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Re: [SpecLite] Managing Normative References

From: Karl Dubost <karl@w3.org>
Date: Tue, 16 Nov 2004 11:17:46 -0500
Message-Id: <0D3B8B0D-37EB-11D9-9DFD-0003934BEBF0@w3.org>
Cc: www-qa@w3.org
To: Bjoern Hoehrmann <derhoermi@gmx.net>

Re-reading Bjoern's message in my exercise to write Good Practice and 
techniques for it.

Abstract of my comments in this mail.

===================
1. Think about the future versions of your normative references. If you 
think it might endanger your technology, don't make normative 
references to future versions, but to a specific date only.

2. Refer to the appropriate object, feature that you would like to use 
in your technology.

3. Refer to the appropriate part of the specification of the features 
you are using in your technology.

4. Don't make assumptions of the intents of other specifications.

5. Don't use contradictory concepts when you are defining things from 
other specifications. Indicate clear constraints on every features.

6. If you planned to update your specification with regards to a new 
version of a document in preparation, say it just as a warning. But be 
sure to not make it a requirement, a technology is a stable 
environment.

7. Do not refer to a generic name for a feature when you are giving a 
reference to another technology but to a precise designation of the 
technology.
==================

Le 13 juil. 2004, ā 02:55, Bjoern Hoehrmann a écrit :
> For example, a specification states
>
>   "The value of the attribute is a URI as in [RFC2396]".
>
> What does that mean for e.g. these examples:
>
>   * ...="http://www.example.org/#foo"
>   * ...="http://[3ffe:2a00:100:7031::1]/"
>   * ...="http://666.666.666.666/"
>   * ...="foo"
>   * ...="http://www.example.org/~björn"
>
> Are these currently legal?
> Will this change once RFC2396bis "obsoletes" RFC 2396?

1. Think about the future versions of your normative references. If you 
think it might endanger your technology, don't make normative 
references to future versions, but to a specific date only.


> I would say that the first example is illegal as the example uses a 
> URI Reference as opposed to only a URI, IMO, RFC 2396 clearly 
> distinguishes between those constructs.

2. Refer to the appropriate object, feature that you would like to use 
in your technology.

> Others sometimes disagree about that. Whoever would be right, it would 
> have been much better if the specification said
>
>   "The value of the attribute is a URI Reference
>    as defined in section 4 of [RFC2396]".
>
> as that would not allow any argument about it.

3. Refer to the appropriate part of the specification of the features 
you are using in your technology.

> The second example is a bit tricky, RFC 2396 does not include support 
> for IPv6 literals, the syntax has been introduced in RFC 2732 which 
> does *not* update RFC 2396, even though it is commonly referred to as 
> doing so, e.g. XML 1.0 Third Edition states
>
> [...]
>   Definition: The SystemLiteral is called the entity's system
>   identifier. It is meant to be converted to a URI reference (as 
> defined
>   in [IETF RFC 2396], updated by [IETF RFC 2732]), as part of the
>   process of dereferencing it to obtain input for the XML processor to
>   construct the entity's replacement text.
> [...]

4. Don't make assumptions of the intents of other specifications.


> This is also where things get even trickier than above. The definition
> clearly refers to URI References, so
>
>   <!DOCTYPE example PUBLIC "..." "http://www.example.org/#foo">
>   <example/>
>
> would be allowed as "http://www.example.org/#foo" is a legal URI
> Reference. But it is not, the specification points out,
>
> [...]
>   It is an error for a fragment identifier (beginning
>   with a # character) to be part of a system identifier.
> [...]
>
> Well, I complained about this misuse of terminology and the XML Core 
> WG told me [1] that using the term "URI Reference" is necessary here 
> as it allows absolute and relative references, which, I conclude, the 
> term "URI" does not. So it seems that according to their 
> interpretation the text proposed first would exclude the fourth 
> example as it uses a relative identifier.

I think this one is a bit harder. Basically it's

5. Don't use contradictory concepts when you are defining things from 
other specifications. Indicate clear constraints on every features.

It's a bit broader than the Normative references. It will be I guess 
covered in part on others Good Practices of the new spec gl

> And actually I was a bit too fast considering the DOCTYPE example 
> above as not allowed, it is allowed, the document is, if the processor 
> is able to locate the DTD either by using the public identifier or by 
> recovering from the erroneous system identifier, both well-formed and 
> valid. And yet it has errors. That's an "interesting" problem for 
> authors of conformance tools, they would have to write software that 
> says
>
>   The document is well-formed.
>   The document is valid.
>   Error: ...
> which would likely confuse users...

Yes :) bad design but not necessary about normative references problem.

> The third example is also tricky, the grammar of RFC 2396 allows it, 
> but I am not sure how it is supposed to be implemented; anyway, a 
> Validator would not probably consider the document valid regardless of 
> this issue.
> Until RFC2396bis joins these scene, which prohibes this syntax. What
> would that mean? Would my legal content become non-conforming? Would 
> my implementation that supports the syntax become non-confofming? Or 
> would it be neccessary that the specification gets updated to consider 
> RFC 2396bis?

See my point 1.

We could add a point 6.

6. If you planned to update your specification with regards to a new 
version of a document in preparation, say it just as a warning. But be 
sure to not make it a requirement, a technology is a stable 
environment.

