I am trying to isolate a regular expression group using the following XSLT:

<xsl:template name="extract_regex">
  <xsl:param name="regex">\Bulk Projects\Bulk ([\d]{3}) ([0-3][1-9](?i)(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|D ec)(?-i)(19|20)\d\d))</xsl:param>
  <xsl:param name="key_position">2</xsl:param>
  <xsl:param name="source_filename">\Project\Bulk 002 16Jan2006</xsl:param>
  <xsl:analyze-string select="$source_filename" regex="$regex">
    <xsl:matching-substring>
      <xsl:value-of select="regex-group($key_position)" />
    </xsl:matching-substring>
  </xsl:analyze-string>
</xsl:template>

I have explicitly defined the parameters to make my code snippet easier to follow. In this example, I am trying to extract the date (or the 2nd regex-group). Currently the code is not returning anything.

Any help is greatly appreciated.

First of all, you need regex="{$regex}".

But also, you need to fix your regular expression, it's using many constructs that are not allowed in the XPath regular expression language, for example \B, (?i), (?-i).

Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference

I have modified my template and am now using different sample data and regex:

<xsl:template name="extract_regex">
  <xsl:param name="match_value_object">\s*(.*)\s*,\s*([A-Z]{{2}})\s+(\d{{5}}(\-\d{{4}})?)\s*</xsl:param>
  <xsl:param name="key_position"/>
  <xsl:param name="input">New Haven, CT 06460</xsl:param>
  <xsl:analyze-string select="$input" regex="{$match_value_object}">
      <xsl:matching-substring>
          <xsl:value-of select="regex-group(2)" />
      </xsl:matching-substring>
  </xsl:analyze-string>
</xsl:template>

But I am receiving an error from Saxon:
com.sun.org.apache.xerces.internal.impl.io.Malform edByteSequenceException: Invalid byte 1
of 1-byte UTF-8 sequence

Please disregard the previous post. And thank you for your help.