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RE: IDs - make them case sensitive

From: W. Eliot Kimber <eliot@isogen.com>
Date: Mon, 30 Jun 1997 22:07:21 -0900
Message-Id: <>
To: w3c-sgml-wg@w3.org
At 07:45 PM 6/27/97 -0700, Murray Altheim wrote:
>Andrew Layman <andrewl@microsoft.com> writes:
>> Lauren and Tim have some good points regarding IDs.  It is a benefit if
>> an id can easily map between an element and either a real world entity
>> or an object in another database system.  Unless there is some bad
>> consequence to permitting a freer use of characters, relaxing the
>> restrictions just seems to simplify document construction and
>> processing.
>Well, the first thing that comes to mind would be that XML documents using
>IDs not beginning with a name start character would not work in existing
>SGML systems, and my understanding of the RCS is that it's not possible to
>modify what constitutes a valid name start character to allow digits. This
>would simply make XML documents and systems that create them incompatible
>with SGML. I certainly stand to be corrected, but it seems pretty explicit
>in 8879.

Not true, if I understand your point.  The reference concrete syntax does
not specify the digits as name start characters, but XML is not using the
reference concrete syntax and few useful SGML tools do not allow variant
syntaxes (and therefore will allow you to redefine the name start
characters) [The only one I can think of off hand in Panorama, which
doesn't read SGML declarations at all and simply provides a longer name
length automatically.].

Thus, adding digits (or anything else within reason) would not make XML
documents incompatible with SGML systems in general, although it might with
particular tools (for example, adding "_" to name start could thoroughly
confuse ADEPT*Editor, which uses "_" as a "reserved tag prefix"--not a good
implementation choice in retrospect). 


<Address HyTime=bibloc>
W. Eliot Kimber, Senior Consulting SGML Engineer
Highland Consulting, a division of ISOGEN International Corp.
2200 N. Lamar St., Suite 230, Dallas, TX 95202.  214.953.0004
Received on Tuesday, 1 July 1997 00:11:24 UTC

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