Promotion rules ... why no float?

[Lodovico Giaretta via Digitalmars-d]

On Wednesday, 7 September 2016 at 14:46:46 UTC, Sai wrote:
> I suspected the same, most of the CPUs support fast floating 
> point operations anyway (with FPUs), shouldn't take a lot more 
> time than doing integer arithmetic. Unless we are targeting 
> 8bit avr or something similar.
>
> And precision argument doesn't seem strong either, since, which 
> is more precise 3/7 = 0 or 0.4285 ?
>
> I am not suggesting we change the promotion rules now, most 
> likely never going to happen. But I am trying to find a good 
> rationale for the existing rules and unable to find a good one.

x == x/k + x%k

The above formula holds in integer arithmetic. It is fundamental 
in many operations. You cannot achieve the same with floating 
point calculations. Whenever you do batch jobs, dividing you work 
into groups (and you don't really want 2.3 groups) and whenever 
you iterate the digits of a number, implicit floating point 
conversions can really hurt.

I think the current state of affairs is fairly good. Adding 
implicit conversions would make it worst. What would probably 
make it better (but can't be changed now) is having two distinct 
operators, one for integer division and one with implicit 
floating point conversions.