W3C home > Mailing lists > Public > w3c-sgml-wg@w3.org > June 1997

Re: Parameter entities vs. GI name groups

From: Martin Bryan <mtbryan@sgml.u-net.com>
Date: Fri, 20 Jun 1997 19:03:07 +0100
Message-Id: <1.5.4.32.19970620180307.006a7c08@mail.u-net.com>
To: w3c-sgml-wg@w3.org
At 08:09 20/6/97 -0700, Tim Bray wrote:
>At 10:23 AM 20/06/97 -0500, David G. Durand wrote:
>>Let's relax compatibility with SGML and make PEs into straight text macros
>>rather than eliminating them. I think that this would be a win for users as
>>well, since the harders thing about learning PEs is that the string
>>substitution model is _not_ correct.
>
>Exact-a-mundo.  There is nothing wrong in principle with having
>a macro-processor facility in markup declarations, and I certainly
>agree 100% with the people who lament the loss of PEs on these
>grounds.  It's just that doing it in a way that's compatible with 
>8879's replacement rules is messy and complicated and hard to 
>understand.

>Having said that, I can't at this point support simply dropping 
>SGML compatibility on this issue (although it *would* solve the
>problem).

Come on - there are many areas of XML where you have placed semantic
constraints on the use of valid SGML features. Why should placing
constraints on the use of PEs be any different?

>WG8-folk on the list; are we the only ones who would like a
>radical simplification of the PE replacement rules, or is this
>another pending-for-the-subset item?  How about another SGML
>Declaration option that says PEs are just string-substituted
>without regard for where they may be? -Tim

We haven't got round to discussing this in committee, but the idea of adding
an option to restrict the use of PEs to:

a) just complete declarations
b) just complete model groups
AND
c) keywords for marked sections

would meet with my backing, and would seem to fit well with the rest of the
subsetting we are planning to do. (Changes to the SGML declaration are
'easy' and are expected. Changes elsewhere must be extensions.)
----
Martin Bryan, 29 Oldbury Orchard, Churchdown, Glos. GL3 2PU, UK 
Phone/Fax: +44 1452 714029  E-mail: mtbryan@sgml.u-net.com 
For details about The SGML Centre contact http://www.sgml.u-net.com/
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Received on Friday, 20 June 1997 14:04:36 EDT

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