Code speed

[Don]

Ary Borenszweig wrote:
> Don wrote:
>> Lars T. Kyllingstad wrote:
>>> Don wrote:
>>>> bearophile wrote:
>>>>> So far I've just given a light reading of the code. Notes:
>>>>
>>>>> - pow(x, 2) and sqrt(y) can be written as x ^^ 2 and y ^^ 0.5 (but 
>>>>> you have to import std.math anyway, because of a bug).
>>>>
>>>> That's not a bug. It's intentional. x ^^ y will probably always 
>>>> require import std.math, if y is a floating point number.
>>>
>>> Really?  Why is that?  I find that kind of disappointing, I always 
>>> believed it to be a temporary solution.
>>>
>>> I think the inconsistency with the other operators will make this a 
>>> major WTF for people new to the language.  Why should a^^b require an 
>>> explicit import while a*b doesn't?
>>
>> Because pow() for floating point, when implemented properly, is a HUGE 
>> function, that ends up dragging almost all of std.math into the 
>> executable. And I think it's deceptive to do that silently.
>> To make it completely built-in, basically all of std.math would need 
>> to be moved into druntime. Feel free to try to change my mind, of course.
> 
> Is there a better way to do pow() for floating point numbers without 
> importing std.math?
> 
> I see this:
> 
> 1. You want to do x ^^ fp.
> 2. The compiler complains saying "if you want to do that, import 
> std.math. I'm telling you this just to let you know you'll be importing 
> the whole module".
> 
> Alternative 1 for user:
> User says "Ok, I import std.math"
> 
> Alternative 2 for user:
> User says "No way I'm importing std.math just to make a pow. But... I 
> still *need* to make that pow... what is your advice, mr. compiler?"

That's a good point, it should be possible to use a static import as 
well. I do think it's pretty odd to be doing floating point without 
importing std.math, though. I mean, abs() is absolutely fundamental.