hirrolot

trait Interp {
    type Repr<T>;

    fn lit(i: i32) -> Self::Repr<i32>;
    fn add(a: Self::Repr<i32>, b: Self::Repr<i32>) -> Self::Repr<i32>;
}

struct Eval;

impl Interp for Eval {

hirrolot

(* The syntax of our calculus. Notice that types are represented in the same way
   as terms, which is the essence of CoC. *)
type term =
  | Var of string
  | Appl of term * term
  | Binder of binder * string * term * term
  | Star
  | Box

and binder = Lam | Pi