Look into using library for handling variables

[buggymcbugfix]

This came up at work today and seems interesting:
http://hackage.haskell.org/package/unbound-generics

I'm not sure if it would make sense for us to use this, but I'd like to look into that since it might allow us to outsource some infrastructure.

[brendanzab]

I started off with my own binding library inspired by unbound, called Moniker. I've now decided to move away from it to 'semantic type checking'in brendanzab/rust-nbe-for-mltt. You can see more of my reasoning at pikelet-lang/pikelet#181. If you were to use a variable binding library, I'd recommend using Bound - it uses a more efficient strategy for name binding, but yeah - would still give semantic type checking a good look, especially if you are wanting to move towards dependent types in the future!