NotAbstract example from Universal and Existential Types in ReasonML blogpost

NotAbstract.re

/* link to playground: https://bit.ly/2uCBISK */
module type Animal = {
  type t = string;
  let make: (string) => t;
  let sprint: (t) => string;
};

module Animal: Animal = {
  type t = string;
  let make = (name) => name;
  let sprint = a => {j|$a is running!|j};
};

let pwned = "pwned";
Js.log(Animal.sprint(pwned));