Dtype [(["a"; "b"],"prod",[("Pair",[Tvar "a"; Tvar "b"])])]

Dtype
  [(["a"],"list",
    [("Cons",[Tvar "a"; Tapp [Tvar "a"] "list"]); ("Nil",[])])]

Dlet (Pvar "HD")
  (Fun "x1"
     (Mat (Var "x1")
        [(Pcon "Nil" [],Raise Bind_error);
         (Pcon "Cons" [Pvar "v2"; Pvar "v1"],Var "v2")]))

Dlet (Pvar "TL")
  (Fun "x1"
     (Mat (Var "x1")
        [(Pcon "Nil" [],Raise Bind_error);
         (Pcon "Cons" [Pvar "v2"; Pvar "v1"],Var "v1")]))

Dletrec
  [("APPEND","v3",
    Fun "v4"
      (Mat (Var "v3")
         [(Pcon "Nil" [],Var "v4");
          (Pcon "Cons" [Pvar "v2"; Pvar "v1"],
           Con "Cons"
             [Var "v2";
              App Opapp (App Opapp (Var "APPEND") (Var "v1"))
                (Var "v4")])]))]

Dletrec
  [("REV","v3",
    Fun "v4"
      (Mat (Var "v3")
         [(Pcon "Nil" [],Var "v4");
          (Pcon "Cons" [Pvar "v2"; Pvar "v1"],
           App Opapp (App Opapp (Var "REV") (Var "v1"))
             (Con "Cons" [Var "v2"; Var "v4"]))]))]

Dlet (Pvar "REVERSE")
  (Fun "v1"
     (App Opapp (App Opapp (Var "REV") (Var "v1")) (Con "Nil" [])))