+module List = ListLabels
+
module A = Tiger_absyn
+module Dag = Tiger_dag
module Env = Tiger_env
module E = Tiger_error
-module Map = Tiger_map
module Pos = Tiger_position
-module Symbol = Tiger_symbol
+module Sym = Tiger_symbol
module Translate = Tiger_translate
module Type = Tiger_env_type
module Value = Tiger_env_value
* Appel's
*)
val transExp : env:Env.t -> A.exp -> expty
- val transVar : env:Env.t -> A.var -> expty
- val transDec : env:Env.t -> A.dec -> Env.t
- val transTy : env:Env.t -> A.ty -> Type.t (* needs only type env *)
+
+ (* transVar does not seem to be needed, as trvar handles all our cases.
+ * Am I wrong?
+ *
+ * val transVar : env:Env.t -> A.var -> expty
+ *
+ *)
end = struct
type expty =
{ exp : Translate.exp
; ty : Type.t
}
- let unimplemented () =
- failwith "unimplemented"
-
- (* TODO: Perhaps a wrapper for env.get that raises semantic error if not found *)
-
- let transExp ~env:_ exp =
- (match exp with
- | A.NilExp ->
- unimplemented ()
- | A.IntExp _ ->
- unimplemented ()
- | A.StringExp {string=_; _} ->
- unimplemented ()
- | A.CallExp {func=_; args=_; pos=_} ->
- unimplemented ()
- | A.OpExp {left=_; oper=_; right=_; pos=_} ->
- unimplemented ()
- | A.RecordExp {fields=_; typ=_; pos=_} ->
- unimplemented ()
- | A.SeqExp _ ->
- unimplemented ()
- | A.AssignExp {var=_; exp=_; _} ->
- unimplemented ()
- | A.IfExp {test=_; then'=_; else'=_; _} ->
- unimplemented ()
- | A.WhileExp {test=_; body=_; _} ->
- unimplemented ()
- | A.ForExp {var=_; lo=_; hi=_; body=_; _} ->
- unimplemented ()
- | A.BreakExp _ ->
- unimplemented ()
- | A.LetExp {decs=_; body=_; _} ->
- unimplemented ()
- | A.ArrayExp {typ=_; size=_; init=_; _} ->
- unimplemented ()
- | A.VarExp _ ->
- unimplemented ()
- )
+ let rec actual_ty ty ~pos =
+ match ty with
+ | Type.Name (name, ty_opt_ref) ->
+ (match !ty_opt_ref with
+ | None ->
+ E.raise (E.Unknown_type {ty_id=name; pos})
+ | Some ty ->
+ actual_ty ty ~pos
+ )
+ | Type.Unit
+ | Type.Nil
+ | Type.Int
+ | Type.String
+ | Type.Record _
+ | Type.Array _ ->
+ ty
+
+ let return ty = {exp = (); ty}
+ let return_unit = return Type.Unit
+ let return_nil = return Type.Nil
+ let return_int = return Type.Int
+ let return_string = return Type.String
+
+ let env_get_typ ~sym ~env ~pos : Type.t =
+ match Env.get_typ env sym with
+ | Some ty -> ty
+ | None -> E.raise (E.Unknown_type {ty_id=sym; pos})
+
+ let env_get_typ_actual ~sym ~env ~pos : Type.t =
+ actual_ty (env_get_typ ~sym ~env ~pos) ~pos
- let transVar ~env:_ var =
- (match var with
- | A.SimpleVar {symbol=_; _} ->
- unimplemented ()
- | A.FieldVar {var=_; symbol=_; _} ->
- unimplemented ()
- | A.SubscriptVar {var=_; exp=_; _} ->
- unimplemented ()
+ let env_get_val ~sym ~env ~pos : Value.t =
+ match Env.get_val env sym with
+ | Some ty -> ty
+ | None -> E.raise (E.Unknown_id {id=sym; pos})
+
+ let check_same {exp=_; ty=ty_left} {exp=_; ty=ty_right} ~pos : unit =
+ if Type.is_equal ty_left ty_right then
+ ()
+ else
+ E.raise (E.Wrong_type {expected=ty_left; given=ty_right; pos})
