ocaml/typing/subst.ml

558 lines
19 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 GNU Lesser General Public License version 2.1, with the *)
(* special exception on linking described in the file LICENSE. *)
(* *)
(**************************************************************************)
(* Substitutions *)
open Misc
open Path
open Types
open Btype
open Local_store
type type_replacement =
| Path of Path.t
| Type_function of { params : type_expr list; body : type_expr }
type t =
{ types: type_replacement Path.Map.t;
modules: Path.t Path.Map.t;
modtypes: module_type Ident.Map.t;
for_saving: bool;
}
let identity =
{ types = Path.Map.empty;
modules = Path.Map.empty;
modtypes = Ident.Map.empty;
for_saving = false;
}
let add_type_path id p s = { s with types = Path.Map.add id (Path p) s.types }
let add_type id p s = add_type_path (Pident id) p s
let add_type_function id ~params ~body s =
{ s with types = Path.Map.add id (Type_function { params; body }) s.types }
let add_module_path id p s = { s with modules = Path.Map.add id p s.modules }
let add_module id p s = add_module_path (Pident id) p s
let add_modtype id ty s = { s with modtypes = Ident.Map.add id ty s.modtypes }
let for_saving s = { s with for_saving = true }
let loc s x =
if s.for_saving && not !Clflags.keep_locs then Location.none else x
let remove_loc =
let open Ast_mapper in
{default_mapper with location = (fun _this _loc -> Location.none)}
let is_not_doc = function
| {Parsetree.attr_name = {Location.txt = "ocaml.doc"}; _} -> false
| {Parsetree.attr_name = {Location.txt = "ocaml.text"}; _} -> false
| {Parsetree.attr_name = {Location.txt = "doc"}; _} -> false
| {Parsetree.attr_name = {Location.txt = "text"}; _} -> false
| _ -> true
let attrs s x =
let x =
if s.for_saving && not !Clflags.keep_docs then
List.filter is_not_doc x
else x
in
if s.for_saving && not !Clflags.keep_locs
then remove_loc.Ast_mapper.attributes remove_loc x
else x
let rec module_path s path =
try Path.Map.find path s.modules
with Not_found ->
match path with
| Pident _ -> path
| Pdot(p, n) ->
Pdot(module_path s p, n)
| Papply(p1, p2) ->
Papply(module_path s p1, module_path s p2)
let modtype_path s = function
Pident id as p ->
begin try
match Ident.Map.find id s.modtypes with
| Mty_ident p -> p
| _ -> fatal_error "Subst.modtype_path"
with Not_found -> p end
| Pdot(p, n) ->
Pdot(module_path s p, n)
| Papply _ ->
fatal_error "Subst.modtype_path"
let type_path s path =
match Path.Map.find path s.types with
| Path p -> p
| Type_function _ -> assert false
| exception Not_found ->
match path with
| Pident _ -> path
| Pdot(p, n) ->
Pdot(module_path s p, n)
| Papply _ ->
fatal_error "Subst.type_path"
let type_path s p =
match Path.constructor_typath p with
| Regular p -> type_path s p
| Cstr (ty_path, cstr) -> Pdot(type_path s ty_path, cstr)
| LocalExt _ -> type_path s p
| Ext (p, cstr) -> Pdot(module_path s p, cstr)
let to_subst_by_type_function s p =
match Path.Map.find p s.types with
| Path _ -> false
| Type_function _ -> true
| exception Not_found -> false
(* Special type ids for saved signatures *)
let new_id = s_ref (-1)
let reset_for_saving () = new_id := -1
let newpersty desc =
decr new_id;
{ desc; level = generic_level; scope = Btype.lowest_level; id = !new_id }
(* ensure that all occurrences of 'Tvar None' are physically shared *)
let tvar_none = Tvar None
let tunivar_none = Tunivar None
let norm = function
| Tvar None -> tvar_none
| Tunivar None -> tunivar_none
| d -> d
let ctype_apply_env_empty = ref (fun _ -> assert false)
(* Similar to [Ctype.nondep_type_rec]. *)
let rec typexp copy_scope s ty =
let ty = repr ty in
match ty.desc with
Tvar _ | Tunivar _ as desc ->
if s.for_saving || ty.id < 0 then
let ty' =
if s.for_saving then newpersty (norm desc)
else newty2 ty.level desc
in
For_copy.save_desc copy_scope ty desc;
ty.desc <- Tsubst ty';
ty'
else ty
| Tsubst ty ->
ty
| Tfield (m, k, _t1, _t2) when not s.for_saving && m = dummy_method
&& field_kind_repr k <> Fabsent && (repr ty).level < generic_level ->
(* do not copy the type of self when it is not generalized *)
ty
(* cannot do it, since it would omit substitution
| Tvariant row when not (static_row row) ->
ty
*)
