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

"Heather Flanagan (RFC Series Editor)" <rse@rfc-editor.org> Tue, 29 March 2016 14:18 UTC

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Subject: Re: Fuzzy words [was Uppercase question for RFC2119 words]
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: "Heather Flanagan (RFC Series Editor)" <rse@rfc-editor.org>
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Date: Tue, 29 Mar 2016 07:18:32 -0700
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On 3/28/16 12:58 PM, Brian E Carpenter wrote:
> There are times when I think RFC2119 was a really bad idea, despite it having
> become probably the most frequently cited RFC (inside and outside the IETF).
> It seems to create as much confusion as it avoids.
>
> There are four words whose RFC2119 meaning is different from the dictionary
> meaning: should, recommended, may and optional. Having special typography
> for them is useful, because it signals the RFC2119 meanings. But if a spec
> uses, for example, a mixture of SHOULD and should, who knows what the authors
> intended? To that extent, the proposed clarification is helpful.
>
> 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.
>
> So
>> these definitions are only meaningful if the words are capitalized
> can be applied to should, recommended, may and optional if we want,
> but strictly doesn't apply to must, shall, required, not, mandatory,
> necessary, forbidden, need, or any other such words.
>
> 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?
>
> If we are issuing guidance, it should probably include a specific warning
> to use any such fuzzy words with extreme care.

I've been watching this thread and am thrilled to see these
clarifications coming through. Changes to RFC 2219 are a community
decision, not an RFC Editor decision, but the RFC Editor definitely
appreciates consistency and clarity!

-Heather


>    Brian
> On 29/03/2016 03:13, Scott O. Bradner wrote:
>> one minor tweak
>>
>>> On Mar 28, 2016, at 10:09 AM, Barry Leiba <barryleiba@computer.org> wrote:
>>>
>>>> The wishy washy descriptive rather than proscriptive language in the abstract was because I,
>>>> the IESG and the community were not of one mind to say that the use of such capitalized
>>>> terms should be mandatory - quite a few people felt that the english language was at
>>>> least good enough to convey  the writer’s intent without having to aggrandize specific words.
>>>> Thus the abstract basically was saying: if you want to use capitalized words here is a standard
>>>> way to say what they mean
>>> Ah.  Then perhaps the clarification needs to go a little further and
>>> make this clear:
>>> - We're defining specific terms that specifications can use.
>>> - These terms are always capitalized when these definitions are used.
>> these definitions are only meaningful if the words are capitalized
>>
>>> - You don't have to use them.  If you do, they're capitalized and
>>> their meanings are as specified here.
>>> - There are similar-looking English words that are not capitalized,
>>> and they have their normal English meanings; this document has nothing
>>> to do with them.
>>>
>>> ...and I'd like to add one more, because so many people think that
>>> text isn't normative unless it has 2119 key words in all caps in it:
>>>
>>> - Normative text doesn't require the use of these key words.  They're
>>> used for clarity and consistency when you want that, but lots of
>>> normative text doesn't need to use them, and doesn't use them.
>>>
>>> Barry
>>