Re: Expressing physical units

[Jacob Sparre Andersen <sparre@nbi.dk>]

Hyman Rosen wrote:
> Jacob Sparre Andersen wrote:

> > It should be noted that my analysis was tied rather strongly to
> > Ada, and a more relaxed programming language might be able to do
> > something that would be sufficiently close to full compile-time
> > unit checking.
> 
> C++ can do full compile-time unit checking with no runtime overhead
> as long as all units needed by the program are known at
> compile-time.

Yes.  I am aware of that. - And that it is a much more elegant
solution than the one I use do to do the same thing in Ada (in Ada you
actually have to specify _each_ of the units you are going to use
explicitly).

> The technique uses templates, requires automatic instantiation of
> templates for usability (and so cannot be done in Ada),

Yes.

I don't understand C++ templates well enough to be able to see if it
is realistic to copy enough of it to Ada, to allow the easier handling
of compile-time unit checking available in C++.  I am afraid it would
give too many unwanted possibilities in Ada, but it is very tempting.

> and was published in Barton & Nackman, _Scientific and Engineering
> C++_. I've often posted the technique, but here goes again, in a
> simplified version:

[...]

Thanks.

Jacob
-- 
�USA fights for the right of the individual.�
�Yes.  Those of the individual George W. Bush.�
                                     -- with thanks to Olfax