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Re: SD5 - Namespaces

From: Martin Bryan <mtbryan@sgml.u-net.com>
Date: Wed, 21 May 1997 09:09:06 +0100
Message-Id: <>
To: w3c-sgml-wg@w3.org
At 21:44 20/5/97 GMT, Peter Murray-Rust wrote:
> I had expected that experienced SGML'ers would have had a simple and
>elegant solution to this, but I haven't seen it.  
>It isn't essential to have the ':', but it's much less elegant without it.
The SGML way of saying that an element belongs to a different namespace than
that provided by the base DTD is to precede the element name by the name(s)
of the doctypes it does conform to in the form of a name group qualifier to
the element name, e.g. <(CML)MOL> and <(MathsML)EXPR>. If it is relevant in
more than one DTD you just say so, e.g. <(HTML|MYDTD)P>. I don't really see
much point in defining a new syntax for all this.

What is different is how you identify the alternate DTD in well formed
documents. Peter's solution of using the URL for the DTD in place of the DTD
name is one possibility, though I don't see what that gains you personally
unless for some reason the same DOCTYPE name is used by two DTDs (which will
really cause confusion). Another is to require that DTDs be identified as
entities within the internal subset, and then use the entity names as
qualifiers. I have already suggested a way of assigning unique names to the
namespaces associated with entities that form subsets of the main DTD. This
could also be used to assign DOCTYPE names to entities containing complete DTDs.

Martin Bryan, The SGML Centre, Churchdown, Glos. GL3 2PU, UK 
Phone/Fax: +44 1452 714029   WWW home page: http://www.sgml.u-net.com/
Received on Wednesday, 21 May 1997 04:13:28 UTC

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