Re: Comments on clause 9. Recommended operations in draft 1.6.0

[David Hough 754R work <754r@xxxxxxxxxxx>]

> Should we say something about conformance
> not just in a particular radix, but also in a particular format?

In my proposal
 
 http://754r.ucbtest.org/msc-ballots/formats.pdf

I define conformance to the standard, and a conforming implementation of a 
supported
arithmetic format, and a conforming implementation of a supported interchange 
format.

I have wrestled with the question of how to extend the is754version1985 and
is754version2008 predicates in a useful direction to tell more about which 
language
types map to which 754R formats, but gave up as it's too complicated in general
to be inventing at this point.    Different languages might have only binary,
only decimal, binary or decimal as a compile option, binary or decimal as a 
run-time
option, binary and decimal simultaneously available as separate types, binary 
and decimal 
simultaneously available in the same types...

Perhaps the recommendation should be that languages provide a means of 
determining
the mapping between a particular program variable and a supported 754R format
which might be static or dynamic according to the language.     One would want 
to
know whether it's arithmetic, interchange, or both.   How are language-defined
extended/extensible and implementation-defined extended/extensible to be 
identified?

For some languages this will all be fixed because there is only one 
floating-point
type or only one type; for others it will all be implementation-defined.
What specification is both specific enough to be useful and flexible enough to 
encompass all possibilities?

The more global conformance question is again at the language level, for 
languages
that define conformance to 754 or 754R; then is754version2008() tells whether 
conformance to a language revision that supports 2008 is enabled and similarly 
for 1985.
In either case the exact meaning depends on the language and doesn't really
seem to be something that could be used in a portable way across languages.