Why aren't Ranges Interfaces?

[Jack Stouffer via Digitalmars-d-learn]

On Friday, 26 June 2015 at 19:40:41 UTC, rsw0x wrote:
> On Friday, 26 June 2015 at 19:26:57 UTC, Jack Stouffer wrote:
>> Thanks for the reply! I understand the reasoning now.
>>
>> On Friday, 26 June 2015 at 18:46:03 UTC, Adam D. Ruppe wrote:
>>> 2) interfaces have an associated runtime cost, which ranges 
>>> wanted to avoid. They come with hidden function pointers and 
>>> if you actually use it through them, you can get a 
>>> performance hit.
>>
>> How much of a performance hit are we talking about? Is the 
>> difference between using an interface and not using one 
>> noticeable?
>
> It can be in a tight loop.
>
> http://eli.thegreenplace.net/2013/12/05/the-cost-of-dynamic-virtual-calls-vs-static-crtp-dispatch-in-c
>
> this is for C++, but it applies directly to D. Interestingly, 
> CRTP is a gigantic C++ hack that D gets for free with alias 
> this.

In my code I need to use polymorphism. But, if I replace the code 
for my interface inheritance with an inherit of an class that 
implements empty methods and my methods just override the empty 
ones I get an essentially free performance boost 0_0? Good to 
know; thanks for the link.