Re: P1788 1.8 "Language considerations"
On 2012-12-07 12:28:52 +0000, N.M. Maclaren wrote:
> On Dec 7 2012, Vincent Lefevre wrote:
> >>
> >> Specifically, a language shall specify a set of bindings to the
> >
> >I would say "a language or implementation" because the implementation
> >could be just a library.
>
> A good point. "Language or other binding mechanism" would be better,
> as there need be no associated implementation.
Yes (by "no associated implementation", I assume that you mean that
the implementation is implied by the language itself).
> >> operations specified in this standard, with the functionality and
> >> semantics as specified here. These may be specified as bindings
> >> to built-in operations, library procedures or otherwise.
> >>
> >> Code which is syntactically the same as code operating on
> >> approximate real numbers, but operating on intervals, shall obey
> >
> >I don't think this makes sense (perhaps except for OO languages).
>
> Well, that includes C, C++, Fortran, Matlab, Mathematica etc.
I meant that the phrasing is meaningless to me. But I think I now
understand these two lines with your additional comments.
> Also, some languages and/or implementations may have an option to
> treat declared reals as intervals. I agree that the wording isn't
> good, but I can't think of a better.
If you mean that a language must provide the same syntax for FP
(or other real-approx arithmetic) and for intervals, I disagree.
For instance, in C, one can add 2 FP numbers with "a + b", but
without a C extension, interval computations would need to be
done by something like function calls: interv_add(a,b).
If you mean that this is optional, you could say something like:
"In languages where code can be syntactically the same as code
operating on approximate real numbers, but operating on intervals
[...]". The remaining is now not clear to me.
--
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)