Re: Another Idea for Ada 20XX

["Mark Lundquist" <mlundquist2@attbi.com>]

"Philip Anderson" <phil.anderson@amsjv.com> wrote in message
news:3C0F8E75.4F5CB3B8@amsjv.com...
> Mark Lundquist wrote:
> >
> <snip>
> > Units are unlike types in that they are optional (think about it, what
units
> > would you give for Pi?).
> <snap>
>
> I don't think units are "optional", although they may be dimensionless,
> ie just numbers like Pi.

Eh?  OK, so I'll ask again, what units would you give for Pi?

>  Note that radians, being a ratio, are actually
> dimensionless.

No, they are not!

(BTW rate is also the ratio of distance/time, and of course rate isn't
dimensionless -- any more than radians are!)

The dimension of angle is distance/distance.  (I'm not making this up -- the
SI define radians in terms of meter*(meter**-1)).  That's why when you
multiply a distance by an angle, you get a distance.  But if you were to
multiply a mass by an angle, you do not get a mass (which would make it a
unit conversion), but something whose units would be "kg-radians".  (What
use would that have?  Beats me, for all I know there might be one... I'm a
physics 'tard, my wise-ass PhD little brother got all the physics genes :-)
:-)

Dimensionless numbers do not change the units when you multiply them, that's
the difference.  No measurement is dimensionless.

Cheers,
Mark