> But let us not drift too much from the original issue. So far we have
> seen examples for unclear specification text and disagreement about 
> the interpretation of common terminology. Another problem that arises 
> is if the specification not only makes unclear references, but also 
> duplicates the content of other specifications.
>
> An example would again be the XML 1.0 Recommendation. The "Name"
> production that is used to define legal syntax for e.g. element names 
> is defined in terms of a concrete list of Unicode code points, Unicode 
> 2.0 at the time of publication of the Recommendation. The XML 1.1
> Recommendation states:
>
> [...]
>   Characters not present in Unicode 2.0 may already be used in XML 1.0
>   character data. However, they are not allowed in XML names such as
>   element type names, attribute names, enumerated attribute values,
>   processing instruction targets, and so on. In addition, some
>   characters that should have been permitted in XML names were not, due
>   to oversights and inconsistencies in Unicode 2.0.
>
>   The overall philosophy of names has changed since XML 1.0. Whereas 
> XML
>   1.0 provided a rigid definition of names, wherein everything that was
>   not permitted was forbidden, XML 1.1 names are designed so that
>   everything that is not forbidden (for a specific reason) is 
> permitted.
>   Since Unicode will continue to grow past version 4.0, further changes
>   to XML can be avoided by allowing almost any character, including
>   those not yet assigned, in names.
> [...]
>

This is a case of supersetting Unicode 2.0. Going further than the 
specification. I don't think it's exactly a problem of reference, but 
more a problem of Conformance Model or optional features.

That should be covered by something establishing strict requirements 
which are always testable, A kind of strict conformance, and a more 
loosy one if things which are predictable are included.


> Spite its name XML 1.0 has not been designed with extensibility in 
> mind; if it were, XML 1.1 would probably not exist as the benefit 
> would likelybe considered too small compared to the cost of having two 
> XML standards which is another problem.

Well as you said it's another story.

>   http://www.w3.org/mid/48457920-A9B9-11D8-9806-000A95BD86C0@bea.com
>
> lists some of the problems that emerged due to XML 1.1. Are simpler
> problem would be just whether
>
>   <?xml version="1.1" encoding="utf-8"?>
>   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
>       "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
>   <html xmlns="http://www.w3.org/1999/xhtml">
>   <head>
>   <title></title>
>   </head>
>   <body>
>   <p>...</p>
>   </body>
>   </html>
>
> is a strictly conforming document. The XHTML 1.0 Second Edition
> Recommendation refers to XML 1.0 many times, but section 3.1.1 only
> states
>
> [...]
>   A Strictly Conforming XHTML Document is an XML document that 
> requires only the facilities described as mandatory in this 
> specification. Such a document must meet all of the following 
> criteria:
> [...]
>
> Is an XML 1.1 document an "XML document"?

7. Do not refer to a generic name for a feature when you are giving a 
reference to another technology but to a precise designation of the 
technology.

"An XHTML document is an XML 1.0 document (version date)"


> And is the XML 1.0 Recommendation a normative reference of the XHTML 
> 1.0 Second Edition Recommendation? Appendix E of XHTML 1.0 SE is 
> "informative", so it seems that it is not. The HTML Working Group 
> however assured me that the lack of normative references is an error. 
> What the normative references are they still have to say...

Another issue. How to fix bogus specifications? :)))

> What a mess.

I guess we are not in a perfect world. What we are trying to do is to 
minimize the errors. but there will always be.

> For references to Unicode and ISO 10646 the I18N Core WG tries to 
> clean things up a little and provide
>
>   http://www.w3.org/TR/2004/WD-charmod-20040225/#sec-RefUnicode
>
> detailed information for editors on how to reference those documents,
> just like Unicode provides
>
>   http://www.unicode.org/unicode/standard/versions/#Citations
>
> similar material. That's good. I want more of that.

I'm taking that into considerations.

> Hmm, it seems that
> SpecLite only has
>
>   http://www.w3.org/TR/qaframe-spec/#reference
>
> [...]
>   B.3 Make a list of normative (and non-normative) references
>
>   Good Practice: Start now and keep adding to it as you go.
> [...]
>
> That's a bit insufficient... Say I am an editor, how to
>
>   * make a reference so that updates do affect my specification
>   * make a reference so that updates do not affect my specification

How to is very difficult but we will do a practice to make people aware 
of it. :)

> when should I choose which option, are there differences between the
> various specification production facilities, IETF, W3C, ISO, etc. that
> one should be aware of? I should be aware that normative references
> might always turn into a point of extensibility in my specification.
> I should also know what happens e.g. if my specification references
> spec X and spec Y replaces X but does not include all the features
> spec X included, what does that mean for my specification. And such.
>
> It also seems to be good practise to avoid duplication of normative
> content, if I state in my specification that feature X is defined in
> some other specification and works like $how_it_works, and the other
> specification is changed so that $how_it_works and that specification
> contradict, it is not clear how it works for my specification, so I
> should either state that the normative definition is in that reference
> and $how_it_works is informative, or the other way round.
>
> And going back to the original RFC 2396 example, it might be best to
> choose verbosity and state e.g.
>
>   "The value of the attribute is a relative or absolute URI
>    Reference with an optional fragment identifier as defined
>    in section 4 of [RFC2396] as updated by [RFC2732]."
>
> possibly stating something about updates like
>
>   "... or their successor(s)"
>
> or like
>
>   "Implementations also MAY conform to their successor(s)"
>
> and such. I would like "QA Specification Guidelines" to discuss such
> things to a reasonable extend, please make that happen :-)
>
> [1] http://lists.w3.org/Archives/Public/xml-editor/2001JulSep/0012.html
>
> regards.
>

-- 
Karl Dubost - http://www.w3.org/People/karl/
W3C Conformance Manager
*** Be Strict To Be Cool ***
Received on Tuesday, 16 November 2004 16:17:46 UTC

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