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

Re: Entity and Element Addressing

From: David G. Durand <dgd@cs.bu.edu>
Date: Wed, 29 Jan 1997 17:35:43 -0500
Message-Id: <v02130503af156ca07f8b@[]>
To: w3c-sgml-wg@www10.w3.org
At 12:23 PM 1/28/97, Terry Allen wrote:
>I note from XML 1.0, s.v. 2.2, that in a well formed XML document,
>for each entity reference, the entity name must be declared in
>the doctype declaration (at that point, reference might be made
>to 2.9, in which the concept of internal and external subsets
>is introduced).  S.v. 4.2.2, the system identifier
>must be a URL (should the sentence following the Validity
>Check following production 71 start "The SystemLiteral"?).  It might
>be worth while pointing out that in xmllink, addressing by entity
>means addressing by URL using entities for indirection.  Is
>ENTITIES allowed?

It doesn't say so, so I assume not. Nor does ENTITIES seem that it would be
useful in this case.

>| If the reference type is ELEMENT,
>| then the HREF must be the value of a unique identifier attribute within
>"Unique identifier attribute" isn't language I can find in XML 1.0.
>Is "ID value" intended?  What of ELEMENTS, in the plural?  (In other
>words, is this really IDREF/IDREFS?)

I think so, but the language should be changed.

We have also considered allowing references based on any attribute value --
this would be nice, but would need to be defined first.

>What happens when the system identifier for the entity already
>contains a #?  What is the force of "leading" in "leading entity name"?

I don't think that this matters, actually. If the system identifier
identifies an XML document, then it presumably can't contain a '#', or it
contains a # with some fancy XML-linking query semantics, so that the IDREF
is applied relative to the result of following the pointer. Leading entity
name seems to mean that the entity name is first in a string like:


With the entity declaration
<!entity Foo SYSTEM "http://www.bar.com/bletch.xml">

Did I get the example right?

   -- David

I am not a number. I am an undefined character.
David Durand              dgd@cs.bu.edu  \  david@dynamicDiagrams.com
Boston University Computer Science        \  Sr. Analyst
http://www.cs.bu.edu/students/grads/dgd/   \  Dynamic Diagrams
--------------------------------------------\  http://dynamicDiagrams.com/
MAPA: mapping for the WWW                    \__________________________
Received on Wednesday, 29 January 1997 17:28:25 UTC

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