"Strong typing vs. strong testing"

[RG]

In article <i92dvd$ada$1 at news.eternal-september.org>,
 "BartC" <bc at freeuk.com> wrote:

> "Thomas A. Russ" <tar at sevak.isi.edu> wrote in message 
> news:ymi1v7vgyp8.fsf at blackcat.isi.edu...
> > torbenm at diku.dk (Torben ZÆgidius Mogensen) writes:
> >
> >> Trigonometric functions do take arguments of particular units: radians
> >> or (less often) degrees, with conversion needed if you use the "wrong"
> >> unit.
> >
> > But radians are dimensionless.
> 
> But they are still units

No, they aren't.

> so that you can choose to use radians, degrees or gradians

Those aren't units either, any more than a percentage is a unit.  They 
are just different ways of writing numbers.

All of the following are the same number written in different notations:

0.5
1/2
50%

Likewise, all of the following are the same number written in different 
notations:

pi/2
pi/2 radians
90 degrees
100 gradians
1/4 circle
0.25 circle
25% of a circle
25% of 2pi

See?

rg