xml-dev - Re: SDD bogus

[Tim Bray <tbray@textuality.com>]

At 09:18 AM 5/8/98 -0400, Paul Prescod wrote:
>But that's not what I'm concerned about. I'm concerned because I believe
>this to be a valid XML document:
>
><?xml version="1.0" standalone="yes"?> 
><!DOCTYPE MEMO SYSTEM "http://www.sgmlsource.com/memo.dtd" [ 
><!ENTITY % mess-everything-up SYSTEM "mess.ent">
><!ATTLIST MEMO SECURITY CDATA "TOP-SECRET">
>]>
><MEMO></MEMO> 
>
>In my opinion, section 5.1 will require the non-validating parser to skip
>the attribute list declaration, even if memo.dtd is an empty file.

Welll, it can't be valid if memo.dtd is an empty file, because you
don't have <!ELEMENT memo .. > anywhere.  But yes, 5.1 suggests the
attribute default shouldn't be used.

>The receiver has no way of knowing that this case has occured if it uses a
>"standard parser"

If the sender is stupid enough to send something like this to a 
non-validating parser, he gets what he deserves.  If it's a validating
parser, then of course the emptiness of memo.dtd will be detected.

> (since XML's semantics are, for the moment at least,
>imprecisely specified, I only know what that means intuitively ... SAX,
>Lark, Expat, etc. would not give you enough information to detect this
>case).

Huh?

>This to me suggest that applications cannot trust the SDD and it must
>therefore be presumed to be meaningless.

You do raise a good question; it would seem that standalone='true'
*ought* to mean that the rule of 5.1 about the effect of 
external PE refs could be ignored.  Hmmmm -Tim


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