Paris7/unification-pfa
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this doesnt work

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Mylloon 2024-04-11 11:48:47 +02:00
parent 16aee95bb3
commit ab270e2246
Signed by: Anri
GPG key ID: A82D63DFF8D1317F
1 changed files with 31 additions and 20 deletions
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51
lib/inference.ml
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@ -1,32 +1,43 @@
(** Infer the type of a given term and, if exists, returns the type of the term *) (** Infer the type of a given term and, if exists, returns the type of the term *)
let rec typeof = function let rec typeof = function
| Term.Var _ -> None | Term.Var id ->
(match Unification.unify (Type.Var id) Type.Int with
| Some _ -> Some Type.Int
| None -> Some (Type.Var id))
| Term.IntConst _ -> Some Type.Int | Term.IntConst _ -> Some Type.Int
| Term.Binop (t1, _, t2) -> | Term.Binop (t1, _, t2) ->
(* Both operands must have type Int *)
(match typeof t1, typeof t2 with (match typeof t1, typeof t2 with
| ty1, ty2 when ty1 = ty2 -> Some Type.Int | Some ty1, Some ty2 ->
| _ -> None) (match Unification.unify ty1 Type.Int, Unification.unify ty2 Type.Int with
| Some _, Some _ -> Some Type.Int
| _ -> None)
| _, _ -> None)
| Term.Pair (t1, t2) -> | Term.Pair (t1, t2) ->
(* Pair give Products *)
(match typeof t1, typeof t2 with (match typeof t1, typeof t2 with
| Some ty1, Some ty2 -> Some (Type.Product (ty1, ty2)) | Some ty1, Some ty2 -> Some (Type.Product (ty1, ty2))
| _ -> None)
| Term.Proj (proj, t) ->
(* Projections returns type of product based on the projection type *)
(match proj, typeof t with
| Term.First, Some (Type.Product (ty, _)) | Term.Second, Some (Type.Product (_, ty))
-> Some ty
| _, _ -> None) | _, _ -> None)
| Term.Fun (id, t) -> | Term.Proj (proj, t) ->
(* Check if the term is a pair *)
(match typeof t with (match typeof t with
| Some body_type -> Some (Type.Arrow (Type.Int, body_type)) | Some (Type.Product (ty1, ty2)) ->
| None -> Some (Type.Var id)) (match proj with
| Term.App (t1, t2) -> | Term.First -> Some ty1
(match typeof t1, typeof t2 with | Term.Second -> Some ty2)
| Some (Type.Arrow (ty_arg, ty_res)), Some ty_arg' ->
(* Unification for application *)
(match Unification.unify ty_arg ty_arg' with
| Some subst -> Some (TypeSubstitution.apply subst ty_res)
| None -> None)
| _ -> None) | _ -> None)
| Term.Fun (id, body) ->
(match typeof body with
| Some ty_body ->
(match typeof (Term.Var id) with
| Some tt -> Some (Type.Arrow (tt, ty_body))
| None -> Some (Type.Arrow (Type.Var id, ty_body)))
| _ -> None)
| Term.App (t1, t2) ->
(* Check if the function type matches the arguments *)
(match typeof t1, typeof t2 with
| Some (Type.Arrow (ty_param, ty_fn)), Some ty_args ->
(match Unification.unify ty_param ty_args with
| Some _ -> Some ty_fn
| None -> None)
| _, _ -> None)
;; ;;