Fix for let rec, currently not implemented

lib/miniFun/TypeChecker.ml

@@ -251,7 +251,16 @@ let rec evaluate_type_polimorphic program (env: env) level =
     let* var_ty = evaluate_type_polimorphic xval env (level + 1) in
     let generalized_ty = generalize level var_ty in
     evaluate_type_polimorphic rest (VariableMap.add x generalized_ty env) level
-  | LetFun (_f, _xs, _typef, _fbody, _rest) -> failwith "Not Implemented"
+  | LetFun (f, xs, _typef, fbody, rest) ->
+    let* _ = Error (`RecusrionsNotImplemented "Let Rec is not implemented.") in
+    let tmp_type_f = VariableTypeP (ref (Unbound (new_global_id (), level))) in
+    let new_env = VariableMap.add f tmp_type_f env in
+    let param_type = VariableTypeP (ref (Unbound (new_global_id (), level))) in
+    let fn_env = VariableMap.add xs param_type new_env in
+    let* body_type = evaluate_type_polimorphic fbody fn_env level in
+    let* _ = unify tmp_type_f body_type in
+    evaluate_type_polimorphic rest (VariableMap.add f tmp_type_f env) level
+
 
 (* -------------------------------------------------------------------------- *)
 
@@ -419,3 +428,10 @@ let typecheck_polymorphic (program: t_exp)
   in
   let generalized_ty = generalize (-1) type_program in
   Ok (generalized_ty)
+
+let typecheck_polymorphic_unbound (program: t_exp)
+  : (type_f, [> typechecking_error]) result =
+  global_type_id := 0;
+  let* type_program = evaluate_type_polimorphic program VariableMap.empty 0 in
+  let generalized_ty = generalize (-1) type_program in
+  Ok (generalized_ty)

lib/miniFun/TypeChecker.mli

@@ -1,3 +1,5 @@
-val typecheck : Types.t_exp -> (Types.ftype, [> Types.typechecking_error]) result
+val typecheck                     : Types.t_exp -> (Types.ftype,  [> Types.typechecking_error]) result
 
-val typecheck_polymorphic : Types.t_exp -> (Types.type_f, [> Types.typechecking_error]) result
+val typecheck_polymorphic         : Types.t_exp -> (Types.type_f, [> Types.typechecking_error]) result
+
+val typecheck_polymorphic_unbound : Types.t_exp -> (Types.type_f, [> Types.typechecking_error]) result

lib/miniFun/Types.ml

@@ -134,6 +134,7 @@ type base_error = [
 type typechecking_error = [
   | base_error
   | `WrongTypeSpecification of string
+  | `RecusrionsNotImplemented of string
 ]
 
 type error = [

lib/miniFun/Types.mli

@@ -29,20 +29,6 @@ module IntegerMap : Map.S with type key = int
 
 val pp_type_f : type_f -> string
 
-(* module VariableTypeMap : Map.S with type key = variable_type *)
-
-(* type substitution = (\* from variable types to politypes *\) *)
-(*   politype VariableTypeMap.t *)
-
-(* type prefix = *)
-(*   | Lambda *)
-(*   | Let *)
-(*   | LetRec *)
-
-(* type typed_prefix = *)
-(*   (\* list of free variables in the context and the associated type *\) *)
-(*   (prefix * politype) VariableMap.t *)
-
 (* -------------------------------------------------------------------------- *)
 
 type ftype = (* type used for specification *)
@@ -106,6 +92,7 @@ type base_error = [
 type typechecking_error = [
   | base_error
   | `WrongTypeSpecification of string
+  | `RecusrionsNotImplemented of string
 ]
 
 type error = [