Re: Dimensionality Checking (Ada 20XX)

[Wes Groleau <wwgrol@sparc01.ftw.rsc.raytheon.com>]

> It's easier to demonstrate than to actually explain. Show me a piece of
> (genuine) Ada code that uses a floating point type to hold values that would
> be usefully made unit-specific, and I'll show you how they certainly could,
> and probably should, be held by a fixed point type instead.

Five million lines of AN/BSY-2 submarine control system ?

> I'm not actually trying to argue that floating point types should never be
> used for non-unitless quantities. All I'm suggesting is that there is no
> practical need to add the unit-specific facility to floating point types.
> Furthermore, I think it would be horribly painful trying to do so (consider
> Ada.Numerics).

Ada was less than five years old when BSY-2 started,
so there were undoubtedly Ada features underused.
(There certainly were Ada features OVERused.)  So
likely some of the floating-point should have been
fixed point.  But don't forget the principal of
orthogonality. One feature shouldn't be artificially
tied to another.  If one numeric type allows units,
all should.

-- 
Wes Groleau
http://freepages.rootsweb.com/~wgroleau