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Re: Update on namespaces

From: len bullard <cbullard@hiwaay.net>
Date: Tue, 10 Jun 1997 22:32:23 -0500
Message-ID: <339E1C47.2C83@hiwaay.net>
To: w3c-sgml-wg@w3.org
Andrew Layman wrote:
> 
> I indeed think of types as equivalent to notations, as your mail points
> out. Looking at notations, we see that they identify the format of an
> external binary entity, and associate that format with a public
> identifier.  That is, notations do specify data types, and within the
> limits of XML public identifiers, notations are universally unique.

Not formally, but my sense of notations is that they declare handlers
for 
types of information.  The sticking point has been that is a role
reserved 
for MIME.  Several times Eliot has given examples of how this can be
mapped.
 
> Notations suffer from a few problems from our point of view, and that is
> that they apply only to external entities, and types useful for routine
> data processing as types such as INTEGER or DATE are not standardized.

Can a notation declare these types externally for routine use
internally?

> The concepts are very similar, and maybe we can extend the idea of
> notation to cover element contents.

Is it possible to use a notation to declare a DTD formally?  IOW, can 
or should a notation declare an SGML/XML DTD within the DTD of another 
application?
 
> However, notations are not the same as namespaces. Namespaces are not
> data types. Namespaces are a general mechanism that allows any element
> name (or by extension, any name) to be associated with a particular kind
> of system literal, a URI, and thereby namespaces allow any name to be
> made universally unique. 

I have to read up on URIs to be sensible here.

> Notations contain a mechanism by which
> notations can be universally disambiguated; but it only works for
> notations, it isn't general. Namespaces is a general mechanism that
> universally disambiguates any name.

Ok.  Does a namespace have to be universal? Does the DTD declare a 
namespace that is local?  

Provocative and maybe dumb:  Is it better to handle the issues of
namespaces 
in the DOM?  If so, does the DOM handle namespaces for VRML or only 
for W3C markup applications? 

len
Received on Tuesday, 10 June 1997 23:32:45 EDT

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