[coldtea]

>And some languages are allowed to use FFI to make their impl faster. There's some rule about this that I don't understand, but oh well. It's all for fun, not serious.

Actually it's pretty easy: if you can write a faster version in any language, given whatever is there in the language, even if it's c implemented standard library stuff, do it.

The implementations are not meant to be final -- people can contribute faster ones.