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Re: int2interval, frac2interval, rat2interval

On Apr 20 2012, Vincent Lefevre wrote:


I think it could be (b) with very simple rules:
 * the type contains integers, and possibly other values (numeric
   or not).
 * int2interval(i) is specified on integer values by P1788.
 * On other values, int2interval(i) returns NaI (if accepted for
   other constructors).


So far, fine.


Note: in practice, the type can provide infinities, but they should
be seen as other values, because infinities cannot be produced in a
correct integer expression.


Er, why not?  It is as easy to specify and produce integral infinities
as rational / real / floating-point ones.  Not all languages use ISO
C's aberrant numeric type model.

Regards,
Nick Maclaren.