Thanks, this is what I was hoping someone would write!<p>I searched around a bit about HKT&#x27;s and although I can&#x27;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!