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

Re: HTML WG last call remark (no way to declare entities?)

From: Dan Connolly <connolly@w3.org>
Date: Fri, 05 May 2000 08:44:04 -0500
Message-ID: <3912D024.BBEA1401@w3.org>
To: www-xml-schema-comments@w3.org, Steven Pemberton <steven.pemberton@cwi.nl>
Steven Pemberton wrote:
> 
> The HTML WG has requested me to relay to you a request that XML Schemas
> include a facility to define at least character entities (such as &eacute;).

We tried that before, but it didn't work out well; we weren't
sure we liked it, but we put the idea out for review, and
the feedback was overwhelmingly negative:

"The provision within XML Schema: Structures of a mechanism for defining
         parsed entities presents problems for the relationship between
         schema-validity and XML 1.0 well-formedness, since references
to entities
         defined only in a schema are undefined from the XML 1.0
perspective. Strictly
         speaking, a well-formed XML document may contain references to
undefined
         entities only if it is declared as standalone='no' and contains
either an external
         subset or one or more references to external parameter entities
in their
         internal subset. We get around this by [Definition: ] defining
a nearly
         well-formed XML document to be one which either is well-formed
per XML
         1.0, or which fails to be well-formed only because of undefined
general entity
         references, but which would be well-formed if it were
standalone='no' and
         identified an external subset. We consider this justified on
the grounds that the
         use of a namespace declaration which refers to a schema
functions rather as
         an external subset, and from the XML 1.0 perspective such a
reference
         almost of necessity renders the document non-standalone when
         schema-validation is applied."

-- http://www.w3.org/1999/05/06-xmlschema-1/#conformance-schemaValidity

If you can think of a less awkward way to do it, let us know.

Otherwise, I think it's most likely that the WG will decline your
request.

If you find this explanation to be satisfactory justification for
us to decline your request, please let us know by withdrawing
your request.

> While we recognise that the full entity mechanism might be a burden, HTML
> markup typically contains a lot of character entities, and we would like to
> be able to define them when using schemas without having to fall back to a
> DTD subset.

I'm afraid that's about the only way I can see to make it work.

Another option is to use <eacute/> in stead of &eacute, but
that requires application-level support rather than
being handled by the XML processor, and it
won't work in attribute value literals.

-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Friday, 5 May 2000 10:05:12 UTC

This archive was generated by hypermail 2.3.1 : Wednesday, 7 January 2015 14:49:52 UTC