RE: [xsl] tail recursion and NaN

Subject: RE: [xsl] tail recursion and NaN
From: <Jarno.Elovirta@xxxxxxxxx>
Date: Tue, 4 May 2004 08:52:46 +0300
Hi,

> <!--This is the template with recursion to add the prices, 
> needs test for NaN-->
> <xsl:template name="total-value">
>    <xsl:param name="price"/>
>    <xsl:param name="result" select="0"/>
> 	   <xsl:choose>
> 	     <xsl:when test="$price">
> 		<xsl:call-template name="total-value">
> 		   <xsl:with-param name="price" 
> select="$price[position() &gt; 1]"/>
> 		   <xsl:with-param name="result" 
> select="($result + $price)"/>

E.g.Replace this with

  <xsl:with-param name="result">
    <xsl:choose>
      <xsl:when test="string(number($price[1])) = 'NaN'">
        <xsl:value-of select="$result"/>
      </xsl:when>
      <xsl:otherwise>
        <xsl:value-of select="$result + $price[1]"/>
      </xsl:otherwise>
    </xsl:choose>
  </xsl:with-param>

or place the test outside the xsl:call-template to pass the $result always as a number.

> 		</xsl:call-template>
> 	     </xsl:when>
> 		<xsl:otherwise><xsl:value-of 
> select="$result"/></xsl:otherwise>
>              </xsl:choose> 
> </xsl:template>

Quick test reveals that e.g. in Saxon 6.5.3 if you keep the $price bound to the same node-set and use a $cursor to point to the node being processed, with large documents the processing time goes down a third. Though you have to test if it helps your complete stylesheets and is faster in your choise of XSLT engine.

Cheers,

Jarno - this weeks Real Synthetic Audio <http://www.synthetic.org/play.html>

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