+
+ let check_int expty ~pos : unit =
+ check_same return_int expty ~pos
+
+ let paths_of_typedecs typedecs : (Sym.t * Sym.t * Pos.t) list list =
+ let (path, paths) =
+ List.fold_left typedecs ~init:([], []) ~f:(
+ fun (path, paths) (A.TypeDec {name=child; ty; pos}) ->
+ match ty with
+ | A.NameTy {symbol=parent; _} ->
+ (((parent, child, pos) :: path), paths)
+ | A.RecordTy _
+ | A.ArrayTy _ ->
+ ([], path :: paths)
+ )
+ in
+ List.map (path :: paths) ~f:List.rev
+
+ let check_cycles (typedecs : A.typedec list) : unit =
+ let non_empty_paths =
+ List.filter
+ (paths_of_typedecs typedecs)
+ ~f:(function [] -> false | _ -> true)
+ in
+ List.iter non_empty_paths ~f:(
+ fun path ->
+ match Dag.of_list (List.map path ~f:(fun (p, c, _) -> (p, c))) with
+ | Ok _ ->
+ ()
+ | Error `Cycle ->
+ let (_, from_id, from_pos) = List.hd path in
+ let (_, to_id, to_pos) = List.hd (List.rev path) in
+ E.raise (E.Cycle_in_type_decs {from_id; from_pos; to_id; to_pos})
)
- let transDec ~env:_ dec =
+ let rec transExp ~env exp =
+ let rec trexp exp =
+ (match exp with
+ | A.NilExp ->
+ return_nil
+ | A.IntExp _ ->
+ return_int
+ | A.StringExp {string=_; _} ->
+ return_string
+ | A.CallExp {func; args; pos} ->
+ (match env_get_val ~sym:func ~env ~pos with
+ | Value.Fun {formals; result} ->
+ let expected = List.length formals in
+ let given = List.length args in
+ if given = expected then
+ begin
+ List.iter2 formals args ~f:(fun ty_expected exp_given ->
+ check_same
+ (return (actual_ty ~pos ty_expected))
+ (trexp exp_given)
+ ~pos;
+ );
+ return (actual_ty ~pos result)
+ end
+ else
+ E.raise (E.Wrong_number_of_args {func; expected; given; pos})
+ | Value.Var _ ->
+ E.raise (E.Id_not_a_function {id=func; pos})
+ )
+ | A.OpExp {oper; left; right; pos} ->
+ trop oper ~left ~right ~pos
+ | A.RecordExp {fields=field_exps; typ; pos} ->
+ let ty = env_get_typ_actual ~sym:typ ~env ~pos in
+ Type.if_record
+ ty
+ ~f:(fun field_tys ->
+ List.iter field_exps ~f:(fun (field, exp, pos) ->
+ (match List.assoc_opt field field_tys with
+ | Some field_ty ->
+ check_same (return (actual_ty ~pos field_ty)) (trexp exp) ~pos
+ | None ->
+ E.raise
+ (E.No_such_field_in_record {field; record=ty; pos})
+ )
+ )
+ )
+ ~otherwise:(fun () ->
+ E.raise (E.Wrong_type_used_as_record {ty_id=typ; ty; pos})
+ );
+ return (actual_ty ~pos ty)
+ | A.SeqExp [] ->
+ return_unit
+ | A.SeqExp exps ->
+ let last xs =
+ xs
+ |> List.rev (* Yes, redundant, but clean-looking ;-P *)
+ |> List.hd (* Empty is matched in above SeqExp match case *)
+ in
+ exps
+ |> List.map ~f:(fun (exp, _) -> trexp exp)
+ |> last
+ | A.AssignExp {var; exp; pos} ->
+ check_same (trvar var) (trexp exp) ~pos;
+ (* TODO: Add var->exp to val env? *)
+ return_unit
+ | A.IfExp {test; then'; else'; pos} ->
+ (* test : must be int, because we have no bool *)
+ (* then : must equal else *)
+ (* else : must equal then or be None *)
+ check_int (trexp test) ~pos;
+ (match (trexp then', else') with
+ | expty_then, None ->
+ expty_then
