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
23 (* transVar does not seem to be needed, as trvar handles all our cases.
26 * val transVar : env:Env.t -> A.var -> expty
35 let return ty = {exp = (); ty}
36 let return_unit = return Type.Unit
37 let return_nil = return Type.Nil
38 let return_int = return Type.Int
39 let return_string = return Type.String
41 let env_get_typ ~sym ~env ~pos : Type.t =
42 match Env.get_typ env sym with
44 | None -> E.raise (E.Unknown_type {ty_id=sym; pos})
46 let env_get_val ~sym ~env ~pos : Value.t =
47 match Env.get_val env sym with
49 | None -> E.raise (E.Unknown_id {id=sym; pos})
51 let check_same {exp=_; ty=ty_left} {exp=_; ty=ty_right} ~pos : unit =
52 if Type.is_equal ty_left ty_right then
55 E.raise (E.Wrong_type {expected=ty_left; given=ty_right; pos})
57 let check_int expty ~pos : unit =
58 check_same {exp=(); ty=Type.Int} expty ~pos
61 (* TODO: mutual recursion *)
63 let rec transExp ~env exp =
70 | A.StringExp {string=_; _} ->
72 | A.CallExp {func; args; pos} ->
73 (match env_get_val ~sym:func ~env ~pos with
74 | Value.Fun {formals; result} ->
75 List.iter2 formals args ~f:(fun ty_expected exp_given ->
76 check_same {exp=(); ty = ty_expected} (trexp exp_given) ~pos;
80 E.raise (E.Id_not_a_function {id=func; pos})
82 | A.OpExp {oper; left; right; pos} ->
83 trop oper ~left ~right ~pos
84 | A.RecordExp {fields=field_exps; typ; pos} ->
85 let ty = env_get_typ ~sym:typ ~env ~pos in
89 List.iter field_exps ~f:(fun (field, exp, pos) ->
90 (match List.assoc_opt field field_tys with
92 check_same {exp=(); ty=field_ty} (trexp exp) ~pos
95 (E.No_such_field_in_record {field; record=ty; pos})
100 E.raise (E.Wrong_type_used_as_record {ty_id=typ; ty; pos})
108 |> List.rev (* Yes, redundant, but clean-looking ;-P *)
109 |> List.hd (* Empty is matched in above SeqExp match case *)
112 |> List.map ~f:(fun (exp, _) -> let {ty; _} = trexp exp in ty)
115 | A.AssignExp {var; exp; pos} ->
116 check_same (trvar var) (trexp exp) ~pos;
117 (* TODO: Add var->exp to val env? *)
119 | A.IfExp {test; then'; else'; pos} ->
120 (* test : must be int, because we have no bool *)
121 (* then : must equal else *)
122 (* else : must equal then or be None *)
123 check_int (trexp test) ~pos;
124 (match (trexp then', else') with
125 | expty_then, None ->
127 | expty_then, Some else' ->
128 let expty_else = trexp else' in
129 check_same expty_then expty_else ~pos;
132 | A.WhileExp {test; body; pos} ->
133 (* test : must be int, because we have no bool *)
134 check_int (trexp test) ~pos;
135 ignore (trexp body); (* Only care if a type-error is raised *)
137 | A.ForExp {var; lo; hi; body; pos; escape=_} ->
138 check_int (trexp lo) ~pos;
139 check_int (trexp hi) ~pos;
140 (* Only care if a type-error is raised *)
141 let env = Env.set_val env var (Value.Var {ty = Type.Int}) in
142 ignore (transExp ~env body);
146 | A.LetExp {decs; body; pos=_} ->
147 (* (1) decs augment env *)
148 (* (2) body checked against the new env *)
150 List.fold_left decs ~init:env ~f:(fun env dec -> transDec dec ~env)
153 | A.ArrayExp {typ; size; init; pos} ->
