Re: Conformance and Deprecated Features

On Tue, 29 Jan 2002, Karl Dubost wrote:
> At 11:39 -0800 2002-01-29, Rob Lanphier wrote:
> >Deprecated != Withdrawn
> >
> >Deprecated means "hey content authors: this was probably a bad idea, and
> >there are better ways of doing this.  Please don't continue to generate
> >content in this format".  Hopefully, deprecated features can fade into
> >obscurity, at which point, it becomes *safer* to withdraw them.  However,
> >it's always very dangerous to withdraw features, for reasons already
> >stated.
>
>
> So a good conformance clause could say:
> 	A  compliant  user agent to the version X+1 SHOULD implement
> deprecated features of version X.
> 	A compliant authoring tool to the version X+1 MUST NOT
> implement deprecated feature of version X.
>
> Does it make sense?

Yeah, that does, with minor caveats.

On the user agent side, I'd go further and state that the user agent to
the version X+1 MUST implement deprecated features. One of the biggest
advantages of putting content in a standard format is that it's a means of
futureproofing your work.  If a "fully conformant" user agent can take the
MIME type for your "futureproof" document and return errors, that doesn't
really make it futureproof.

The idea that a conformant authoring tool "MUST NOT" implement the
deprecated feature has to be carefully worded.  A document generated for
usage in X user agents may need to use features that are deprecated in
X+1.  A better restriction is that a fully X+1 conformant user agents MUST
be configurable to generate X+1 content that doesn't rely on deprecated
features.

Rob

Received on Wednesday, 30 January 2002 01:19:44 UTC