1 module List = ListLabels
6 module Translate = Tiger_translate
7 module Type = Tiger_env_type
8 module Value = Tiger_env_value
10 (* The only reason for having this seemingly-superfluous inner module is to
11 * have this nice signature as a summary of what each function does. *)
18 (* Violating normal naming convention just to make it easier to follow
21 val transExp : env:Env.t -> A.exp -> expty
22 val transVar : env:Env.t -> A.var -> expty
23 val transDec : env:Env.t -> A.dec -> Env.t
24 val transTy : env:Env.t -> A.ty -> Type.t (* needs only type env *)
31 let unimplemented () =
32 failwith "unimplemented"
34 let return ty = {exp = (); ty}
35 let return_unit = return Type.Unit
36 let return_nil = return Type.Nil
37 let return_int = return Type.Int
38 let return_string = return Type.String
40 let env_get_typ ~sym ~env ~pos : Type.t =
41 match Env.get_typ env sym with
43 | None -> E.raise (E.Unknown_type {ty_id=sym; pos})
45 let env_get_val ~sym ~env ~pos : Value.t =
46 match Env.get_val env sym with
48 | None -> E.raise (E.Unknown_id {id=sym; pos})
50 let check_same {exp=_; ty=ty_left} {exp=_; ty=ty_right} ~pos : unit =
51 if Type.is_equal ty_left ty_right then
54 E.raise (E.Wrong_type {expected=ty_left; given=ty_right; pos})
56 let check_int expty ~pos : unit =
57 check_same {exp=(); ty=Type.Int} expty ~pos
60 (* TODO: mutual recursion *)
62 let rec transExp ~env exp =
69 | A.StringExp {string=_; _} ->
71 | A.CallExp {func; args; pos} ->
72 (match env_get_val ~sym:func ~env ~pos with
73 | Value.Fun {formals; result} ->
74 List.iter2 formals args ~f:(fun ty_expected exp_given ->
75 check_same {exp=(); ty = ty_expected} (trexp exp_given) ~pos;
79 E.raise (E.Id_not_a_function {id=func; pos})
81 | A.OpExp {oper; left; right; pos} ->
82 trop oper ~left ~right ~pos
83 | A.RecordExp {fields=field_exps; typ; pos} ->
84 let ty = env_get_typ ~sym:typ ~env ~pos in
88 List.iter field_exps ~f:(fun (field, exp, pos) ->
89 (match List.assoc_opt field field_tys with
91 check_same {exp=(); ty=field_ty} (trexp exp) ~pos
94 (E.No_such_field_in_record {field; record=ty; pos})
99 E.raise (E.Wrong_type_used_as_record {ty_id=typ; ty; pos})
103 (* Ignoring value because we only care if a type-checking exception
104 * is raised in one of trexp calls: *)
105 List.iter exps ~f:(fun (exp, _) -> ignore (trexp exp));
107 | A.AssignExp {var; exp; pos} ->
108 check_same (trvar var) (trexp exp) ~pos;
109 (* TODO: Add var->exp to val env? *)
111 | A.IfExp {test; then'; else'; pos} ->
112 (* test : must be int, because we have no bool *)
113 (* then : must equal else *)
114 (* else : must equal then or be None *)
115 check_int (trexp test) ~pos;
116 (match (trexp then', else') with
117 | expty_then, None ->
119 | expty_then, Some else' ->
120 let expty_else = trexp else' in
121 check_same expty_then expty_else ~pos;
124 | A.WhileExp {test; body; pos} ->
125 (* test : must be int, because we have no bool *)
126 check_int (trexp test) ~pos;
127 ignore (trexp body); (* Only care if a type-error is raised *)
129 | A.ForExp {var; lo; hi; body; pos; escape=_} ->
130 check_int (trexp lo) ~pos;
131 check_int (trexp hi) ~pos;
132 (* Only care if a type-error is raised *)
133 ignore (transExp ~env:(Env.set_typ env var Type.Int) body);
137 | A.LetExp {decs; body; pos=_} ->
138 (* (1) decs augment env *)
139 (* (2) body checked against the new env *)
141 List.fold_left decs ~init:env ~f:(fun env dec -> transDec dec ~env)
144 | A.ArrayExp {typ; size; init; pos} ->
145 check_int (trexp size) ~pos;
146 let ty = env_get_typ ~sym:typ ~env ~pos in
149 ~f:(fun ty_elements ->
150 check_same {exp=(); ty=ty_elements} (trexp init) ~pos
152 ~otherwise:(fun () ->
153 E.raise (E.Wrong_type_used_as_array {ty_id=typ; ty; pos})
161 | A.SimpleVar {symbol=sym; pos} ->
162 (match env_get_val ~sym ~env ~pos with
163 | Value.Fun _ -> E.raise (E.Id_is_a_function {id=sym; pos})
164 | Value.Var {ty} -> return ty
166 | A.FieldVar {var; symbol; pos} ->
167 let {exp=_; ty} = trvar var in
171 (match List.assoc_opt symbol fields with
174 (E.No_such_field_in_record {field=symbol; record=ty; pos})
179 ~otherwise:(fun () -> E.raise (E.Exp_not_a_record {ty; pos}))
180 | A.SubscriptVar {var; exp; pos} ->
181 let {exp=_; ty} = trvar var in
182 check_int (trexp exp) ~pos;
185 ~f:(fun ty_elements -> return ty_elements)
186 ~otherwise:(fun () -> E.raise (E.Exp_not_an_array {ty; pos}))
188 and trop oper ~left ~right ~pos =
189 let expty_left = trexp left in
190 let expty_right = trexp right in
191 check_same expty_left expty_right ~pos;
192 let {exp=_; ty} = expty_left in
193 let module T = Type in
195 (* Arithmetic: int *)
200 check_int expty_left ~pos;
202 (* Equality: int, string, array, record *)
212 E.raise (E.Invalid_operand_type
214 ; valid = ["int"; "string"; "array"; "record"]
218 (* Order: int, string *)
228 E.raise (E.Invalid_operand_type
230 ; valid = ["int"; "string"]
237 and transDec ~env dec =
239 | A.VarDec {name; typ=typ_opt; init; pos=pos_outter; escape=_} ->
241 (match (typ_opt, transExp ~env init) with
242 | None, {ty; exp=()} ->
244 | Some (sym, pos_inner), expty_init ->
245 let ty = env_get_typ ~sym ~env ~pos:pos_inner in
246 check_same {exp=(); ty} expty_init ~pos:pos_outter;
250 Env.set_val env name (Value.Var {ty})
251 | A.TypeDecs typedecs ->
252 List.fold_left typedecs ~init:env ~f:(
253 fun env (A.TypeDec {name; ty; pos=_}) ->
254 let ty = transTy ~env ty in
255 Env.set_typ env name ty
260 and transTy ~env typ =
262 | A.NameTy {symbol=sym; pos} ->
263 env_get_typ ~sym ~env ~pos
264 | A.RecordTy fields ->
266 List.map fields ~f:(fun (A.Field {name; escape=_; typ; pos}) ->
267 let ty = env_get_typ ~sym:typ ~env ~pos in
271 Type.new_record fields
272 | A.ArrayTy {symbol=sym; pos} ->
273 let element_ty = env_get_typ ~sym ~env ~pos in
274 Type.new_array element_ty
277 let transVar ~env:_ var =
279 | A.SimpleVar {symbol=_; _} ->
281 | A.FieldVar {var=_; symbol=_; _} ->
283 | A.SubscriptVar {var=_; exp=_; _} ->
290 let transProg absyn =
291 let {exp = _; ty = _} = transExp absyn ~env:Env.base in