check swift version. errors, in playground all's good.

Yes, it would be nice to specify that the "first" bit is the least significant one

Yep, I guessed wrong and had to flip my masks as well. It might be worth at least just mentioning in the description that the "first four bits" means the rightmost ones, or just say that when considering the bits of the package, you work from the right. Otherwise, this is awesome.

That's right, I don't know how that one skipped my view, It's changed and I also added a CoffeeScript version! Sorry! Thanks for informing me!