Here is a complete XSLT 1.0 transformation that solves exactly the problem.
This XSLT transformation:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:ext="http://exslt.org/common"
xmlns:f="http://fxsl.sf.net/"
xmlns:myAdd="f:myAdd"
xmlns:myParam="f:myParam"
exclude-result-prefixes="ext f myAdd myParam"
>
<xsl:import href="scanl.xsl"/>
<!-- -->
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:strip-space elements="*"/>
<!-- -->
<myAdd:myAdd/>
<myParam:myParam>0</myParam:myParam>
<!-- -->
<xsl:param name="pTruncateLength" select="772"/>
<!-- -->
<xsl:variable name="vFun" select="document('')/*/myAdd:*[1]"/>
<xsl:variable name="vZero" select="document('')/*/myParam:*[1]"/>
<!-- -->
<xsl:variable name="vrtfScanResults">
<xsl:call-template name="scanl">
<xsl:with-param name="pFun" select="$vFun"/>
<xsl:with-param name="pQ0" select="$vZero" />
<xsl:with-param name="pList" select="/*/*/body//text()"/>
</xsl:call-template>
</xsl:variable>
<!-- -->
<xsl:variable name="vScanResults"
select="ext:node-set($vrtfScanResults)"/>
<xsl:variable name="vindNode" select=
"count($vScanResults/*[. > $pTruncateLength][1]
/preceding-sibling::*)"/>
<!-- -->
<xsl:variable name="vrtfTruncInfo">
<xsl:for-each select="/*/*/body//text()">
<!-- -->
<xsl:variable name="vPos" select="position()"/>
<tNode id="{generate-id()}">
<xsl:attribute name="preserve">
<xsl:if test="$vPos < $vindNode">
<xsl:value-of select="string-length(.)"/>
</xsl:if>
<xsl:if test="$vPos > $vindNode">
<xsl:value-of select="0"/>
</xsl:if>
<xsl:if test="$vPos = $vindNode">
<xsl:value-of select=
"$vScanResults/*[$vindNode+1]
-
$pTruncateLength"/>
</xsl:if>
</xsl:attribute>
</tNode>
</xsl:for-each>
</xsl:variable>
<!-- -->
<xsl:variable name="vTruncInfo" select="ext:node-set($vrtfTruncInfo)"/>
<!-- -->
<xsl:template match="node()|@*">
<xsl:copy>
<xsl:apply-templates select="node()|@*"/>
</xsl:copy>
</xsl:template>
<!-- -->
<xsl:template match="text()[ancestor::body]">
<xsl:variable name="vAllowedLength"
select="$vTruncInfo/*[@id = generate-id(current())]/@preserve"
/>
<!-- -->
<xsl:value-of select="substring(.,1,$vAllowedLength)"/>
<xsl:if test="string-length(.) > $vAllowedLength
and
$vAllowedLength > 0
">
<strong> ...more</strong>
</xsl:if>
</xsl:template>
<!-- -->
<xsl:template match="myAdd:*" mode="f:FXSL">
<xsl:param name="pArg1"/>
<xsl:param name="pArg2"/>
<xsl:value-of select="$pArg1 + string-length($pArg2)"/>
</xsl:template>
</xsl:stylesheet>
when applied on the original source XML document:
<news>
<entry>
<title>Lorem Ipsum</title>
<body>
<p>
<strong>Lorem Ipsum</strong>
</p>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed malesuada auctor magna. Vivamus urna justo, pulvinar nec, sagittis malesuada, accumsan in, massa. Quisque mi purus, gravida eget, ultricies a, porta in, sem. Maecenas justo elit, elementum vel, feugiat vulputate, pulvinar nec, velit. Fusce vel ante et diam bibendum euismod. Nunc vel nulla non lorem dignissim placerat. Nulla magna massa, auctor et, tempor nec, auctor sit amet, turpis. Quisque odio lacus, auctor at, posuere id, suscipit eget, dui. Phasellus aliquam. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Proin varius. Phasellus cursus. Cras mattis adipiscing turpis. Sed.</p>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed malesuada auctor magna.</p>
<p>This text should not be displayed</p>
</body>
</entry>
</news>
produces the wanted result:
<news>
<entry>
<title>Lorem Ipsum</title>
<body>
<p>
<strong>Lorem Ipsum</strong>
</p>
<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed malesuada auctor magna. Vivamus urna justo, pulvinar nec, sagittis malesuada, accumsan in, massa. Quisque mi purus, gravida eget, ultricies a, porta in, sem. Maecenas justo elit, elementum vel, feugiat vulputate, pulvinar nec, velit. Fusce vel ante et diam bibendum euismod. Nunc vel nulla non lorem dignissim placerat. Nulla magna massa, auctor et, tempor nec, auctor sit amet, turpis. Quisque odio lacus, auctor at, posuere id, suscipit eget, dui. Phasellus aliquam. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Proin varius. Phasellus cursus. Cras mattis adipiscing turpis. Sed.</p>
<p>Lorem <strong> ...more</strong>
</p>
<p/>
</body>
</entry>
</news>
Do note the following:
The scanl stylesheet from the FXSL library is imported. This template is commonly used to accumulate data from processing a list of items. The function (the template matching myAdd:*) that does the actual processing is passed as a parameter to the scanl template. The other parameter that must be passed to it is the "initial" value from processing, which is to be returned if the passed list of items is empty.
The global parameter $pTruncateLength holds the maximum string length exceeding which the text must be truncated
