> How to clarify the error message? What about (borrowing
> language from the above paragraph):
> "Invalid initial / or // in path step: Cannot select the root
> node of the tree that contains the context node, because the
> context item is not a node."

One of the difficulties in designing run-time error messages is that it's
dangerous to make assumptions about what constructs were used in the
original source code, since the same run-time code can be produced from many
different source code formulations.

 However, there are many cases where
Saxon saves information at compile time for use in the event of a run-time
error, so that better diagnostics can be produced, and it might be possible
to do the same here.

       <!-- gather all tokens into one sequence of strings, then group
by identical strings -->
       <xsl:for-each-group select="for $tags in //item/meta return
tokenize($tags, ',')" group-by=".">
           <xsl:sort select="." /> <!-- alphabetical order -->
           <h2><xsl:value-of select="."/>:</h2>
           <ul>
               <xsl:for-each select="//item[contains(meta, .)]">
                   <xsl:sort select="name"/>
                   <li>...

<xsl:for-each-group select="//item" group-by="tokenize(meta,',')">
  <xsl:sort select="current-grouping-key()"/>
  <h2><xsl:value-of select="current-grouping-key()"/>:</h2>
  <ul>
    <xsl:for-each select="current-group()">
      <xsl:sort select="name"/>
                   <li>...

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
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