Code speed

[Ary Borenszweig]

Don wrote:
> 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.

But if you do a static import the whole module gets linked in, right?

My point is, if you are going to pow, you will need std.math, so it'll 
always be a burden to import it by hand when using it. ^^