Variable natToString : nat -> string. Extract Inlined Constant natToString => "natToString".
Instance NatToStringInstance : ToString nat := { toString := natToString }.
-(* Figure 7: production κ, ι *)
Inductive Kind : Type :=
| KindStar : Kind (* ★ - the kind of coercions and the kind of types inhabited by [boxed] values *)
| KindArrow : Kind -> Kind -> Kind (* ⇛ - type-function-space; things of kind X⇛Y are NOT inhabited by expressions*)