XSLT Cookbook

Creating Generic Bounded Aggregation Functions

Problem

You want to create reusable templates for performing a wide variety of bounded aggregation operations.

Solution

 <xsl:template name="generic:bounded-aggregation"> <xsl:param name="x" select="0"/> <xsl:param name="func" select=" 'identity' "/> <xsl:param name="func-param1"/> <xsl:param name="test-func" select=" 'less-than' "/> <xsl:param name="test-param1" select="$x + 1"/> <xsl:param name="incr-func" select=" 'incr' "/> <xsl:param name="incr-param1" select="1"/> <xsl:param name="i" select="1"/> <xsl:param name="aggr-func" select=" 'sum' "/> <xsl:param name="aggr-param1"/> <xsl:param name="accum" select="$generic:generics[self::generic:aggr-func and @name = $aggr-func]/@identity"/> <!-- Check if aggregation should continue --> <xsl:variable name="continue"> <xsl:apply-templates select="$generic:generics[self::generic:func and @name = $test-func]"> <xsl:with-param name="x" select="$x"/> <xsl:with-param name="param1" select="$test-param1"/> </xsl:apply-templates> </xsl:variable> <xsl:choose> <xsl:when test="string($continue)"> <!--Compute func($x) --> <xsl:variable name="f-of-x"> <xsl:apply-templates select="$generic:generics[self::generic:func and @name = $func]"> <xsl:with-param name="x" select="$x"/> <xsl:with-param name="i" select="$i"/> <xsl:with-param name="param1" select="$func-param1"/> </xsl:apply-templates> </xsl:variable> <!-- Aggregate current $f-of-x with $accum --> <xsl:variable name="temp"> <xsl:apply-templates ...