>
    </xsl:template>
</xsl:stylesheet>

and you will get e.g. <root>1214.87</root>.

The default number type is IEEE double (xs:double), the same as for instance the number type in JavaScript and for that you will find the same floating point imprecision:

var n1 = 196.30;
var n2 = 1018.57;

var sum = n1 + n2;

console.log(sum);

And of course it is not Saxon specific, any compliant XSLT processor for your code will use double number precision and should give that result.