adding
<xsl:if test="*[2] or not(definition)">
<xsl:message>.....

in lots of places makes the transformation resemble a schematron schema
more than a transformation at times (and probably the xslt engine spends
as long doing those checks as anything else), but having the messaging
inserted at the point that the transformation fails (often an
xsl:otherwise or match="*" default case) rather than have a separate
schematron try to second-guess what input the transformation can validly
handle means that the error reporting is more accurate, and (perhaps)
more likely to get run every time.

<xsl:variable name="unexpected" select="not(count(definition) eq 1)"/>
<xsl:apply-templates mode="erroneous" select=".[$unexpected]"/>

Cheers,
Wendell

--
======================================================================
Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
Mulberry Technologies, Inc.                http://www.mulberrytech.com
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
======================================================================