| _ ->
let desc = ty.desc in
For_copy.save_desc copy_scope ty desc;
let tm = row_of_type ty in
let has_fixed_row =
not (is_Tconstr ty) && is_constr_row ~allow_ident:false tm in
(* Make a stub *)
let ty' = if s.for_saving then newpersty (Tvar None) else newgenvar () in
ty'.scope <- ty.scope;
ty.desc <- Tsubst ty';
ty'.desc <-
begin if has_fixed_row then
match tm.desc with (* PR#7348 *)
Tconstr (Pdot(m,i), tl, _abbrev) ->
let i' = String.sub i 0 (String.length i - 4) in
Tconstr(type_path s (Pdot(m,i')), tl, ref Mnil)
| _ -> assert false
else match desc with
| Tconstr (p, args, _abbrev) ->
let args = List.map (typexp copy_scope s) args in
begin match Path.Map.find p s.types with
| exception Not_found -> Tconstr(type_path s p, args, ref Mnil)
| Path _ -> Tconstr(type_path s p, args, ref Mnil)
| Type_function { params; body } ->
Tlink (!ctype_apply_env_empty params body args)
end
| Tpackage(p, n, tl) ->
Tpackage(modtype_path s p, n, List.map (typexp copy_scope s) tl)
| Tobject (t1, name) ->
let t1' = typexp copy_scope s t1 in
let name' =
match !name with
| None -> None
| Some (p, tl) ->
if to_subst_by_type_function s p
then None
else Some (type_path s p, List.map (typexp copy_scope s) tl)
in
Tobject (t1', ref name')
| Tvariant row ->
let row = row_repr row in
let more = repr row.row_more in
(* We must substitute in a subtle way *)
(* Tsubst takes a tuple containing the row var and the variant *)
begin match more.desc with
Tsubst {desc = Ttuple [_;ty2]} ->
(* This variant type has been already copied *)
ty.desc <- Tsubst ty2; (* avoid Tlink in the new type *)
Tlink ty2
| _ ->
let dup =
s.for_saving || more.level = generic_level || static_row row ||
match more.desc with Tconstr _ -> true | _ -> false in
(* Various cases for the row variable *)
let more' =
match more.desc with
Tsubst ty -> ty
| Tconstr _ | Tnil -> typexp copy_scope s more
| Tunivar _ | Tvar _ ->
For_copy.save_desc copy_scope more more.desc;
if s.for_saving then newpersty (norm more.desc) else
if dup && is_Tvar more then newgenty more.desc else more
| _ -> assert false
in
(* Register new type first for recursion *)
more.desc <- Tsubst(newgenty(Ttuple[more';ty']));
(* Return a new copy *)
let row =
copy_row (typexp copy_scope s) true row (not dup) more' in
match row.row_name with
| Some (p, tl) ->
Tvariant {row with row_name =
if to_subst_by_type_function s p
then None
else Some (type_path s p, tl)}
| None ->
Tvariant row
end
| Tfield(_label, kind, _t1, t2) when field_kind_repr kind = Fabsent ->
Tlink (typexp copy_scope s t2)
| _ -> copy_type_desc (typexp copy_scope 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 =
For_copy.with_scope (fun copy_scope -> typexp copy_scope s ty)
let label_declaration copy_scope s l =
{
ld_id = l.ld_id;
ld_mutable = l.ld_mutable;
ld_type = typexp copy_scope s l.ld_type;
ld_loc = loc s l.ld_loc;
ld_attributes = attrs s l.ld_attributes;
ld_uid = l.ld_uid;
}
let constructor_arguments copy_scope s = function
| Cstr_tuple l ->
Cstr_tuple (List.map (typexp copy_scope s) l)
| Cstr_record l ->
Cstr_record (List.map (label_declaration copy_scope s) l)
let constructor_declaration copy_scope s c =
{
cd_id = c.cd_id;
cd_args = constructor_arguments copy_scope s c.cd_args;
cd_res = Option.map (typexp copy_scope s) c.cd_res;
cd_loc = loc s c.cd_loc;
cd_attributes = attrs s c.cd_attributes;
cd_uid = c.cd_uid;
}
let type_declaration' copy_scope s decl =
{ type_params = List.map (typexp copy_scope 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 (constructor_declaration copy_scope s) cstrs)
| Type_record(lbls, rep) ->
Type_record (List.map (label_declaration copy_scope s) lbls, rep)
| Type_open -> Type_open
end;
type_manifest =
begin
match decl.type_manifest with
None -> None
| Some ty -> Some(typexp copy_scope s ty)
end;
type_private = decl.type_private;
type_variance = decl.type_variance;
type_separability = decl.type_separability;
type_is_newtype = false;
type_expansion_scope = Btype.lowest_level;
type_loc = loc s decl.type_loc;
type_attributes = attrs s decl.type_attributes;
type_immediate = decl.type_immediate;
type_unboxed = decl.type_unboxed;
type_uid = decl.type_uid;
}
let type_declaration s decl =