154 check_int (trexp size) ~pos;
155 let ty = env_get_typ ~sym:typ ~env ~pos in
158 ~f:(fun ty_elements ->
159 check_same {exp=(); ty=ty_elements} (trexp init) ~pos
161 ~otherwise:(fun () ->
162 E.raise (E.Wrong_type_used_as_array {ty_id=typ; ty; pos})
170 | A.SimpleVar {symbol=sym; pos} ->
171 (match env_get_val ~sym ~env ~pos with
172 | Value.Fun _ -> E.raise (E.Id_is_a_function {id=sym; pos})
173 | Value.Var {ty} -> return ty
175 | A.FieldVar {var; symbol; pos} ->
176 let {exp=_; ty} = trvar var in
180 (match List.assoc_opt symbol fields with
183 (E.No_such_field_in_record {field=symbol; record=ty; pos})
188 ~otherwise:(fun () -> E.raise (E.Exp_not_a_record {ty; pos}))
189 | A.SubscriptVar {var; exp; pos} ->
190 let {exp=_; ty} = trvar var in
191 check_int (trexp exp) ~pos;
194 ~f:(fun ty_elements -> return ty_elements)
195 ~otherwise:(fun () -> E.raise (E.Exp_not_an_array {ty; pos}))
197 and trop oper ~left ~right ~pos =
198 let expty_left = trexp left in
199 let expty_right = trexp right in
200 check_same expty_left expty_right ~pos;
201 let {exp=_; ty} = expty_left in
202 let module T = Type in
204 (* Arithmetic: int *)
209 check_int expty_left ~pos;
211 (* Equality: int, string, array, record *)
221 E.raise (E.Invalid_operand_type
223 ; valid = ["int"; "string"; "array"; "record"]
227 (* Order: int, string *)
237 E.raise (E.Invalid_operand_type
239 ; valid = ["int"; "string"]
246 and transDec ~(env : Env.t) (dec : A.dec) : Env.t =
248 | A.VarDec {name; typ=typ_opt; init; pos=pos_outter; escape=_} ->
250 (match (typ_opt, transExp ~env init) with
251 | None, {ty; exp=()} ->
253 | Some (sym, pos_inner), expty_init ->
254 let ty = env_get_typ ~sym ~env ~pos:pos_inner in
255 check_same {exp=(); ty} expty_init ~pos:pos_outter;
259 Env.set_val env name (Value.Var {ty})
260 | A.TypeDecs typedecs ->
261 List.fold_left typedecs ~init:env ~f:(
262 fun env (A.TypeDec {name; ty; pos=_}) ->
263 let ty = transTy ~env ty in
264 Env.set_typ env name ty
266 | A.FunDecs fundecs ->
267 List.fold_left fundecs ~init:env ~f:(
268 fun env (A.FunDec {name; params; result; body; pos=_}) ->
269 let (env_for_body, formals_in_reverse_order) =
270 List.fold_left params ~init:(env, []) ~f:(
271 fun (env, formals) (A.Field {name; escape=_; typ; pos}) ->
272 let ty = env_get_typ ~env ~sym:typ ~pos in
273 let env = Env.set_val env name (Value.Var {ty}) in
277 (* ignore because we only care if an exception is raised *)
278 ignore (transExp ~env:env_for_body body);
279 let formals = List.rev formals_in_reverse_order in
285 env_get_typ ~sym ~env ~pos
287 Env.set_val env name (Value.Fun {formals; result})
290 and transTy ~(env : Env.t) (typ : A.ty) : Type.t =
292 | A.NameTy {symbol=sym; pos} ->
293 env_get_typ ~sym ~env ~pos
294 | A.RecordTy fields ->
296 List.map fields ~f:(fun (A.Field {name; escape=_; typ; pos}) ->
297 let ty = env_get_typ ~sym:typ ~env ~pos in
301 Type.new_record fields
302 | A.ArrayTy {symbol=sym; pos} ->
303 let element_ty = env_get_typ ~sym ~env ~pos in
304 Type.new_array element_ty
310 let transProg absyn =
311 let {exp = _; ty = _} = transExp absyn ~env:Env.base in