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Re: Adopting the media accessibility requirements

From: Karl Dubost <karl+w3c@la-grange.net>
Date: Sun, 31 Oct 2010 09:51:57 -0400
Message-Id: <DF595120-768B-416C-8FB1-979A22450131@la-grange.net>
Cc: HTML WG <public-html@w3.org>
To: Jonas Sicking <jonas@sicking.cc>

(just a reminder)

Le 30 oct. 2010 à 15:55, Jonas Sicking a écrit :
> What is being unclear to me in this whole discussion, possibly because
> different people have different interpretations, is what "must" and
> "may" etc mean in this context.

    "Use a consistent style for conformance 
    requirements and explain how to distinguish 
    --- http://www.w3.org/TR/qaframe-spec/#consistent-style

The terms can be defined as long as there is a shared agreement on their meaning and the style is consistent. The danger of MUST and MAY for users, contents, etc. is that the terms meaning is loaded by RFC2119 usage. We had a lot of discussions about that when writing the QA Framework.

    6. Guidance in the use of these Imperatives

       Imperatives of the type defined in this memo must
       be used with care and sparingly. In particular,
       they MUST only be used where it is actually
       required for interoperation or to limit behavior
       which has potential for causing harm (e.g.,
       limiting retransmisssions) For example, they must
       not be used to try to impose a particular method
       on implementors where the method is not required
       for interoperability.
    --- http://www.ietf.org/rfc/rfc2119.txt

Using MUST for user requirements is often blurring the discussion. It's better to use MUST for software implementations. That said, you can still conformance requirements expressed in prose or formal language when necessary. 

Karl Dubost
Montréal, QC, Canada
Received on Sunday, 31 October 2010 13:52:18 UTC

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