Since the FnL module doesn't yet support XSLT 2.0, we had to use this script. I'm posting this in the event there are others looking for similar solutions as I have noticed questions tend to repeat on this forum.

<xsl:template name="getFilename">
    <xsl:param name="input" />
    <xsl:choose>
      <xsl:when test="contains($input, '/')">
        <xsl:call-template name="getFilename">
          <xsl:with-param name="input" select="substring-after($input, '/')" />
        </xsl:call-template>
      </xsl:when>
      <xsl:otherwise>
        <xsl:value-of select="substring-before($input, '.')" />
      </xsl:otherwise>
    </xsl:choose>
  </xsl:template>

The call for that template is:

<td valign="top">
          <a href="{udt:FIELD}">
            <xsl:call-template name="getFilename">
              <xsl:with-param name="input" select="udt:FIELD" />
            </xsl:call-template>
          </a>
</td>

FIELD - is the column name in the table.