ocaml/typing/subst.ml

293 lines
9.6 KiB
OCaml

(***********************************************************************)
(* *)
(* Objective Caml *)
(* *)
(* 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. *)
(* *)
(***********************************************************************)
(* $Id$ *)
(* Substitutions *)
open Misc
open Path
open Types
open Btype
type t =
{ types: (Ident.t, Path.t) Tbl.t;
modules: (Ident.t, Path.t) Tbl.t;
modtypes: (Ident.t, module_type) Tbl.t;
for_saving: bool }
let identity =
{ types = Tbl.empty; modules = Tbl.empty; modtypes = Tbl.empty;
for_saving = false }
let add_type id p s = { s with types = Tbl.add id p s.types }
let add_module id p s = { s with modules = Tbl.add id p s.modules }
let add_modtype id ty s = { s with modtypes = Tbl.add id ty s.modtypes }
let for_saving s = { s with for_saving = true }
let rec module_path s = function
Pident id as p ->
begin try Tbl.find id s.modules with Not_found -> p end
| Pdot(p, n, pos) ->
Pdot(module_path s p, n, pos)
| Papply(p1, p2) ->
Papply(module_path s p1, module_path s p2)
let type_path s = function
Pident id as p ->
begin try Tbl.find id s.types with Not_found -> p end
| Pdot(p, n, pos) ->
Pdot(module_path s p, n, pos)
| Papply(p1, p2) ->
fatal_error "Subst.type_path"
(* Special type ids for saved signatures *)
let new_id = ref (-1)
let reset_for_saving () = new_id := -1
let newpersty desc =
decr new_id; { desc = desc; level = generic_level; id = !new_id }
(* Similar to [Ctype.nondep_type_rec]. *)
let rec typexp s ty =
let ty = repr ty in
match ty.desc with
Tvar | Tunivar ->
if s.for_saving || ty.id < 0 then
let ty' =
if s.for_saving then newpersty ty.desc else newty2 ty.level ty.desc
in
save_desc ty ty.desc; ty.desc <- Tsubst ty'; ty'
else ty
| Tsubst ty ->
ty
(* cannot do it, since it would omit subsitution
| Tvariant row when not (static_row row) ->
ty
*)
| _ ->
let desc = ty.desc in
save_desc ty desc;
(* Make a stub *)
let ty' = if s.for_saving then newpersty Tvar else newgenvar () in
ty.desc <- Tsubst ty';
ty'.desc <-
begin match desc with
| Tconstr(p, tl, abbrev) ->
Tconstr(type_path s p, List.map (typexp s) tl, ref Mnil)
| Tobject (t1, name) ->
Tobject (typexp s t1,
ref (match !name with
None -> None
| Some (p, tl) ->
Some (type_path s p, List.map (typexp s) tl)))
| Tvariant row ->
let row = row_repr row in
let more = repr row.row_more in
(* We must substitute in a subtle way *)
begin match more.desc with
Tsubst ({desc=Tvariant _} as ty2) ->
(* This variant type has been already copied *)
ty.desc <- Tsubst ty2; (* avoid Tlink in the new type *)
Tlink ty2
| _ ->
let static = static_row row in
(* Various cases for the row variable *)
let more' =
match more.desc with Tsubst ty -> ty
| _ ->
save_desc more more.desc;
if s.for_saving then newpersty more.desc else
if static then newgenvar () else more
in
(* Register new type first for recursion *)
more.desc <- ty.desc;
(* Return a new copy *)
let row =
copy_row (typexp s) true row (not s.for_saving) more' in
let row =
if s.for_saving then {row with row_bound = []} else row in
match row.row_name with
Some (p, tl) ->
Tvariant {row with row_name = Some (type_path s p, tl)}
| None ->
Tvariant row
end
| Tfield(label, kind, t1, t2) ->
begin match field_kind_repr kind with
Fpresent ->
Tfield(label, Fpresent, typexp s t1, typexp s t2)
| Fabsent ->
Tlink (typexp s t2)
| Fvar _ (* {contents = None} *) as k ->
let k = if s.for_saving then Fvar(ref None) else k in
Tfield(label, k, typexp s t1, typexp s t2)
end
| _ -> copy_type_desc (typexp s) desc
end;
ty'
(*
Always make a copy of the type. If this is not done, type levels
might not be correct.
