setDec and forbidden interval/decoration combinations
Vincent Lefèvre suggested the following:
> - setDec(Empty, dx) where dx is one of def, dac or com returns Empty_trv.
> - setDec(x, com), for any unbounded x, returns Entire_dac.
That's the version I prefer, as opposed to introducing NaI
all over the place.
I seem to recall a principle that NaI should only be returned
by constructors, i.e. when new intervals are introduced into
an interval computation.
Initially constructors were also the only operations that could
lead to exceptions.
Unfortunately we came to realise that there can be other situations
in flavours without Empty or Entire where the set of intervals is
not closed under the available operations, so that at Level 2 we
have to specify SOMETHING to be returned (unless an exception handler
does not return in-line), and NaI is the logical choice, now that we
have it.
Michel.
---Sent: 2013-11-22 15:30:43 UTC