On 2013-03-03 14:05:32 +0000, John Pryce wrote:
For text2interval(s) where s is a string, here are some possible
upper bounds.
(a) No options. Only the mandatory syntax in 11.11.1 (of draft 7.0).
(b) Permit the "enhanced syntax" in 11.11.1, but tighten up its
specification to disallow many of the possibilities that have been
discussed recently.
(c) Permit arbitrary arithmetic expressions (of some defined syntax)
within s, as in text2interval("0.1+pi") and other more exotic
examples discussed.
K.I.S.S. With respect, I think (c) is way beyond the bounds of
reason, and the discussion of it has only served to confirm this.
IMHO, implementation-defined extensions should be allowed. As they
are extensions, they don't need to be specified.
The number (point) representation is not the only one involved.
For instance, an implementation may need to represent some specific
form of intervals...
(3) Other ways of denoting an interval (besides inf-sup and
mid-rad) may be provided.
[...]
- (3) clearly opens "an arbitrary can of worms". So either delete
it, or restrict to one or two specified alternatives, e.g. §6.4
"Uncertain numbers" and/or §6.5 "Exact numbers" in Arnold Neumaier's
Vienna proposal. (Richard, you can get this from the position papers
on the P1788 web site.)
I disagree. Some alternate form may be useful, e.g. triplex, or a
sum of intervals (which could be seen as some form of generalization
of floating-point expansions to interval arithmetic, for instance).
And I repeat: they would just be extensions and would not have to be
specified by P1788.