*)
let type_expr s ty =
let ty' = typexp s ty in
cleanup_types ();
ty'
let type_declaration s decl =
let decl =
{ type_params = List.map (typexp s) decl.type_params;
type_arity = decl.type_arity;
type_kind =
begin match decl.type_kind with
Type_abstract -> Type_abstract
| Type_variant cstrs ->
Type_variant(
List.map (fun (n, args) -> (n, List.map (typexp s) args))
cstrs)
| Type_record(lbls, rep) ->
Type_record(
List.map (fun (n, mut, arg) -> (n, mut, typexp s arg))
lbls,
rep)
end;
type_manifest =
begin match decl.type_manifest with
None -> None
| Some ty -> Some(typexp s ty)
end;
type_variance = decl.type_variance;
}
in
cleanup_types ();
decl
let class_signature s sign =
{ cty_self = typexp s sign.cty_self;
cty_vars = Vars.map (function (m, t) -> (m, typexp s t)) sign.cty_vars;
cty_concr = sign.cty_concr }
let rec class_type s =
function
Tcty_constr (p, tyl, cty) ->
Tcty_constr (type_path s p, List.map (typexp s) tyl, class_type s cty)
| Tcty_signature sign ->
Tcty_signature (class_signature s sign)
| Tcty_fun (l, ty, cty) ->
Tcty_fun (l, typexp s ty, class_type s cty)
let class_declaration s decl =
let decl =
{ cty_params = List.map (typexp s) decl.cty_params;
cty_type = class_type s decl.cty_type;
cty_path = type_path s decl.cty_path;
cty_new =
begin match decl.cty_new with
None -> None
| Some ty -> Some (typexp s ty)
end }
in
(* Do not clean up if saving: next is cltype_declaration *)
if not s.for_saving then cleanup_types ();
decl
let cltype_declaration s decl =
let decl =
{ clty_params = List.map (typexp s) decl.clty_params;
clty_type = class_type s decl.clty_type;
clty_path = type_path s decl.clty_path }
in
(* Do not clean up if saving: next is type_declaration *)
if not s.for_saving then cleanup_types ();
decl
let class_type s cty =
let cty = class_type s cty in
cleanup_types ();
cty
let value_description s descr =
{ val_type = type_expr s descr.val_type;
val_kind = descr.val_kind }
let exception_declaration s tyl =
List.map (type_expr s) tyl
let rec rename_bound_idents s idents = function
[] -> (List.rev idents, s)
| Tsig_type(id, d) :: sg ->
let id' = Ident.rename id in
rename_bound_idents (add_type id (Pident id') s) (id' :: idents) sg
| Tsig_module(id, mty) :: sg ->
let id' = Ident.rename id in
rename_bound_idents (add_module id (Pident id') s) (id' :: idents) sg
| Tsig_modtype(id, d) :: sg ->
let id' = Ident.rename id in
rename_bound_idents (add_modtype id (Tmty_ident(Pident id')) s)
(id' :: idents) sg
| (Tsig_value(id, _) | Tsig_exception(id, _) |
Tsig_class(id, _) | Tsig_cltype(id, _)) :: sg ->
let id' = Ident.rename id in
rename_bound_idents s (id' :: idents) sg
let rec modtype s = function
Tmty_ident p as mty ->
begin match p with
Pident id ->
begin try Tbl.find id s.modtypes with Not_found -> mty end
| Pdot(p, n, pos) ->
Tmty_ident(Pdot(module_path s p, n, pos))
| Papply(p1, p2) ->
fatal_error "Subst.modtype"
end
| Tmty_signature sg ->
Tmty_signature(signature s sg)
| Tmty_functor(id, arg, res) ->
let id' = Ident.rename id in
Tmty_functor(id', modtype s arg,
modtype (add_module id (Pident id') s) res)
and signature s sg =
(* Components of signature may be mutually recursive (e.g. type declarations
or class and type declarations), so first build global renaming
substitution... *)
let (new_idents, s') = rename_bound_idents s [] sg in
(* ... then apply it to each signature component in turn *)
List.map2 (signature_component s') sg new_idents
and signature_component s comp newid =
match comp with
Tsig_value(id, d) ->
Tsig_value(newid, value_description s d)
| Tsig_type(id, d) ->
Tsig_type(newid, type_declaration s d)
| Tsig_exception(id, d) ->
Tsig_exception(newid, exception_declaration s d)
| Tsig_module(id, mty) ->
Tsig_module(newid, modtype s mty)
| Tsig_modtype(id, d) ->
Tsig_modtype(newid, modtype_declaration s d)
| Tsig_class(id, d) ->
Tsig_class(newid, class_declaration s d)
| Tsig_cltype(id, d) ->
Tsig_cltype(newid, cltype_declaration s d)
and modtype_declaration s = function
Tmodtype_abstract -> Tmodtype_abstract
| Tmodtype_manifest mty -> Tmodtype_manifest(modtype s mty)