Re: [xsl] things about grouping

[David Carlisle <davidc@xxxxxxxxx>]

On 24/11/2012 05:54, Ihe Onwuka wrote:
> 1. <xsl:apply-templates select="current-group() except blah"/>
>
> still applies templates to blah


well current-group() except blah selects all nodes in the current group 
except blah nodes that are children of the current node. so it won't 
apply templates to "blah" if blah is interpreted as a relative xpath
from the current node. If you mean don't select elements in the current 
group that match blah then

current-group()[not(self::blah)]

is probably as clear as any of the alternatives.


> 2. If your group by patttern evaluates to  an empty element
> current-grouping-key() will yield nothing. However one may (as I did)
> want to get at the attributes of such an element but this is not
> possible.

group-by takes an expression rather than a pattern (starting-with and 
ending-with take patterns) the sorting key will be the  empty string in 
that case and should be usable just as any other string.

> 3. If you group-starting-with it's weird to then see things not
> encompassed by the starting-with expression appear as a group because
> they precede the first occurrence of the starting-with expression.
> While this works as specified  because for-each-group is a total
> function over the population it does result in a mismatch between the
> grammatical semantic and the exhibited behaviour, or to put it another
> way it does what it says in the spec but  doesn't do what it says on
> the tin.

If using starting-with you pretty much always end up testing if . 
matches the starting pattern and if so you are in the "bit before the 
first section"

David



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