- From: Henry S. Thompson <ht@cogsci.ed.ac.uk>
- Date: 20 Nov 2002 14:27:23 +0000
- To: Stefan Wachter <Stefan.Wachter@gmx.de>
- Cc: xmlschema-dev@w3.org
Stefan Wachter <Stefan.Wachter@gmx.de> writes:
> 1.
>
> The spec. defines BNFs for the valid XPaths. However, it also states
> (at 2.2) that XPaths whose abbreviated forms correspond to the BNFs
> are also valid with the restriction that only the 'child' (and
> 'attribute' axes in case of fields) are used.
>
> Yet, the BNFs also use the 'self' and the 'descendant-or-self' axes.
> Therefore I think that these axes should also be allowed for the
> XPaths covered by (2.2).
'self' is '.', which is allowed by the BNF, as is '//', which is
descendant-or-self.
> 2.
>
> The BNFs allow the '//', i.e. a 'descendant-or-self' step only at the
> beginning. I think this restriction is not necessary because it does not ease
> implementations and is conceptually not justified.
The restriction to one, initial, use of //, is intended to reduce
implementation complexity for streaming implementations.
> 3. The 'descendant' axis should also be allowed.
What use case do you have in mind?
ht
--
Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
W3C Fellow 1999--2002, part-time member of W3C Team
2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 131 650-4440
Fax: (44) 131 650-4587, e-mail: ht@cogsci.ed.ac.uk
URL: http://www.ltg.ed.ac.uk/~ht/
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Received on Wednesday, 20 November 2002 09:27:26 UTC