Re: Efficiency of code generated by Ada compilers

[Robert A Duff <bobduff@shell01.TheWorld.com>]

csampson@inetworld.net (Charles H. Sampson) writes:

> <tmoran@acm.org> wrote:

>>    Bearing := (Bearing + Turn_Angle) mod 360;
>
>      I'd be interested in hearing reactions to something I did. ...

>      I then overloaded "+" and "-" for (Bearing, Turn_Angle) arguments
> and Bearing return value.  In those functions is where the mod 360
> occurred.  (Actually, mod 360.0, as it were.)
>
>      There were two advantages to doing that.  The more important was
> that previously both of the kinds of values were being represented as
> subtypes of Long_Precision and programmers would occasionally
> interchange them and cause big debugging problems.  The second was
> removing the "mod" from sight, which allowed the programmers to simply
> think of taking a bearing, turning an angle, and getting the resulting
> bearing, without worrying about all the niceties that might be going on
> inside "+".

Sounds to me like a good way to do things.  It would still be a good
idea if you called it "Turn_Left" or something like that, instead
of "+".  But I don't object to "+".

I object to having built-in support for angle arithmetic in the
language, though.

Did you eliminate meaningless ops like "*"?  You could do that
by making the types private, but then you lose useful things
like literal notation.  Or you could declare "*" to be
abstract, which is an annoyance, but might be worth it.

- Bob