Thanks, this is what I was hoping someone would write! I searched around a bit about HKT's and although I can't say I understand them, I can see how the abilit

Thanks, this is what I was hoping someone would write! I searched around a bit about HKT's and although I can't say I understand them, I can see how the ability to do something like provide a constructor over a type could be useful. It feels like it has a lot of use in writing very general-purpose libraries, or perhaps a DSL that can map to a wide variety of different types. Interesting!