[xsl] Function that reduces the number of digits to the right of the decimal point?

["Roger L Costello costello@xxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

Hi Folks,

$num is a variable holding a decimal value.

$desired-number-of-digits-after-decimal-point is a variable holding an integer
value.

I want a function that reduces the number of digits to the right of the
decimal point in $num according to the value specified in
$desired-number-of-digits-after-decimal-point

Example #1:
$num = 42.366978
$desired-number-of-digits-after-decimal-point = 2
The result of applying the function is: 42.36

Example #2:
$num = 42.366978
$desired-number-of-digits-after-decimal-point = 0
The result of applying the function is: 42

Below is one way to implement the function. Is there a better way? By "better"
I mean simpler, more correct.

Also, is there a better name for the function?  By "better" I mean shorter,
more standardized. /Roger
-----------------------------------------------------
<xsl:function name="f:reduce-number-of-digits-after-decimal-point"
as="xs:string">
    <xsl:param name="num" as="xs:string" />
    <xsl:param name="desired-number-of-digits-after-decimal-point"
as="xs:integer" />

    <xsl:variable name="whole-part" select="substring-before($num, '.')"/>
    <xsl:variable name="fraction-part" select="substring-after($num, '.')"/>
    <xsl:variable name="reduced-fraction-part"
select="substring($fraction-part, 1,
$desired-number-of-digits-after-decimal-point)"/>
    <xsl:choose>
        <xsl:when test="$desired-number-of-digits-after-decimal-point gt 0">
            <xsl:value-of select="concat($whole-part, '.',
$reduced-fraction-part)"/>
        </xsl:when>
        <xsl:otherwise>
            <xsl:value-of select="$whole-part"/>
        </xsl:otherwise>
    </xsl:choose>
</xsl:function>