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

Eliot Lear <lear@cisco.com> Tue, 29 March 2016 21:09 UTC

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Subject: Re: Fuzzy words [was Uppercase question for RFC2119 words]
To: Brian E Carpenter <brian.e.carpenter@gmail.com>, "Scott O. Bradner" <sob@sobco.com>, Barry Leiba <barryleiba@computer.org>
References: <20160320223116.8946.76840.idtracker@ietfa.amsl.com> <949EF20990823C4C85C18D59AA11AD8BADEAFFC7@FR712WXCHMBA11.zeu.alcatel-lucent.com> <CA+9kkMCsT43ZCSdq8gdKXu1k4pJgbf0ab5tE=dDiFfrTT2gtkA@mail.gmail.com> <949EF20990823C4C85C18D59AA11AD8BADEB0D16@FR712WXCHMBA11.zeu.alcatel-lucent.com> <56F79D05.8070004@alvestrand.no> <326E6502-28E5-4D09-BB99-4A5D80625EB0@stewe.org> <56F88E18.2060506@it.aoyama.ac.jp> <20160328104731.GO88304@verdi> <CALaySJ+hYMMsKE7Ws-NJbyqH55E-mQM-duTEcJGc0TWvTP88Ew@mail.gmail.com> <20160328132859.GP88304@verdi> <28975138-9EA1-4A9F-A6C0-BC1416B8EA44@sobco.com> <CALaySJJkNj2jfm0gJpuDzq8oFDjTNn-uQ5MHdmEOLwTiFZUyQQ@mail.gmail.com> <8975F15F-5C4C-4D02-98CD-BF4FDF104D35@sobco.com> <56F98CD1.10706@gmail.com>
From: Eliot Lear <lear@cisco.com>
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Date: Tue, 29 Mar 2016 22:43:53 +0200
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On 3/28/16 9:58 PM, Brian E Carpenter wrote:

> Where we can get into real trouble is if a spec contains should, recommended,
> may and optional *plus* other non-categorical (fuzzy) words like ought,
> encourage, suggest, can, might, allowed, permit (and I did not pull those
> words out of the air, but out of draft-hansen-nonkeywords-non2119). What do
> they mean? It can be very unclear. If a node receives a message containing
> an element covered in the spec by "allowed" instead of "OPTIONAL", is the
> receiver supposed to interoperate or to reject the message?

Yes, this.  There seems to be a sort of MUSTSHOULDMAYphobia.  The
contortions some people will go through to avoid the words when that is
what they mean is, at times, hilarious; but at other times harmful to
interoperability.

Eliot