If you want to have fun, I also have a small tutorial on how to make a typesafe printf function with GADTs (and that technique is actually used in the OCaml std

If you want to have fun, I also have a small tutorial on how to make a typesafe printf function with GADTs (and that technique is actually used in the OCaml stdlib!) https://drup.github.io/2016/08/02/difflists/ https://drup.github.io/2016/08/02/difflists/ I also have some slides (more entertaining and probably better introduction) here: https://www.irif.fr/~gradanne/papers/gadts.pdf https://www.irif.fr/~gradanne/papers/gadts.pdf