Re: Dimensionality Checking (Ada 20XX)

["Mark Lundquist" <no.spam@getalife.com>]

"Nick Roberts" <nickroberts@adaos.worldonline.co.uk> wrote in message
news:9vb98r$e9g47$1@ID-25716.news.dfncis.de...
> "Mark Lundquist" <no.spam@getalife.com> wrote in message
> news:Nn7S7.44589$ER5.535249@rwcrnsc52...
>
> > > > I'm not sure quite what you're getting at there, but it sounds like
it
> > > might
> > > > be related to an issue I've been thinking about, which is that these
> > units
> > > > currently would not be able to work with "quasi-numeric"
abstractions
> > such
> > > > as people define for things like rational numbers,
infinite-precision
> > > > arithmetic, etc.
> > > > ...
> > >
> > > Correct. (The example presented to me was Ada.Calendar.Time).
> >
> > There you go... Calendar.Time is a perfect example.
>
> Yes. It is important to keep what is being proposed in perspective. If it
> has any merit at all, it will be limited. Nevertheless, I do believe it
has
> merit. (Remember, we are not trying to solve all the world's problems at a
> single stroke ;-)

Right.  Private numeric types are an orthogonal problem.  Only, if that
feature were added and so were unit-awareness, then it would make sense for
the two features to play together, that's all.  My intuition is that there
are no obstacles to getting unit-awareness to work with private numeric
types that wouldn't already have had to be overcome just to get private
numeric types to work in the language at all.

And I think those obstacles would be considerable... if you can't figure out
how to get literals and constrained subtypes that make sense, then it's
hardly worth talking about.  It would probably take someone smarter than me
to figure those out.  But like I said, I haven't given it a whole lot of
thought...

--mark
--

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