W3C home > Mailing lists > Public > www-xml-schema-comments@w3.org > April to June 2000

Re: Entities

From: Priscilla Walmsley <priscilla.walmsley@xmls.com>
Date: Wed, 14 Jun 2000 10:02:48 -0400
To: <www-xml-schema-comments@w3.org>
Message-ID: <002901bfd609$3c700fd0$5ce70f3f@priscillaw01>

The Schema WG has asked me to respond to this question, which was logged in
our last call issues list as LC-64.

Neither general entities nor parameter entities have a direct representation
in XML Schema.

General entities can continue to be defined using DTD syntax in an internal
subset. There is nothing to prevent a document from having both a DTD and a
schema.  General entities were eliminated from XML Schema due to
well-formedness constraints of XML 1.0. If an XML 1.0 instance document were
to contain general entity references that could only be resolved by
referring to the schema, it would not be well-formed according to the XML
1.0 specification. Any of the existing parsers would  determine that the
document was not well-formed and would never even make it to validation.  An
additional motivation for eliminating general entities was very strong
support from the user community that there should be a clear separation
between composing documents (including resolving general entity references)
and validating them.

Parameter Entities were replaced by various XML Schema mechanisms that are
intended to cover many idiomatic uses of parameter entities for DTD
parameterization and reuse.  Specifically:

1. To include schemas from other locations (replacing external parameter
entities), use either include or import elements, as described in Section
6.2 of XML Schema Part 1: Structures.
2. To reuse content models (or pieces of content models), use named model
groups, as described in Section of XML Schema Part 1: Structures.
3. To reuse a list of attribute types, use attribute groups, as described in
Section of XML Schema Part 1: Structures.

Please feel free to respond with any further questions or concerns about
this topic; we certainly appreciate your feedback.  Otherwise, it is our
intention to close this issue without further action.

Thank you,
Priscilla Walmsley
VP, Research
XMLSolutions Corporation
7929 Westpark Drive Suite 100
McLean, VA 22102
(877) XML-XMLS

From: &References="dejudicibus@it.ibm.com
To: undisclosed-recipients:;
To: &References="www-xml-schema-comments@w3.org
cc: &References="ddj@mclink.it
Message-ID: <C12568CE.003AAA6C.00@d14mta01.it.ibm.com>
Date: Thu, 27 Apr 2000 12:41:19 +0200
Subject: Entities

Maybe this is trivial for those of you joined this group long time ago, but
I cannot find info about:

in one of the old draft of XML Schema, it was possible to define entities
too. For example

<textEntity name='rights'>All rights reserved.</textEntity>

Why that is no more possible? And what can I use to define entities, now?

Dr. Dario de Judicibus - IBM Global Services
EMEA Knowledge Management Consulting Group

[WORK] tel: +39.06.5966.2531, fax: +39.06.5966.5432, e-mail:
[HOME] fax: +39.06.2331.2293, e-mail: &References="dejudicibus@geocities.com
CE.003AAA6C.00@d14mta01.it.ibm.com>, icq:
[SITES] <http://www.geocities.com/~dejudicibus/>,
Received on Wednesday, 14 June 2000 10:08:28 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 23:08:47 UTC