Re: Schemas and entities (was "And the DTD says, "I'm NOT dead yet!!")

[David Carlisle <davidc@nag.co.uk>]

> You're making things _much_ too complicated.

agreed, but a small comment on:

>    a) create an instance per XML 1.0 plus Namespaces, with entity
>       definitions in the internal or external subset, but nothing else
>       (i.e. no ELEMENT or ATTRIBUTE declarations);
>    b) process with any conformant XML processor (if entities are all
>       defined in internal subset) or with any validating XML processor (if
>       any entities are defined in external subset);
>    c) process with a schema-aware processor.

If in a) if you only make the entity declarations, and they are in an
external subset, then in b) don't you need a non-validating XML
processor that reads external subsets.

You suggest using a validating processor but that would generate errors
as the document would be invalid, wouldn't it?

Non validating parsers aren't obliged to read external subsets but most
seem to, or can at least be configured to. So in practice this doesn't
seem to cause any real problems. (Similar issues relate to XSL use
of ID declartions.)

Alternatively of course one can use a full DTD in stage (a) that does
declare all elements and attributes, although then if you use a
validating XML parser, depending on the document type, there may or may
not be much more for the schema validation to check.



David

_____________________________________________________________________
This message has been checked for all known viruses by Star Internet delivered
through the MessageLabs Virus Control Centre. For further information visit
http://www.star.net.uk/stats.asp