Re: [xslt] floating point conversion

[Nick Wellnhofer <wellnhofer aevum de>]

On 10/09/10 18:26, Phil Shafer wrote:
> I'm looking into an issue with floating point rounding, and
> have hit an issue with number conversion.
>
> The crux is that number("100.15") is not equal to 100.15.

That's how floating point numbers work.

> % cat /tmp/test.xslt
> <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
> <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"; version="1.0">
>    <xsl:output method="xml" indent="yes"/>
>    <xsl:template match="/">
>      <op-script-results>
>        <output>
>          <xsl:value-of select="format-number('100.15', '####.################')"/>
>        </output>
>        <output>
>          <xsl:value-of select="format-number(100.15, '####.################')"/>
>        </output>
>        <output>
>          <xsl:value-of select="format-number(number('100.15') , '####.################')"/>
>        </output>
>      </op-script-results>
>    </xsl:template>
> </xsl:stylesheet>
> % xsltproc /tmp/test.xslt /tmp/test.xml
> <?xml version="1.0"?>
> <op-script-results>
>    <output>100.1500000000000057</output>
>    <output>100.1499999999999915</output>
>    <output>100.1500000000000057</output>
> </op-script-results>
>
> % xsltproc --version
> Using libxml 20707, libxslt 10126 and libexslt 815
> xsltproc was compiled against libxml 20707, libxslt 10126 and libexslt 815
> libxslt 10126 was compiled against libxml 20707
> libexslt 815 was compiled against libxml 20707
>
> Can anyone point me in the right direction for tracking this down?

That the second number is different seems to be a bug in libxml2. The 
implementations of xmlXPathStringEvalNumber and xmlXPathCompNumber are 
slightly different AFAICS.

Nick