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RE: Vocabulary Combination

• To: xml-dev@l...
• Subject: RE: Vocabulary Combination
• From: "Hunsberger, Peter" <Peter.Hunsberger@s...>
• Date: Thu, 29 May 2003 12:51:19 -0500

Simon St.Laurent <simonstl@s...> wrote:

> At 12:02 AM 5/29/2003 -0700, Tim Bray wrote:
> >Don't be silly.  Why would you want names that are unique on a wide
> >scale
> >if you weren't going to be combining vocabularies?
> 
> That's not a silly question.
> 
> I use namespace identifiers in most of my processing, even
> when I don't 
> plan to be combining vocabularies in single documents.  It 
> means I can 
> create pipelines which handle multiple vocabularies correctly, for 
> instance, even when using tools that have long since 
> forgotten that DOCTYPE 
> exists.

The other way to look at is that name spaces are a bit like "safe $ex" for
data: you never know where it's going to go.  Wrap it up a little to give it
some extra protection...

> The vocabulary-combination issue seems to have driven the
> scoping issues 
> and made for a lot of never-ending conversations.  While I've 
> written code 
> that now deals with the scoping, it's still vastly 
> complicating, and only 
> rarely useful - I have a hard time seeing that as having hit an 80/20.
 
We've got code where we combine presentation semantics with other data (as
in the early examples of this thread) coming out of the back end.  Even
though the vocabularies are distinct we still namespace them.  Once we're
moving the data towards the front end the first thing we do is strip out the
name spaces, but at that point we're in well defined transforms that
understand the combined contexts. The data combination transforms
essentially encapsulate business logic and leverage the name spaces to do
so.  The subsequent transforms are purely presentation and as such need to
know the context precisely at which point name spaces are _almost_
irrelevant ("almost" since I'm sure one can generate examples where name
spaces continue to be of use).

All of which is a long winded way of arriving at the conclusion that: you
don't need namespaces if you precisely understand the context of the
combined vocabularies, but until you combine the vocabularies you probably
want the name spaces if only to help in combining the vocabularies.

• Follow-Ups:
  • Choosing when to namespace (was Re: Vocabulary Combination)
    • From: "Seairth Jacobs" <seairth@s...>

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