ocaml/typing/datarepr.ml

141 lines
4.9 KiB
OCaml

(***********************************************************************)
(* *)
(* OCaml *)
(* *)
(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
(* *)
(* Copyright 1996 Institut National de Recherche en Informatique et *)
(* en Automatique. All rights reserved. This file is distributed *)
(* under the terms of the Q Public License version 1.0. *)
(* *)
(***********************************************************************)
(* Compute constructor and label descriptions from type declarations,
determining their representation. *)
open Asttypes
open Types
open Btype
(* Simplified version of Ctype.free_vars *)
let free_vars ty =
let ret = ref TypeSet.empty in
let rec loop ty =
let ty = repr ty in
if ty.level >= lowest_level then begin
ty.level <- pivot_level - ty.level;
match ty.desc with
| Tvar _ ->
ret := TypeSet.add ty !ret
| Tvariant row ->
let row = row_repr row in
iter_row loop row;
if not (static_row row) then loop row.row_more
| _ ->
iter_type_expr loop ty
end
in
loop ty;
unmark_type ty;
!ret
let constructor_descrs ty_res cstrs priv =
let num_consts = ref 0 and num_nonconsts = ref 0 and num_normal = ref 0 in
List.iter
(fun (name, args, ret) ->
if args = [] then incr num_consts else incr num_nonconsts;
if ret = None then incr num_normal)
cstrs;
let rec describe_constructors idx_const idx_nonconst = function
[] -> []
| (id, ty_args, ty_res_opt) :: rem ->
let ty_res =
match ty_res_opt with
| Some ty_res' -> ty_res'
| None -> ty_res
in
let (tag, descr_rem) =
match ty_args with
[] -> (Cstr_constant idx_const,
describe_constructors (idx_const+1) idx_nonconst rem)
| _ -> (Cstr_block idx_nonconst,
describe_constructors idx_const (idx_nonconst+1) rem) in
let existentials =
match ty_res_opt with
| None -> []
| Some type_ret ->
let res_vars = free_vars type_ret in
let arg_vars = free_vars (newgenty (Ttuple ty_args)) in
TypeSet.elements (TypeSet.diff arg_vars res_vars)
in
let cstr =
{ cstr_name = Ident.name id;
cstr_res = ty_res;
cstr_existentials = existentials;
cstr_args = ty_args;
cstr_arity = List.length ty_args;
cstr_tag = tag;
cstr_consts = !num_consts;
cstr_nonconsts = !num_nonconsts;
cstr_normal = !num_normal;
cstr_private = priv;
cstr_generalized = ty_res_opt <> None
} in
(id, cstr) :: descr_rem in
describe_constructors 0 0 cstrs
let exception_descr path_exc decl =
{ cstr_name = Path.last path_exc;
cstr_res = Predef.type_exn;
cstr_existentials = [];
cstr_args = decl.exn_args;
cstr_arity = List.length decl.exn_args;
cstr_tag = Cstr_exception (path_exc, decl.exn_loc);
cstr_consts = -1;
cstr_nonconsts = -1;
cstr_private = Public;
cstr_normal = -1;
cstr_generalized = false }
let none = {desc = Ttuple []; level = -1; id = -1}
(* Clearly ill-formed type *)
let dummy_label =
{ lbl_name = ""; lbl_res = none; lbl_arg = none; lbl_mut = Immutable;
lbl_pos = (-1); lbl_all = [||]; lbl_repres = Record_regular;
lbl_private = Public }
let label_descrs ty_res lbls repres priv =
let all_labels = Array.create (List.length lbls) dummy_label in
let rec describe_labels num = function
[] -> []
| (id, mut_flag, ty_arg) :: rest ->
let lbl =
{ lbl_name = Ident.name id;
lbl_res = ty_res;
lbl_arg = ty_arg;
lbl_mut = mut_flag;
lbl_pos = num;
lbl_all = all_labels;
lbl_repres = repres;
lbl_private = priv } in
all_labels.(num) <- lbl;
(id, lbl) :: describe_labels (num+1) rest in
describe_labels 0 lbls
exception Constr_not_found
let rec find_constr tag num_const num_nonconst = function
[] ->
raise Constr_not_found
| (name, ([] as cstr),(_ as ret_type_opt)) :: rem ->
if tag = Cstr_constant num_const
then (name,cstr,ret_type_opt)
else find_constr tag (num_const + 1) num_nonconst rem
| (name, (_ as cstr),(_ as ret_type_opt)) :: rem ->
if tag = Cstr_block num_nonconst
then (name,cstr,ret_type_opt)
else find_constr tag num_const (num_nonconst + 1) rem
let find_constr_by_tag tag cstrlist =
find_constr tag 0 0 cstrlist