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open Stdlib_extra
open Ast
type env = {
def_tbl: Predef.table;
imports: Imports.t;
}
let add_name accu = function
Name (_, (_, k, _), _) -> k :: accu
| _ -> accu
let get_kind = function
Sum _ -> `Sum
| Record _ -> `Record
| _ -> `Other
let check_inheritance env (t0 : type_expr) =
let not_a kind _ =
let msg =
sprintf "Cannot inherit from non-%s type"
(match kind with
`Sum -> "variant"
| `Record -> "record"
| _ -> assert false)
in
error_at (loc_of_type_expr t0) msg
in
let rec check kind inherited (t : type_expr) =
match t with
Sum (_, vl, _) when kind = `Sum ->
List.iter (fun (x : variant) ->
match x with
| Inherit (_, t) -> check kind inherited t
| Variant _ -> ()
) vl
| Record (_, fl, _) when kind = `Record ->
List.iter (fun (x : field) ->
match x with
| Inherit (_, t) -> check kind inherited t
| Field _ -> ()
) fl
| Sum _
| Record _
| Tuple _
| List _
| Option _
| Nullable _
| Shared _
| Wrap _ as x -> not_a kind x
| Name (_, (loc, name, _), _) ->
if List.mem name inherited then
error_at (loc_of_type_expr t0) "Cyclic inheritance"
else
let (_arity, opt_def) =
match Imports.resolve env.imports loc name with
| Some _, _base_name ->
error_at loc ("We cannot inherit from an external type: "
^ Print.tn name)
| None, base_name ->
try Hashtbl.find env.def_tbl name
with Not_found ->
error_at loc ("Undefined type " ^ base_name)
in
(match opt_def with
None -> ()
| Some x -> check kind (x.name :: inherited) x.value
)
| Tvar _ ->
error_at (loc_of_type_expr t0) "Cannot inherit from a type variable"
in
check (get_kind t0) (add_name [] t0) t0
let check_type_expr env tvars (t : type_expr) =
let rec check : type_expr -> unit = function
Sum (_, vl, _) as x ->
List.iter (check_variant (Hashtbl.create 10)) vl;
check_inheritance env x
| Record (_, fl, _) as x ->
List.iter (check_field (Hashtbl.create 10)) fl;
check_inheritance env x
| Tuple (_, tl, _) -> List.iter (fun (_, x, _) -> check x) tl
| List (_, t, _) -> check t
| Option (_, t, _) -> check t
| Nullable (_, t, _) -> check t
| Shared (loc, t, _) ->
if Ast.is_parametrized t then
error_at loc "Shared type cannot be polymorphic";
check t
| Wrap (_, t, _) -> check t
| Name (_, (loc, name, tal), _) ->
assert (name <> TN ["list"] && name <> TN ["option"]
&& name <> TN ["nullable"] && name <> TN ["shared"]
&& name <> TN ["wrap"]);
(match Imports.resolve env.imports loc name with
| Some _, _base_name ->
()
| None, base_name ->
let (arity, _opt_def) =
try Hashtbl.find env.def_tbl name
with Not_found ->
error_at loc ("Undefined type " ^ base_name)
in
let n = List.length tal in
if arity <> n then
error_at loc (sprintf
"Type %s was defined to take %i parameters, \
but %i argument%s."
(Print.tn name)
arity n
(if n > 1 then "s are given"
else " is given")
);
List.iter check tal
)
| Tvar (loc, s) ->
if not (List.mem s tvars) then
error_at loc (sprintf "Unbound type variable '%s" s)
and check_variant accu = function
Variant (loc, (k, _), opt_t) ->
if Hashtbl.mem accu k then
error_at loc
(sprintf
"Multiple definitions of the same variant constructor %s" k);
Hashtbl.add accu k ();
(match opt_t with
None -> ()
| Some t -> check t)
| Inherit (_, t) ->
check t
and check_field accu = function
| Field (loc, (k, _, _), t) ->
if Hashtbl.mem accu k then
error_at loc
(sprintf "Multiple definitions of the same field %s" k);
Hashtbl.add accu k ();
check t
| Inherit (_, t) ->
check t
in
check t
let check (x : Ast.module_) =
let env = {
def_tbl = Predef.make_table x.type_defs;
imports = Imports.load x.imports;
} in
List.iter (fun (x : type_def) ->
check_type_expr env x.param x.value
) x.type_defs