Re: [xsl] XPath / XSLT 2.1 - Rounding algorithms

["G. Ken Holman" <gkholman@xxxxxxxxxxxxxxxxxxxx>]

At 2008-11-13 16:57 -0500, Rushforth, Peter wrote:
> A couple of years ago, I ran into a need to call extension functions
> to round numbers in the "traditional" way: to round half up for results of
> .5 (or more).  I found that it was only possible with XSLT to round 
> to the even
> number.

Not sure where you read that ... the round() function goes to the 
nearest whole number or does a ceiling() for the value "x.5":

  http://www.w3.org/TR/2007/REC-xpath-functions-20070123/#func-round

> Specifically, round-half-up(decimal_num,num_digits), where 'up' means towards
> positive or negative infinity, is what I'm looking for.

Except for the number of digits you could do:

  if( x < 0 ) then -( round(abs(x)) ) else round(x)

... and use format-number() to handle the digits bit.

I hope the example below helps.

. . . . . . . . . Ken

T:\ftemp>type peter.xsl
<?xml version="1.0" encoding="US-ASCII"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
                xmlns:xsd="http://www.w3.org/2001/XMLSchema";
                xmlns:c="urn:X-Crane"
                exclude-result-prefixes="xsd c"
                version="2.0">

<xsl:output method="text"/>

<xsl:template match="/">
-2.5: <xsl:value-of select="c:PeterRound(-2.5)"/>
2.5:  <xsl:value-of select="c:PeterRound(2.5)"/>
</xsl:template>

<xsl:function name="c:PeterRound">
  <xsl:param name="x"/>
  <xsl:sequence select="if( $x &lt; 0 ) then -( round(abs($x)) )
                                        else round($x)"/>
</xsl:function>

</xsl:stylesheet>
T:\ftemp>xslt2 peter.xsl peter.xsl con

-2.5: -3
2.5:  3
T:\ftemp>

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