On 30/08/2011, at 12:44 PM, Eric Burger wrote: > Yes, and... > > I would offer that for most cases, If Y then MUST X or If Z then MUST NOT X > *are* what people usually mean when they say SHOULD. In the spirit of Say > What You Mean, a bare SHOULD at the very least raise an ID-nit, suggesting to > the author to turn the statement into the if Y then MUST X or if Z then MUST > NOT X form. Being pedantic and pedagogic: > SHOULD send a 1 UNLESS you receive a 0 > really means > UNLESS you receive a 0, one MUST send a 1. > > My vision of the UNLESS clause is not necessarily a protocol state, but an > environment state. These are things that I can see fit the SHOULD/UNLESS > form: > SHOULD send a 1 UNLESS you are in a walled garden > SHOULD flip bit 27 UNLESS you have a disk > SHOULD NOT explode UNLESS you are a bomb > are all reasonable SHOULD-level statements.
If this is the intent, I'd say it should (ahem) really be MUST... UNLESS. SHOULD... UNLESS will lead to people misreading it. > Unless of course one considers us the Protocol Nanny's(tm) - if do not do a > SHOULD, we will send you to bed without your treacle! I.e., there IS NO > DISTINCTION BETWEEN A BARE SHOULD AND A MAY. +1 > > On Aug 29, 2011, at 9:47 PM, ned+i...@mauve.mrochek.com wrote: > >>> Hi - >> >>>> From: "Eric Burger" <eburge...@standardstrack.com> >>>> To: "Narten Thomas" <nar...@us.ibm.com>; "Saint-Andre Peter" >>>> <stpe...@stpeter.im> >>>> Cc: "IETF discussion list" <ietf@ietf.org> >>>> Sent: Monday, August 29, 2011 3:08 PM >>>> Subject: Re: 2119bis >>>> >>>> I would assume in the text of the document. This paragraph is simply an >>>> enumeration of Burger's Axiom: >>>> For every SHOULD, there must be an UNLESS, otherwise the SHOULD is a MAY. >> >>> I disagree. >> >> I concur with your disagreement. SHOULD should *not* be used when the >> list of exceptions is known and practically enumerable. >> >>> If the "UNLESS" cases can be fully enumerated, then >>> "SHOULD x UNLESS y" is equivalent to "WHEN NOT y MUST X." >>> (Both beg the question of whether we would need to spell out that >>> "WHEN y MUST NOT X" is not necessarily an appropriate inference.) >> >>> RFC 2119 SHOULD is appropriate when the "UNLESS" cases are >>> known (or suspected) to exist, but it is not practical to exhaustively >>> identify them all. >> >>> Let's not gild this lily. >> >> +1 >> >> Ned >> _______________________________________________ >> Ietf mailing list >> Ietf@ietf.org >> https://www.ietf.org/mailman/listinfo/ietf > > _______________________________________________ > Ietf mailing list > Ietf@ietf.org > https://www.ietf.org/mailman/listinfo/ietf -- Mark Nottingham http://www.mnot.net/ _______________________________________________ Ietf mailing list Ietf@ietf.org https://www.ietf.org/mailman/listinfo/ietf
