Re: Extension/Extensibility examples in W3C Specifications:

Wonderful work Lynne,


Le 06 mai 2004, à 09:53, Lynne Rosenthal a écrit :
> Extension: characteristics that seem to always be true
>  - additional feature (@@functionality?) to the specification.

	yes an extension is something which broaden the possibility of the 
technology

	For example multiple output in XSLT engine with regard to XSLT 1.0 
(mainly used to produce more than one file on a drive, where it would 
not make sense at all in an user agent).

>  - does not break/negate the base specification
> @@Are the following always true?

	That's the difficult part. When someone create the tag "embed" which 
is not HTML 4.01.
	Does it negate negate the tag object?
	Can you implement "embed", if considered an extension, and not object, 
which is supposed to do the same?
	or an extension which will break or negate the base specification is 
an implementation of object with different semantics than the ones 
defined in the original specification.

>  - does not redefine existing technology (counterexample: CSS- By 
> providing alternatives to another technology (@@is this true?)

	What do you mean?
	Does not redefine: My previous example with embed/object.

> - non-standardized functionality or capability beyond the scope of the 
> specification. (counterexample: ??)

	infamous blink or marquee for HTML 4.01
	multi-ouput for xslt 1.0
	scrollbar colors for CSS

> Therefore, general definitions:
> a) Extension is the incorporation of additional features, beyond what 
> is defined in the specification.

	Good :)

> b) Extensibility is the ability of a specification to accept 
> extensions in a defined way.  A specification is extensible if it 
> provides a mechanism for any party to create extensions that do not 
> interfere with conformance to the specification.

	very good :)

I think the problem we have it's because the type of technologies 
inside W3C is broad.
	technologies to define Applications
		XML, RDF, XHTML Modularization
		HTTP, SOAP, Web Services
	technologies to create documents
		XHTML 1.0, XHTML 1.1, CSS, SVG, SMIL

It might be possible to define refinements. Class of Products ;)

> 4. What is being extended
> - the technology defined by the specification (example: XSLT, WSDL, 
> others?)
> - another technologies (RDF+OWL where OWL adds additional constraints, 
> others?)
> @@Where does XHTML Modularization fit? Where does CSS-3 fit?

See my other mail.
We can almost CSS-3 is now in the category of creating applications.
	An application of CSS 3 modules is CSS Mobile Profile.
	CSS Mobile Profile gives you the possible to create documents.

There is still no profile for Desktop User agents :((((


The more we dig into it... the more we identify difficulties :)