Re: LC-67 leftover -- MUST use MUST

On Tue, 1 Jul 2003, Dan Connolly wrote:

[ skipped the parts were I introduced explicit context to
  explicitly show that implicit "or else" clause can exist,
  depending on the spec ]

> > And, vice versa, the rollercoaster example can be rephrased as
> >
> > 	Rollercoaster riders are 4 feet tall
>
> But if a kid under 4 feet got on the roller coaster, that would just
> become false.

And if an XML document contains an unquoted value, the "every
attribute value in an XML document is quoted" statement also becomes
false! It is symmetric. For a given context, every definition (X is Y)
can be rephrased as a requirement (X MUST Z) without any objective
harm or gain. So your "or else" criteria does not work well (for me).
I wish it would!

If you argue that an XML document with an unquoted value is not an XML
document (by definition), then I can argue that a rollercoaster rider
under 4 feet is not a rollercoaster rider (also by definition).

> It wouldn't say whose fault it is that it became false. The reason
> we use MUST for agents to make it clear whose fault it is when
> protocols are violated.

I agree. Please note that I am not advocating mandatory use of MUSTs
in every spec. Quite the opposite. I am just saying that without a
context we cannot clearly define the difference between what should be
a definition and what should be a requirement. So, I argue, let's
leave the choice up to the spec authors and mandate only
higher/meta-level things.

> > Overall, it seems to me that the whole issue of "correct" RFC 2119
> > keyword usage is moot. There is no a single correct way and it is
> > not important to have one.
>
> I disagree. There are better ways and worse ways to use RFC2119.

I agree. I doubt a single "best" way can be defined for all
environments though. And that is what some proposed versions of SpecGL
checkpoints may imply or even require, causing the debate.

Alex.

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Received on Tuesday, 1 July 2003 14:25:55 UTC