+ | expty_then, Some else' ->
+ let expty_else = trexp else' in
+ check_same expty_then expty_else ~pos;
+ expty_then
+ )
+ | A.WhileExp {test; body; pos} ->
+ (* test : must be int, because we have no bool *)
+ check_int (trexp test) ~pos;
+ ignore (trexp body); (* Only care if a type-error is raised *)
+ return_unit
+ | A.ForExp {var; lo; hi; body; pos; escape=_} ->
+ check_int (trexp lo) ~pos;
+ check_int (trexp hi) ~pos;
+ (* Only care if a type-error is raised *)
+ let env = Env.set_val env var (Value.Var {ty = Type.Int}) in
+ ignore (transExp ~env body);
+ return_unit
+ | A.BreakExp _ ->
+ return_unit
+ | A.LetExp {decs; body; pos=_} ->
+ (* (1) decs augment env *)
+ (* (2) body checked against the new env *)
+ let env =
+ List.fold_left decs ~init:env ~f:(fun env dec -> transDec dec ~env)
+ in
+ transExp body ~env
+ | A.ArrayExp {typ; size; init; pos} ->
+ check_int (trexp size) ~pos;
+ let ty = env_get_typ_actual ~sym:typ ~env ~pos in
+ Type.if_array
+ ty
+ ~f:(fun ty_elements ->
+ check_same (return (actual_ty ~pos ty_elements)) (trexp init) ~pos
+ )
+ ~otherwise:(fun () ->
+ E.raise (E.Wrong_type_used_as_array {ty_id=typ; ty; pos})
+ );
+ return (actual_ty ~pos ty)
+ | A.VarExp var ->
+ trvar var
+ )
+ and trvar =
+ (function
+ | A.SimpleVar {symbol=sym; pos} ->
+ (match env_get_val ~sym ~env ~pos with
+ | Value.Fun _ -> E.raise (E.Id_is_a_function {id=sym; pos})
+ | Value.Var {ty} -> return (actual_ty ~pos ty)
+ )
+ | A.FieldVar {var; symbol; pos} ->
+ let {exp=_; ty} = trvar var in
+ Type.if_record
+ ty
+ ~f:(fun fields ->
+ (match List.assoc_opt symbol fields with
+ | None ->
+ E.raise
+ (E.No_such_field_in_record {field=symbol; record=ty; pos})
+ | Some ty ->
+ return (actual_ty ~pos ty)
+ )
+ )
+ ~otherwise:(fun () -> E.raise (E.Exp_not_a_record {ty; pos}))
+ | A.SubscriptVar {var; exp; pos} ->
+ let {exp=_; ty} = trvar var in
+ check_int (trexp exp) ~pos;
+ Type.if_array
+ ty
+ ~f:(fun ty_elements -> return (actual_ty ~pos ty_elements))
+ ~otherwise:(fun () -> E.raise (E.Exp_not_an_array {ty; pos}))
+ )
+ and trop oper ~left ~right ~pos =
+ (* TODO: Refactor trop - all opers return bool/int *)
+ let expty_left = trexp left in
+ let expty_right = trexp right in
+ check_same expty_left expty_right ~pos;
+ let {exp=_; ty} = expty_left in
+ let module T = Type in
+ (match oper with
+ (* Arithmetic: int *)
+ | A.PlusOp
+ | A.MinusOp
+ | A.TimesOp
+ | A.DivideOp ->
+ check_int expty_left ~pos;
+ return_int
+ (* Equality: int, string, array, record *)
+ | A.EqOp
+ | A.NeqOp ->
+ if (T.is_int ty)
+ || (T.is_string ty)
+ || (T.is_array ty)
+ || (T.is_record ty)
+ then
+ return_int (* Because we have no bool type *)
+ else
+ E.raise (E.Invalid_operand_type
+ { oper
+ ; valid = ["int"; "string"; "array"; "record"]
+ ; given = ty
+ ; pos
+ })
+ (* Order: int, string *)
+ | A.LtOp
+ | A.LeOp
+ | A.GtOp
+ | A.GeOp ->
+ if (T.is_int ty)
+ || (T.is_string ty)
+ then
+ return_int (* Because we have no bool type *)
+ else
+ E.raise (E.Invalid_operand_type
