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Re: [xml-dev] %x;? - Opportunity for pedantry and exegesis
- From: Rob Lugt <firstname.lastname@example.org>
- To: Tim Bray <email@example.com>, firstname.lastname@example.org
- Date: Fri, 28 Sep 2001 10:24:59 +0100
Tim Bray wrote
> Consider the following content model fragment:
> as in <!ELEMENT a (%x;?, y)>
> It has been argued to me that this can't possibly
> ever be well-formed per a careful reading of the XML
> spec, and the arguments look correct to me.
> See production  and section 4.4.8.
> of course <!ELEMENT a ((%x;)?, y)> works.
> I've been told that the XHTML DTDs would suffer
> if this is true.
The OASIS/Nist conformance suite  contains many tests that check (a) PE
token expansion and (b) the grammar checking for content models (with
specific tests for misplaced multiplicity operators), so I think it unlikely
that any of the major XML processors would allow this through.
Our XML Validator  is used extensively for XHTML Validation and we have
not received any comments about the DTDs being invalid, so I presume they
are written to avoid this problem. FYI, here is the error message from
xmlvalid for your example:
--> test.dtd [1:16] : Fatal error: multiplicity specification '?' must
follow immediately after element name or ')'