Re: Fuzzy words [was Uppercase question for RFC2119 words]

Dave Cridland <dave@cridland.net> Wed, 30 March 2016 07:24 UTC

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Date: Wed, 30 Mar 2016 08:24:53 +0100
Message-ID: <CAKHUCzxi-h82mGSLAmHP_k=haLPoXawgL0P=aBF=v25yxvq7KA@mail.gmail.com>
Subject: Re: Fuzzy words [was Uppercase question for RFC2119 words]
From: Dave Cridland <dave@cridland.net>
To: Brian E Carpenter <brian.e.carpenter@gmail.com>
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Cc: IETF discussion list <ietf@ietf.org>, "Heather Flanagan \(RFC Series Editor\)" <rse@rfc-editor.org>, rtcweb@ietf.org, IESG <iesg@ietf.org>, John C Klensin <john-ietf@jck.com>, Barry Leiba <barryleiba@computer.org>
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On 30 March 2016 at 00:46, Brian E Carpenter <brian.e.carpenter@gmail.com>
wrote:

> On 30/03/2016 05:34, John C Klensin wrote:
> >
> >
> > --On Tuesday, March 29, 2016 08:58 +1300 Brian E Carpenter
> > <brian.e.carpenter@gmail.com> wrote:
> >
> >> ...
> >> The other words (must, shall, required, not) mean what they
> >> always mean. The only argument for upper-casing them is
> >> aesthetic symmetry. If a spec uses alternatives like
> >> mandatory, necessary or forbidden, they are just as powerful.
> >> ...
> >
> > Actually, when 2119 is referenced, Section 6 attaches particular
> > interoperability semantics to MUST, SHALL, etc., that are not
> > part of the plain-English meaning of those words.  Section 6
> > seems to be ignored most of the time but cited when it supports
> > an axe someone wants to grind about use of conformance language.
>
> My claim is that even section 6 does *not* change the meanings
> of the categorical words in a spec. If it says that something
> must or must not happen, either the statement is redundant or
> it is essential for interoperability, whether it's written
> in upper case Courier New or in runes.
>
>
I should think you must realise that shall not always be the case.


> But it doesn't matter. It's the SHOULDs and MAYs that require
> precision in their use.
>
>       Brian
>
>