Hi Dimitre,

> > I imagine that a processor would be able to spot situations where
> > the position() or last() function had been called and only compose
> > the steps that were composable.
> 
>  It seems to me obviously not so -- I mean the general task of
>  spotting ***any*** function in the expression, that could reference
>  not only the specific item in the sequence. This includes any
>  user-defined functions.

Yes, you're right of course - the focus at the point at which the
user-defined function is called provides the focus for the body of the
function when it's defined by xsl:function, and that will propagate
through function (and named template) calls from those functions and
so on, making it impractical for the processor to spot.

I do think that the position of an item in a sequence is going to be
an important piece of information, particularly because items in
sequences can't be sequences themselves. Yet another
usability/optimisability trade-off I suppose.

Cheers,

Jeni

---
Jeni Tennison
http://www.jenitennison.com/


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