Implementing Haskell's Type-Level Quicksort in D

[bearophile]

>> alias One = Typedef!(Succ!Zero);
>> alias Two = Typedef!(Succ!One);
>> alias Three = Typedef!(Succ!Two);
>> alias Four = Typedef!(Succ!Three);
>
> Note that you need a "cookie" for those Typedefs, otherwise 
> they are not useful.

They are different types, so my comment is wrong :-) I don't 
understand why you have used Typedef there.

Bye,
bearophile