Subject: Re: [xsl] building a nodeset from selected nodes From: Wendell Piez <wapiez@xxxxxxxxxxxxxxxx> Date: Wed, 04 Jul 2001 19:00:33 +0100 |
<xsl:template match="table/query"> <xsl:for-each select="key('columns-by-name', column)"> ...do what you're going to do for each table/column 'called' by the query... </xsl:for-each> </xsl:template>
Hope that helps, Wendell
As is often the case, I found a solution while preparing this post to ask for help. I think there may be a simpler solution however (using XPATH/predicates?), plus I'd like to be able to encapsulate my solution in a call-template so I can reuse it. (As a newby I'd appreciate any other recommendations on usage, robustness, performance, etc.).
I'm trying to generate a node-set from my input where the selection is specified by a list of elements. Complicating matters somewhat is that the company I'm consulting for is using an older version of xalan that doesn't appear to support the nodeset() extension.
For example, given the input:
<table> <column> <name>A</name> <type>int</type> </column> <column> <name>B</name> <type>long</type> </column> <column> <name>C</name> <type>double</type> </column> <column> <name>D</name> <type>string</type> </column> ...
<query> <column>A</column> <column>C</column> </query> <query> <column>B</column> <column>C</column> <query> ... </table>
When I process the "query" elements, I'd like to construct a node-set which contains only nodes 'A' and 'C' (and their children), do something with those nodes, then process the next "query" which contains 'B' and 'C'. etc.
In psuedo-SQL, this would be like "SELECT * FROM nodes WHERE name IN ('A', 'C')".
Here's the xsl I've come up with so far:
... <xsl:for-each select="table/query"> <xsl:call-template name="get-column-nodes"> <xsl:with-param name="nodes" select="/.."/> <!-- create an empty node-set --> <xsl:with-param name="columns" select="column"/> </xsl:call-template> ... <!-- I'd like to have the node-set here --> </xsl:for-each> ...
<xsl:template name="get-column-nodes"> <xsl:param name="nodes"/> <xsl:param name="columns"/> <xsl:if test="$columns"> <xsl:variable name="col" select="$columns[1]"/> <xsl:variable name="new" select="//table/column[name=$col]"/> <xsl:variable name="newnodes" select="$nodes | $new"/> <xsl:variable name="rest" select="$columns[position()!=1]"/> <xsl:choose> <xsl:when test="not($rest)"> DO SOMETHING WITH THESE NODES... <xsl:for-each select="$newnodes"> <xsl:value-of select="."/> </xsl:for-each> DONE </xsl:when> <xsl:otherwise> <xsl:call-template name="get-column-nodes"> <xsl:with-param name="nodes" select="$newnodes"/> <xsl:with-param name="columns" select="$rest"/> </xsl:call-template> </xsl:otherwise> </xsl:choose> </xsl:if> </xsl:template>
====================================================================== Wendell Piez mailto:wapiez@xxxxxxxxxxxxxxxx Mulberry Technologies, Inc. http://www.mulberrytech.com 17 West Jefferson Street Direct Phone: 301/315-9635 Suite 207 Phone: 301/315-9631 Rockville, MD 20850 Fax: 301/315-8285 ---------------------------------------------------------------------- Mulberry Technologies: A Consultancy Specializing in SGML and XML ======================================================================
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