W3C home > Mailing lists > Public > public-cdf@w3.org > March 2006

Re: CDR: Appendix B lacks testable conformance criteria for user agents

From: Maciej Stachowiak <mjs@apple.com>
Date: Sun, 19 Mar 2006 22:17:32 -0800
Message-Id: <1ADB69EE-3649-4F84-A1D3-A9968AA14740@apple.com>
Cc: public-cdf@w3.org
To: Steve K Speicher <sspeiche@us.ibm.com>


On Mar 13, 2006, at 6:55 AM, Steve K Speicher wrote:

> Maciej Stachowiak <mjs@apple.com> wrote on 03/08/2006 05:51:51 PM:
>> I think it would have to define what counts as a profiled subset. May
>> anyone define the profile?
> Sure
>> Does it have to be defined by a W3C spec?
> No doesn't have to be, as you see we reference ECMA standards from our
> WICD profiles.
>> Does DOM Level 2 Core count as a profiled subset of DOM Level 3 Core?
> Can DOM Level 2 Core applications run in a DOM Level 3 Core UA,  
> then yes.
>> Does SVG uDOM (the core-related part) count?
> If criteria above applies, then yes.
>> I think this criterion  is still not testable as written.
>
> A profiled subset, is a reduced set of capabilities from the original
> specification.  Meaning, that the subset doesn't add any new features,
> only strips them out.  Content that conforms to the profiled subset  
> must
> successfully be processed/rendered by a compliant UA of the full/ 
> superset
> specification, in other words the full UA doesn't need to know its  
> subset
> content.
>
> So conformance statements, in addition to the above, could be:
>
> UA Conformance:
>   "A conformant user agent of a superset profile specification must
> process subset profile content as if it is the superset profile  
> content."
> Profile Conformance:
>   "A conformant subset profile must not add new features from their
> corresponding superset specification."
>   "A conformant profile must define any dependent subset profiles."

All right, in that case I definitely disagree with this resolution.  
The conformance criterion you have stated is vacuous, because any UA  
developer could define any subset he or she wishes, perhaps the empty  
subset, or the subset that includes nothing but the "Document"  
interface with no properties, or the subset that includes the "Node"  
interface. This makes the criterion useless for interoperability. It  
is also not testable. There's no test of this criterion that you  
could write that I couldn't declare inapplicable just by publishing  
some subset profile. Further, your proposal to forbid adding new  
features to profiles because new features can always be defined  
separate from the subset profile or just implemented and not  
specified anywhere.

If you disagree, please tell me what test I could write to verify  
conformance with this requirement.

Please register my disagreement (or better yet, reconsider the issue  
and either remove this requirement or make it meaningful).


>>>> "Conformant user agent must implement DOM Level 3 Event  
>>>> interfaces."
>>>>
>>>> - same comments as above
>>>>
>>> Likewise:
>>> "A conformant user agent must implement DOM Level 3 Events, either
>>> full or
>>> a profiled subset."
>> Same comments as above.
>
> Same response as above.

For the same reasons as above, please register my disagreement or  
reconsider the issue.

>
>> I am satisfied with the specific resolutions for these comments, but
>> I think Appendix B is still problematic. It sounds like the only
>> conformance requirements will be requirements to implement other
>> specs (L3 Core, L3 Events, Window). Maybe that's ok to publish, but
>> it doesn't sound all that useful to have a spec that is just a
>> laundry list of other specs.
>
> When we started our specification, it contained a bit more content.  
> Though
> as you can see with parent-to-child DOM access, these have been  
> moved to
> other (more appropriate) places.  Therefore, having a list of  
> dependent
> specifications is valuable in building a consistent set of profiles  
> upon a
> common framework.  Having a small specification is not a bad thing.

Agreed! But I think it may be that the only remaining meaningful  
normative requirement on user agents is to implement Window. I think  
it might be more helpful to recast CDR as a set of requirements for  
CDR profiles, rather than a set of requirements for user agents. So  
WICD Core would be a CDR-compliant profile, and UAs could conform to  
WICD Core or not - we wouldn't have to worry about whether a UA  
conforms to CDR.

Regards,
Maciej
Received on Monday, 20 March 2006 06:18:45 UTC

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