Re: $p:position available everywhere

On 5/1/07, Norman Walsh <ndw@nwalsh.com> wrote:
>
> / Innovimax SARL <innovimax@gmail.com> was heard to say:
> | I submit a proposal to make $p:position available everywhere
> | It would be 0 for an empty sequence
> | and 1 for a single document
> | or the position of the current document in the sequence
>
> I'm not sure how "everywhere" applies. Can you give an example of
> somewhere else you might want it? I suppose in p:for-each, but I
> can't think of anywhere else where it makes sense.



Clearly, p:for-each

If we say that

Axiom A:
"evaluating an XPath over a sequence of document is equivalent to the
sequential evaluation of that XPath over each document of the sequence"

Then it could be done everywhere we have an XPath evaluated over a sequence
or not

More generally, we could say that all $p:* variable are stable on each
document evaluation, but can vary trough the sequence evaluation, and we
should reserve $p:* variables for useful information ($p:base-uri,
$p:is-last-in-sequence, etc.)

If we don't say Axiom A, then we could be able to evaluate something like
"count(/)" ?




| PS : in a case of empty sequence what would be the evaluation of an
> | XPath expression ?
>
> That probably needs to be considered on a case-by-case basis.
>
>
>
let's start with :
* "/" on an empty sequence ?


-- 
Innovimax SARL
Consulting, Training & XML Development
9, impasse des Orteaux
75020 Paris
Tel : +33 8 72 475787
Fax : +33 1 4356 1746
http://www.innovimax.fr
RCS Paris 488.018.631
SARL au capital de 10.000 €