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Re: SD2 - Structured Attributes

From: Martin Bryan <mtbryan@sgml.u-net.com>
Date: Fri, 16 May 1997 15:43:30 +0100
Message-Id: <1.5.4.32.19970516144330.0075fe68@mail.u-net.com>
To: w3c-sgml-wg@w3.org
At 12:32 16/5/97 +0700, James Clark wrote:
>I have difficulty in accepting structured attributes as a requirement. 

We already have many forms of "structured attributes". SGML Formal System
Identifiers are structured attributes, with the element structure embedded 
in the element content (e.g. file="<url FSIbase='abc.com'>file1.htm</url>".
Simarly XML pointers based on TEI external referencing are "structured
attributes".

The real question is whether, and where, such attributes can be formally
modelled.

HyTime lexical type definitions allow you to formally model any type of data, 
including attribute values. While they probably represent overkill as far as
XML is concerned the fact that they can be modelled externally from the
document using the application is important.

To be really general what you really need to do is to associated a notation
processor
with specific attribute values. How about the following extension to our use
of PI's

<element-x attribute-y="<?NOTATION-X?>Structured::Attribute::Value">

----
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 Friday, 16 May 1997 10:47:50 UTC

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