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- To: firstname.lastname@example.org
- Subject: Re: [xml-dev] dynamically generated XML Schema?! R: [xml-dev] Number of active public XML schemas
- From: Chizzolini Stefano <email@example.com>
- Date: Wed, 3 Nov 2004 15:27:30 +0100
> -----Messaggio originale-----
> Da: Burak Emir [SMTP:Burak.Emir@epfl.ch]
> Inviato: mercoledý 3 novembre 2004 11.25
> A: Chizzolini Stefano
> Cc: firstname.lastname@example.org
> Oggetto: dynamically generated XML Schema?! Re: [xml-dev] R:
> [xml-dev] Number of active public XML schemas
> Chizzolini Stefano wrote:
> >>Which raises an interesting question: Should there be a non-XML syntax
> >>for XSDs like there is for RELAX NG? It's always been an article of
> >>faith for me that schemas should be written in XML, if for no other
> >>reason than not having to write another parser. But one does have to
>>I think there are some valid reasons for writing schemas in XML:
>>seamlessness, elegance and power. Adopting a "self-describing" language
>>syntax avoids the users from learning a new one and allows to leverage
>>existing applications derived from the original spec (in this case, XML
>>spec); I mean, for example, the chance to dynamically generate brand new
>>schemas through XSL transformations.
>One can of course endlessly discuss about syntax, but I have never
>understood the obsessiveness of marking up descriptions of XML data in XML.
>Who needs to dynamically generate schemas? The whole point of schemas is
>to be a widespread, well understood description of instances.
>If you generate a shining brandnew schema dynamically using X, you end
>up with a description that did not exist before. Ergo, the risk is that
>you do not have conforming documents.
You are reasoning on a static-scenario base! Instead, I imagine (for
example) the downstream work an agent could do depending on *that*
dynamically-generated schema: it could create dynamic database schemas or
even dynamically-conforming documents (but that's likely to be more suitable
for a semantically-rich scenario as the semantic web).
Anyway, I'm fascinated by the theoretical approach about language
generation: I wouldn't throw away *just* the mathematical possibility to
escalate an initial vocabulary through a pattern. Don't you care about it?
>Now one can dwell in discussion of hypothetical families of schemas, but
>for all my experience tells me about modelling, if you manage to
>understand what the common things are that make a bunch of schemas a
>family, then you can anticipate the extensibility you need, which
>removes completely the need for dynamic generation.
>What is a use case for dynamically generated schemas?
>Why does one need to use XSL for it ?
>Why couldn't one use non-XML syntax for it?
Simply because of its lack of transformability.