3.11  Exemples

# type_check (Const (Int 3));;

it : int

- : unit = ()

# type_check (Const (Float 3.2));;

it : float

- : unit = ()

# type_check (Abs ("x", Var "x"));;

it : ('a -> 'a)

- : unit = ()

# type_check (Abs ("x", Pair(Var "x", Var "x")));;

it : ('a -> ('a * 'a))

- : unit = ()

# type_check (Letin ("f", Abs ("x", Pair(Var "x", Var "x")),

                   ( Pair ((App (Var  "f", Const (Int 3))),

                           (App (Var "f", Const (Float 3.14)))))));;

it : ((int * int) * (float * float))

- : unit = ()

# type_check (App (Var "*", Pair (Const (Int 3), Const (Float 3.1))));;

Type clash between int and float

Exception: Failure "type_check".

# type_check (Cond (

     App (Var "=", Pair(Const(Int 0), Const (Int 0))),

     Const(Int 2),

     Const(Int 5)));;

it : int

- : unit = ()

# type_check (

   Letrecin ("fact",

     Abs ("x",

          Cond (App (Var "=",Pair(Var "x",Const(Int 1))),

                Const(Int 1),

                App (Var "*",

                     Pair(Var "x",

                          App (Var "fact",

                               App (Var "-",Pair(Var "x",Const(Int 1) ))

                              )

                         )

                    )

               )

         ),

     App (Var "fact", Const (Int 4))));;

it : int

- : unit = ()