Use of SHOULD (Last Call comment on WAI-ARIA)

Hi,

In a number of places in the WAI-ARIA draft, requirements use the level 
SHOULD but it isn't clear why they are not MUST. In particular:

 * Why is the use of abstract roles disallowed only as a SHOULD NOT? When 
   would it be ok to use them? (This requirement is present twice, once in 
   4.2.1. Abstract Roles and once in 4.3.1. Base Types. It is also given 
   explicitly for each abstract role, e.g. in the section named "composite 
   (abstract role)".)

 * Why are authors only required to specify required attributes as a 
   SHOULD? When would it be ok to omit required attributes?

 * Why is the requirement that the parent element be present only a 
   SHOULD? When is it ok to nest elements in ways that conflict with the 
   definitions in the spec?

Cheers,
-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

Received on Thursday, 2 April 2009 03:11:40 UTC