Re: [xsl] XML text search & replace

[Martin Honnen <Martin.Honnen@xxxxxx>]

a kusa wrote:
> Hello
>
> There is a requirement to search for a particular pattern in XML
> documents and replace them by reading another XML file and copying
> over the replacement text correcpinding to the original text.  I have
> been trying to use<xsl:analyze-string>  in xslt 2.0. but I am not sure
> how to read another XML file using this tag.
>
> As an example, if I have some text tagged within<para>  tags :
>
> <para>  this is a simple text</para>
>
> I have an external xml file of the form:
>
> <matchtext>simple</matchtext>
> <replacetext>hard</replacetext>
>
> In my<xsl:matching-substring>, can I use doc() to read the external
> XML file and replace the text?

Yes, simply build a regular expression and use that. Here is a sample:

<xsl:stylesheet
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
  xmlns:xsd="http://www.w3.org/2001/XMLSchema";
  exclude-result-prefixes="xsd"
  version="2.0">

  <xsl:param name="rep-file" as="xsd:string" 
select="'test2011032302.xml'"/>
  <xsl:variable name="rep-doc" as="document-node()" 
select="doc($rep-file)"/>
  <xsl:variable name="rep-pattern" as="xsd:string"
    select="string-join($rep-doc/replacements/replacement/matchtext, 
'|')"/>

  <xsl:key name="rep-key" match="replacement" use="matchtext"/>

  <xsl:template match="para">
    <xsl:copy>
      <xsl:apply-templates/>
    </xsl:copy>
  </xsl:template>

  <xsl:template match="para//text()">
    <xsl:analyze-string select="." regex="{$rep-pattern}">
      <xsl:matching-substring>
        <xsl:value-of select="key('rep-key', ., $rep-doc)/replacetext"/>
      </xsl:matching-substring>
      <xsl:non-matching-substring>
        <xsl:value-of select="."/>
      </xsl:non-matching-substring>
    </xsl:analyze-string>
  </xsl:template>

</xsl:stylesheet>

Assumes you have a file test2011032302.xml

<replacements>
  <replacement>
    <matchtext>simple</matchtext>
    <replacetext>hard</replacetext>
  </replacement>
</replacements>


There are some shortcomings, namely that word boundaries like \b are not 
supported by the XSLT/XPath regular expression language so it is 
difficult to prevent that e.g. "simple" in "simpleminds" is not 
replaced. If your XSLT 2.0 processor is AltovaXML Tools then I think it 
supports \b however.
Another problem occurs if the matchtext contains characters that are 
meta character in regular expressions like '?' or ')', you would first 
need to escape them with a function like 
http://www.xsltfunctions.com/xsl/functx_escape-for-regex.html.


--

	Martin Honnen
	http://msmvps.com/blogs/martin_honnen/