XSLT: can we use abs value ?

Question

Hi guys,

I would like to know if in XLST can we use the math:abs(...) ? I saw this somewhere but it does not work . I have something like:

<tag>
  <xsl:value-of select="./product/blablaPath"/>
</tag>

I tried to do something like:

<tag>
  <xsl:value-of select="math:abs(./product/blablaPath)"/>
</tag>

but does not work.

Any ideas? Thanks.

Corneliu.

Answer 1

math:abs is not built in to XSLT or XPATH. It is an XSLT extension, provided by the runtime you are transforming with.

Here is an article about .NET xslt extensions.

Here is one for Java (Xalan).

Answer 2

abs() is trivial enough. Implemented in pure XSLT it would look like this:

<xsl:template name="abs">
  <xsl:param name="number">

  <xsl:choose>
    <xsl:when test="$number &gt;= 0">
      <xsl:value-of select="$number" />
    <xsl:when>
    <xsl:otherwise>
      <xsl:value-of select="$number * -1" />
    </xsl:otherwise>
  </xsl:if>
</xsl:template>

in your context you would invoke it like this:

<tag>
  <xsl:call-template name="abs">
    <xsl:with-param name="number" select="number(product/blablaPath)" />
  </xsl:call-template>
</tag>

Answer 3

Here is a single XPath expression implementing the abs() function:

($x >= 0)*$x - not($x >= 0)*$x

This evaluates to abs($x).