Re: "sorted" axis (was: Remove duplicates from a node-set according to content)

[James Clark <jjc@xxxxxxxxxx>]

Kay Michael wrote:
> 
> > From: James Clark [mailto:jjc@xxxxxxxxxx]
> >
> > The saxon:group element is a pretty interesting extension.  My initial
> > thought is why not make it an empty element that applies to its parent
> > xsl:for-each or xsl:apply-templates element, like xsl:sort?  That way
> > you can have multiple grouping levels: there would be one level of
> > xsl:item nesting per xsl:group element.
> >
> It started life as a group-by attribute on xsl:for-each when sorting was
> controlled by a similar order-by attribute. I've always been able to get by
> with one level of grouping but general nesting would be far better.
> 
> I'm not sure an empty element feels right: there's a need to delineate the
> processing that happens at each level of grouping,

Isn't that what the saxon:item does?

> something like:
> 
> process node set X sorted by Y then Z
> -- for each group with common Y do
> -- <h2>Y</h2>
> ---- for each group with common Z do
> ---- <h3>Z</h3><ul>
> ------- for each item do
> ------- <li>stuff</li>
> ------- end for
> ---- </ul>
> ---- end for
> ---<hr/>
> -- end for
> end process

Couldn't you think of it as?

for each member of (node set X sorted by Y then Z, grouped by Y then by
Z)
-- <h2>Y</h2>
---- for each member of the current group do
---- <h3>Z</h3><ul>
------- for each member of the current group do
------- <li>stuff</li>
------- end for
---- </ul>
---- end for
---<hr/>
-- end for
end for

James



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