Re: Extension/Extensibility examples in W3C Specifications

* Mark Skall wrote:
>> >I think the word *additional* is crucial - an extension which negates
>> >the base specification is not an extension but a change. Of course,
>> >quite what constitutes "negating" is domain dependent.
>>
>>I don't think so, changes make something ambiguous, you can infer
>>different things from the same thing prior and after the change,
>>even though the input remains the same. With an extension you have
>>different things where you naturally infer different things from.
>
>I agree with Jeremy.  When we write specs and include the concept of 
>extensions we say something like " the additional feature/function cannot 
>contradict or cause the non-conformance to other features/functions in the 
>spec."  Although extensions affect interoperability they are a fact of life 
>and we need to plan for them in  a way that would minimize conformance and 
>interoperability.  If we let extensions "break" the other parts of the 
>spec, we have chaos.

As I've said, it depends on the specification what is considered an
extension. However, must-understand extensions are more powerful than
others and it is sometimes desireable to have this additonal power.
Standardization takes care that such extensions are kept minimal by
standardizing the desired functionality.

Received on Wednesday, 5 May 2004 18:54:58 UTC