[whatwg] Re: Doctype FPI

Terje Bless link at pobox.com
Wed Jul 14 02:43:04 PDT 2004

Hash: SHA1

Ian Hickson <ian at hixie.ch> wrote:

>On Tue, 13 Jul 2004, Terje Bless wrote:
>>Could you explain how you intend to formally define -- in a
>>machine-processable manner -- the syntax? Without the notion of
>>Validity, how do you intend to machine-check conformance?
>The question assumes that _with_ the notion of validity, you have a way
>to machine-check conformance.

No, it does not. But let me rephrase for your benefit.

Do you forsee specifying the deliverables of the WHAT WG in a way that
supports machine verification of basic syntactic conformance, analogous to
Validation in SGML applications (including XML)?

If so, in what way and using what tools?

I take it that the answer is no, based on your following statements, but...

>The question assumes that _with_ the notion of validity, you have a way
>to machine-check conformance. This is a myth. See:
>http://ln.hixie.ch/?start=1029524973&count=1 and the answers:

I dispute the relevance of these claims to the point you are attempting to
make. There is no doubt Validation — and even Schema verification — is limited
in scope. This does not mean the facility and process are without value.

In fact, in my opinion, your examples serve better to illustrate that it would
be better to provide for _more_ Validation rather than less, since anything
that can be flagged by an automated process is something you don't have to
spend time on puzzling out manually.

Without an objective check like Validation, the final arbiter (in practice) of
what is "correct" is how a page looks in a browser. None of your four examples
from the "Quiz" would be possible to identify that way, with the possible
exception of the poorly chosen alternate text (and even that is dubious in the
established confusion with @title/tooltips).

>>Since this corresponds to neither SGML nor XML, how do you envision
>>bringing the toolset into being?
>Since nobody has done it so far (RelaxNG is getting closer, but even
>that is still a long way from conformance checking), why would I
>suddenly have the responsibility for doing it?

There is a quite large body of software tools, standards work, literature, and
community built up around SGML (and XML). By abandoning both you are also to a
large degree abandoning these. I am trying to understand whether you have
considered this and its implications.

I did not claim you had any responsibility either way; I asked how you
envisioned handling this problem. A valid response to this question is of
course "I don't".

>>Since you seem to envision not actually having any DTD to speak of,
>>where do you see named entity references fitting into the picture?
>If the author wants entities, then the (otherwise mostly empty) DTD
>would be the right place for them.

So authors are expected to edit the DTD? Do you intend for this to happen in
either of the internal or the external subset, or just one? Does this imply
that the prose of the specification will define a set of known entities (such
as, e.g. °)?

>>What SGML Declaration do you intend be in effect?
>I do not intend to pretend that current UAs even have the concept of an
>SGML Declaration. (The only UA that I know of that supports the concept,
>in fact, is the validator.)

I am not familiar with the inner workings of the UAs you probably have in
mind, but I would be very much surprised if they do not have a facility that
is at least analogous to the function of the SGML Declaration.

But since _this_ question presupposes a desire for machine-verification it
becomes irrelevant so long as you do not intend to provide such a facility, or
one based on a different system which does not make use of SGML Declarations.

>>>Then, assuming we don't ever introduce elements with optional tags
>>>(which I highly doubt we will), we never need to update the DTD again.
>>But assuming you don't -- Will the SGML Declaration reflect this (by
>>e.g. removing the corresponding SHORTTAG features)?
>Uh. If we introduced an element with optional end tags, it would be
>pretty stupid of us to then disallow optional end tags, no? Or am I
>missing something.

You've misread the question. Iff you intend to never introduce elements with
optional tags, will you alter the SGML Declaration to reflect this intent (by
disallowing certain markup minimization features)?

Note that this again presupposes that you intend to make use of SGML
Validation as a machine verification facility. Without it the question becomes

>>Will the conformance requirements require document instances be
>>fully-tagged? Amply-tagged?
>Not sure what you mean by "tagged".

Are you familiar with SGML? WebSGML (Annex K)?

  K.2.2 Definitions related to validity assertions
  K.2.2.1 fully-tagged document instance:

  A document instance in which a start-tag with a generic identifier,
  and an end-tag, are present for every element, and the attribute name
  is present in every attribute specification in the start-tag.

  Note 1: An SGML declaration requires document instances to be
  fully-tagged if it specifies OMITTAG NO and SHORTTAG STARTTAG EMPTY NO
  and ATTRIB OMITNAME NO. A system should offer means, such as a
  parameter to the invocation of processing, to request validation of
  whether an instance is fully-tagged even when the SGML declaration
  does not require it to be.
]]] - http://www.sgmlsource.com/8879/n0029.htm

K.2.2.4 defines amply-tagged document instances, as «A document instance whose
use of markup minimization does not require access to a document type
declaration.» (see above URL for the rest)

>Yes. People rely on DTDs in a way which has led to millions of authors
>to have a false sense of having done the right thing, when in fact their
>documents are sometimes worse than documents that are syntactically
>slightly broken but semantically fine.

Please try to examine that paragraph in an objective fashion. Your language
appears to be designed to evoke an emotional response ("millions of authors",
"false sense", "the right thing", etc.). If you would like to make this point,
I would appreciate it if you could recast it in more neutral language so I can
better understand it.

[ reordered and snipped quote ]
>>So because the facility is not perfect you propose to do away with it
>Yes. […]

Thank you. This adequately answers my question.

>Schemas aren't much better.

In what sense? Your arguments above partly focus on DTDs inability to specify
datatypes and provide attribute syntax verfification, something which Schema
facilities seem to offer. Is your claim based on their inability to provide
semantic and stylistic verification?

- -- 
"I don't want to learn to manage my anger;
 I want to FRANCHISE it!" -- Kevin Martin

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