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open Printf
open Atd_ast
let add_name accu = function
`Name (_, (loc, k, tal), _) -> k :: accu
| _ -> accu
let get_kind = function
`Sum _ -> `Sum
| `Record _ -> `Record
| _ -> `Other
let check_inheritance tbl (t0 : type_expr) =
let not_a kind x =
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 (
function
`Inherit (_, t) -> check kind inherited t
| `Variant _ -> ()
) vl
| `Record (_, fl, _) when kind = `Record ->
List.iter (
function
`Inherit (_, t) -> check kind inherited t
| `Field _ -> ()
) fl
| `Sum _
| `Record _
| `Tuple _
| `List _
| `Option _
| `Nullable _
| `Shared _
| `Wrap _ as x -> not_a kind x
| `Name (_, (loc, k, tal), _) ->
if List.mem k inherited then
error_at (loc_of_type_expr t0) "Cyclic inheritance"
else
let (arity, opt_def) =
try Hashtbl.find tbl k
with Not_found -> error_at loc ("Undefined type " ^ k)
in
(match opt_def with
None -> ()
| Some (_, _, t) -> check kind (k :: inherited) t
)
| `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 tbl 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 tbl x
| `Record (_, fl, _) as x ->
List.iter (check_field (Hashtbl.create 10)) fl;
check_inheritance tbl 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 Atd_ast.is_parametrized t then
error_at loc "Shared type cannot be polymorphic";
check t
| `Wrap (_, t, _) -> check t
| `Name (_, (loc, k, tal), _) ->
assert (k <> "list" && k <> "option"
&& k <> "nullable" && k <> "shared" && k <> "wrap");
let (arity, opt_def) =
try Hashtbl.find tbl k
with Not_found -> error_at loc ("Undefined type " ^ k)
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."
k 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, fk, _), 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 (l : Atd_ast.module_body) =
let predef = Atd_predef.make_table () in
let tbl = Hashtbl.copy predef in
List.iter (
function `Type ((loc, (k, pl, a), t) as x) ->
if Hashtbl.mem tbl k then
if Hashtbl.mem predef k then
error_at loc
(sprintf "%s is a predefined type, it cannot be redefined." k)
else
error_at loc
(sprintf "Type %s is defined for the second time." k)
else
Hashtbl.add tbl k (List.length pl, Some x)
) l;
List.iter (
function `Type (loc, (k, tvars, a), t) ->
check_type_expr tbl tvars t
) l;