Re: Problem with xhtml-basic

Hello,

"Don Griffiths" <GriffithsD@cbs.curtin.edu.au> wrote:

> I am tying to use the xhtml-basic DTD in XMLSpy, but validation fails
> when "http://www.w3.org/TR/xhtml-modulatization/DTD/xhtml-framework-1.mod" is parsed.  The error reads "entity xhtml-xlink.mod may not be used in this location"  The error occurs two lines below the 
> comment  <!-- placeholder for XLink support module -->

I think this is a problem of XML Spy.  I just tried XML Spy 3.5, and
I observed the same problem, but I don't think XML 1.0 has such
limitation, and I have tested the DTD with various validating XML
processors including the latest version of Xerces-J, Xerces-C,
XML4J, XML4C, Crimson and nsgmls, and none of them reported this
as an error.

Interestingly, if I change

  <!-- placeholder for XLink support module -->
  <!ENTITY % xhtml-xlink.mod "" >
  %xhtml-xlink.mod;

to

  <!-- placeholder for XLink support module -->
  <!ENTITY % xhtml-xlink.mod " " >
  %xhtml-xlink.mod;

then XML Spy doesn't complain about it anymore.  So I think it should
have been a warning for DTD designers rather than a validation error.
In general, an empty ENTITY declaration is not a good thing, but since
XHTML Basic DTD is designed to be modular, there's a bunch of
"placeholder" ENTITY declarations that are initially declared as empty.

Hope this helps.

Regards,
-- 
Masayasu Ishikawa / mimasa@w3.org
W3C - World Wide Web Consortium