RE: [xsl] Truncating output of a node

Subject: RE: [xsl] Truncating output of a node
From: Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>
Date: Thu, 19 Apr 2001 16:35:43 +0100
At 08:20 PM 4/19/01, you wrote:
I guess another possibility it to output n characters and add '...' at the
end to create the summary. Is that any easier?

Considerably easier, although what you stipulate about how the "." may be good enough , makes the harder problem easier too.

It would be really easy if you didn't care about those embedded <span> elements. Then you could just do:

<xsl:variable name="allowable-length" select="100"/>
<!-- let's say 100 characters is a good number -->

<xsl:template match="summary">
  <xsl:value-of select="substring(., 1, $allowable-length)"/>
  <xsl:if test="string-length(.) &gt; $allowable-length">

But with those embedded <span> elements, things are harder. I'm not going to tackle the "break on sentences" problem; we'll go with testing on string length.

Maybe something like:

<xsl:variable name="allowable-length" select="100"/>

<xsl:template match="summary">

<xsl:template name="string-segment">
<!-- outputs as much of the string as will fit -->
<xsl:variable name="string-before">
<xsl:for-each select="$preceding-sibling::*|preceding-sibling::text()">
<!-- counting only elements and text nodes, not comments or
processing-instructions -->
<xsl:value-of select="."/>
<xsl:variable name="length-before" select="string-length($string-before)"/>
<xsl:if test="$length-before &lt; $allowable-length">
<!-- part of this string will fit! we're in business -->
<xsl:variable name="length-left" select="$allowable-length - $length-before"/>
<xsl:value-of select="substring(., 1, $length-left)"/>
<xsl:if test="string-length(.) &gt; $length-left">

<xsl:template match="summary/text()">
  <xsl:call-template name="string-segment"/>

<xsl:template match="summary/span">
  <b> <!-- I'm just making all spans <b>; do what you like -->
    <xsl:call-template name="string-segment"/>

If I'm thinking about this the right way, it'll work as long as you only have text nodes and span elements in your summary, and you don't have any elements you need to process *inside* the spans, just text nodes.

Note -- untested: sure to be typos and maybe worse. Also -- expect performance to be pretty lame....

Hope this helps!

Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
Mulberry Technologies, Inc.      
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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