+ { oper
+ ; valid = ["int"; "string"]
+ ; given = ty
+ ; pos
+ })
+ )
+ in
+ trexp exp
+ and transDec ~(env : Env.t) (dec : A.dec) : Env.t =
(match dec with
- | A.VarDec {name=_; typ=_; init=_; pos=_; escape=_} ->
- unimplemented ()
- | A.TypeDecs _ ->
- unimplemented ()
- | A.FunDecs _ ->
- unimplemented ()
+ | A.VarDec {name; typ=typ_opt; init; pos=pos_outter; escape=_} ->
+ let ty =
+ (match (typ_opt, transExp ~env init) with
+ | None, {ty; exp=()} ->
+ ty
+ | Some (sym, pos_inner), expty_init ->
+ let ty = env_get_typ_actual ~sym ~env ~pos:pos_inner in
+ check_same (return ty) expty_init ~pos:pos_outter;
+ ty
+ )
+ in
+ Env.set_val env name (Value.Var {ty})
+ | A.TypeDecs typedecs ->
+ check_cycles typedecs;
+ let env =
+ List.fold_left typedecs ~init:env ~f:(
+ fun env (A.TypeDec {name; ty=_; pos=_}) ->
+ Env.set_typ env name (Type.Name (name, ref None))
+ )
+ in
+ List.iter typedecs ~f:(fun (A.TypeDec {name; ty=ty_exp; pos}) ->
+ let ty = transTy ~env ty_exp in
+ (match env_get_typ ~sym:name ~env ~pos with
+ | Type.Name (_, ty_opt_ref) ->
+ ty_opt_ref := Some ty
+ | Type.Unit
+ | Type.Nil
+ | Type.Int
+ | Type.String
+ | Type.Record _
+ | Type.Array _ ->
+ ()
+ )
+ );
+ env
+ | A.FunDecs fundecs ->
+ let env_with_fun_heads_only =
+ List.fold_left fundecs ~init:env ~f:(
+ fun env (A.FunDec {name; params; result; body=_; pos=_}) ->
+ let formals =
+ List.map params ~f:(
+ fun (A.Field {name=_; typ; pos; escape=_}) ->
+ env_get_typ_actual ~env ~sym:typ ~pos
+ )
+ in
+ let result =
+ match result with
+ | Some (s, p) -> env_get_typ_actual ~sym:s ~env ~pos:p
+ | None -> Type.Unit
+ in
+ Env.set_val env name (Value.Fun {formals; result})
+ )
+ in
+ List.iter fundecs ~f:(
+ fun (A.FunDec {name=_; params; result=_; body; pos=_}) ->
+ let env_with_fun_heads_and_local_vars =
+ List.fold_left params ~init:env_with_fun_heads_only ~f:(
+ fun env (A.Field {name=var_name; escape=_; typ; pos}) ->
+ let var_ty = env_get_typ_actual ~env ~sym:typ ~pos in
+ Env.set_val env var_name (Value.Var {ty = var_ty})
+ )
+ in
+ (* we only care if an exception is raised *)
+ ignore (transExp ~env:env_with_fun_heads_and_local_vars body);
+ );
+ env_with_fun_heads_only
)
-
- let transTy ~env:_ typ =
- (match typ with
- | A.NameTy {symbol = _; pos = _} ->
- unimplemented ()
- | A.RecordTy _ ->
- unimplemented ()
- | A.ArrayTy {symbol = _; pos = _} ->
- unimplemented ()
+ and transTy ~(env : Env.t) (ty_exp : A.ty) : Type.t =
+ (match ty_exp with
+ | A.NameTy {symbol=sym; pos} ->
+ env_get_typ ~sym ~env ~pos
+ | A.RecordTy fields ->
+ let fields =
+ List.map fields ~f:(fun (A.Field {name; escape=_; typ; pos}) ->
+ let ty = env_get_typ ~sym:typ ~env ~pos in
+ (name, ty)
+ )
+ in
+ Type.new_record fields
+ | A.ArrayTy {symbol=sym; pos} ->
+ let element_ty = env_get_typ ~sym ~env ~pos in
+ Type.new_array element_ty
)
end
+open Semant
+
let transProg absyn =
- let open Semant in
let {exp = _; ty = _} = transExp absyn ~env:Env.base in
()
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