RE: [xsl] [answered] collecting multiple tokenize() results into one sequence

[Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>]

At 12:12 PM 7/24/2008, Mike wrote:
> > 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."

It's more general than that, since you'll also get the error for a 
path such as ".//node".

Maybe something like "Path expression invalid: 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.

Indeed. This is why saying less is often better. Hence, my suggestion 
says even less than the current "Cannot select a node here: the 
context item is an atomic value".

>  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.

Which could also be very helpful.

Hey Lars,

>        <!-- 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>...

How about:

<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>...

Grouping does not require that there be a single grouping key for 
each item grouped, and an item may appear in more than one group.

Cheers,
Wendell



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Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
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