On 30 March 2016 at 00:46, Brian E Carpenter <brian.e.carpenter@xxxxxxxxx> 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@xxxxxxxxx> 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