Re: Motions 5 and 6 under discussion --
P1788 members
Looking at the concepts that underlie a "standard", I feel, now we
are getting down to details, that P1788 needs to agree what is meant
by "conformance". I hope, as far as possible, we shall use the same
terms and definitions (maybe reworded for extra clarity) as does 754.
Here is what I understand from reading IEEE Std 754-2008.
"Environment", apparently synonymous with "programming environment",
seems to be an undefined term.
2.1.2 and 2.1.33 define "arithmetic" and "interchange" formats, with
more in 3.1.1 (and of course the gory details later).
Definition 2.1.52 says
"supported format: A floating-point format provided in the
programming environment and
implemented in conformance with the requirements of this standard. ..."
3.1.2 says
(A) "A programming environment conforms to this standard, in a
particular radix, by implementing one or more
of the basic formats of that radix as both a supported arithmetic
format and a supported interchange format."
So apparently, "conforming" is something an environment does.
Previous to that it says
- some things a conforming implementation of any supported format
shall "provide";
- ditto, any supported arithmetic format;
- ditto, any supported interchange format;
"Implementing" a format is not defined, nor is "providing" that
format, and they have slightly different meanings.
And in 1.5 we read
(B) "Conformance to this standard is a property of a specific
implementation *of* a specific programming
environment, rather than of a language specification. "
I think I understand all this -- though (B) slightly contradicts (A)
-- except for the starred "of" in the previous sentence, which I have
asked Dan Zuras to clarify for us.
I had an attack of cold feet, wondering if we can vote on motion 6
before we have thrashed out the meanings, in the P1788 context, of
these crucial terms
environment, implementation, provide, support, conform.
However, my feeling is that we can and should so vote, and should
discuss these terms as part of voting on the relevant chunks of
standard text (which I am having a go at constructing).
My two questions:
- Do you agree with the previous sentence?
- Should we take the wording of 754 on these matters, with minor
changes? Or can we do better, e.g. by merging the ideas of 1.5 and
3.1.2 into one section? I find 754 a bit "round the houses" on these
ideas, and had to jump around the text to get a grip on them.
Best wishes
John Pryce