Re: Question on types conversions - operations

[Robert Matthews <ignored@ramatthews.free-online.co.uk>]

Olivier Scalbert wrote:

> Hello,
> 
> I have the following three types:
>      type Length is new Float;
>      type Time   is new Float;
>      type Speed  is new Float;
> 
> Suppose I need to compute a speed given a length and a time.
> 
>      L: Length := 100.0;
>      T: Time   :=  10.0;
>      S: Speed;
> 
> How to do that ?
> 
> With S := Speed(Float(L) / Float(T)) ? Mmmm ... not nice.
> 
> With S := Speed(L / Length(T)), I am also not satisfy as I convert a
> time in Length ...
> 
> I am sure you have better ideas !
> 
> Good weekend,
> 
> Olivier

For some software with a LOT of maths, I used:
type Working_Real_Type is digits 16;
(which was big enough for the VAX target).
I would convert the various values (typed in a similar
way to your Length, Time etc) to Working_Real_Type
before using them in the equations. It was certainly
not ideal but it seemed a reasonable compromise between
type safety and the maths.

Robert