Re: Range excluding 0.0

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Sat, 29 Aug 2009 16:51:56 -0400, John B. Matthews wrote:

> In article <1j57hiw.vmezw81qexbi6N%csampson@inetworld.net>,
>  csampson@inetworld.net (Charles H. Sampson) wrote:
> 
> [...]
>>      This is not just theoretical musing.  I currently work in the 
>> world of compasses, so a range of the form [0.0 .. 360.0) is quite 
>> natural. (That notation is neither mathematical nor Ada.  I hope its 
>> meaning is clear.)
> 
> I'd be torn between these, but wrapping around the right end would be a 
> problem with either:
> 
> subtype Heading is Float range 0.0 .. 360.0;
> subtype Heading is Float range 0.0 .. Float'Pred(360.0);
> 
> If the range were intended to model a craft's heading (perhaps in 
> degrees, minutes & seconds), I'd be tempted to consider a modular type:

Still using non-metric units, guys? (:-))
 
> type Heading is mod 360 * 60 * 60;
> 
> This might make a relative change in heading easier to implement.

   Second : constant := 1.0 / (60.0 * 60.0);
   type Heading is delta Second range 0.0..360.0 - Second;

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de