Re: Why Doesn't IE5 use the DTD to Validate?

[Chris Lilley <chris@xxxxxx>]

Paul Prescod wrote:
> 
> Jeff Greif wrote:
> >
> > I'm hesitant to enter this thread since I'm far from an expert, but...
> >
> > The problem is that the browser is really a processing application, for
> > example, using XSL to transform or render the document (at least in
> > principle).  If the document is supposed to conform to a DTD, the XSL code
> > will be a lot simpler if it can assume it will find what it wants where it
> > expects it.
> 
> I agree totally. But that's not what Chris said. He said that without the
> DTD there "is no parse tree." That isn't true on a technical level.

Correct, but actually that is not what I said. 

What I said was, if there is a parser which claims to be validating, and
it encounters an invalid document, and it silently fixes up the
invalidity, then the parse tree is not correct. And, if it is supposed
to be a validating parser, then it is supposed to signal an error and
halt when there is a validity error.

This is not to deny the existence or usefulness of well-formed documents
and non-validating parsers.

Just to point out the problems that result from misrepresentation - both
of invalid documents as valid, and of non-validating parsers as
validating.

> I did
> point out in my last message that a bug in the XML spec. makes the IE 5.0
> behavior fairly defensible. Just because a DTD is there does not mean that
> it is meant to be complete. 

You mean, it could just have entity declarations and no element or
attribute declarations? Or do you mean incomplete in that it may
reference some external parameter entities?

> If it is not meant to be complete then
> reporting that is not very useful to anyone.

Granted. But if it is complete, and the user believes that the instance
is valid because "it displays fine in IE" and "IE is a validating
parser" then that is a problem.

--
Chris


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