For_copy.with_scope (fun copy_scope -> type_declaration' copy_scope s decl)
let class_signature copy_scope s sign =
{ csig_self = typexp copy_scope s sign.csig_self;
csig_vars =
Vars.map
(function (m, v, t) -> (m, v, typexp copy_scope s t)) sign.csig_vars;
csig_concr = sign.csig_concr;
csig_inher =
List.map
(fun (p, tl) -> (type_path s p, List.map (typexp copy_scope s) tl))
sign.csig_inher;
}
let rec class_type copy_scope s = function
| Cty_constr (p, tyl, cty) ->
let p' = type_path s p in
let tyl' = List.map (typexp copy_scope s) tyl in
let cty' = class_type copy_scope s cty in
Cty_constr (p', tyl', cty')
| Cty_signature sign ->
Cty_signature (class_signature copy_scope s sign)
| Cty_arrow (l, ty, cty) ->
Cty_arrow (l, typexp copy_scope s ty, class_type copy_scope s cty)
let class_declaration' copy_scope s decl =
{ cty_params = List.map (typexp copy_scope s) decl.cty_params;
cty_variance = decl.cty_variance;
cty_type = class_type copy_scope 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 copy_scope s ty)
end;
cty_loc = loc s decl.cty_loc;
cty_attributes = attrs s decl.cty_attributes;
cty_uid = decl.cty_uid;
}
let class_declaration s decl =
For_copy.with_scope (fun copy_scope -> class_declaration' copy_scope s decl)
let cltype_declaration' copy_scope s decl =
{ clty_params = List.map (typexp copy_scope s) decl.clty_params;
clty_variance = decl.clty_variance;
clty_type = class_type copy_scope s decl.clty_type;
clty_path = type_path s decl.clty_path;
clty_loc = loc s decl.clty_loc;
clty_attributes = attrs s decl.clty_attributes;
clty_uid = decl.clty_uid;
}
let cltype_declaration s decl =
For_copy.with_scope (fun copy_scope -> cltype_declaration' copy_scope s decl)
let class_type s cty =
For_copy.with_scope (fun copy_scope -> class_type copy_scope s cty)
let value_description' copy_scope s descr =
{ val_type = typexp copy_scope s descr.val_type;
val_kind = descr.val_kind;
val_loc = loc s descr.val_loc;
val_attributes = attrs s descr.val_attributes;
val_uid = descr.val_uid;
}
let value_description s descr =
For_copy.with_scope (fun copy_scope -> value_description' copy_scope s descr)
let extension_constructor' copy_scope s ext =
{ ext_type_path = type_path s ext.ext_type_path;
ext_type_params = List.map (typexp copy_scope s) ext.ext_type_params;
ext_args = constructor_arguments copy_scope s ext.ext_args;
ext_ret_type = Option.map (typexp copy_scope s) ext.ext_ret_type;
ext_private = ext.ext_private;
ext_attributes = attrs s ext.ext_attributes;
ext_loc = if s.for_saving then Location.none else ext.ext_loc;
ext_uid = ext.ext_uid;
}
let extension_constructor s ext =
For_copy.with_scope
(fun copy_scope -> extension_constructor' copy_scope s ext)
type scoping =
| Keep
| Make_local
| Rescope of int
let rename_bound_idents scoping s sg =
let rename =
let open Ident in
match scoping with
| Keep -> (fun id -> create_scoped ~scope:(scope id) (name id))
| Make_local -> Ident.rename
| Rescope scope -> (fun id -> create_scoped ~scope (name id))
in
let rec rename_bound_idents s sg = function
| [] -> sg, s
| Sig_type(id, td, rs, vis) :: rest ->
let id' = rename id in
rename_bound_idents
(add_type id (Pident id') s)
(Sig_type(id', td, rs, vis) :: sg)
rest
| Sig_module(id, pres, md, rs, vis) :: rest ->
let id' = rename id in
rename_bound_idents
(add_module id (Pident id') s)
(Sig_module (id', pres, md, rs, vis) :: sg)
rest
| Sig_modtype(id, mtd, vis) :: rest ->
let id' = rename id in
rename_bound_idents
(add_modtype id (Mty_ident(Pident id')) s)
(Sig_modtype(id', mtd, vis) :: sg)
rest
| Sig_class(id, cd, rs, vis) :: rest ->
(* cheat and pretend they are types cf. PR#6650 *)
let id' = rename id in
rename_bound_idents
(add_type id (Pident id') s)
(Sig_class(id', cd, rs, vis) :: sg)
rest
| Sig_class_type(id, ctd, rs, vis) :: rest ->
(* cheat and pretend they are types cf. PR#6650 *)
let id' = rename id in
rename_bound_idents
(add_type id (Pident id') s)
(Sig_class_type(id', ctd, rs, vis) :: sg)
rest
| Sig_value(id, vd, vis) :: rest ->
(* scope doesn't matter for value identifiers. *)
let id' = Ident.rename id in
rename_bound_idents s (Sig_value(id', vd, vis) :: sg) rest
| Sig_typext(id, ec, es, vis) :: rest ->
let id' = rename id in
rename_bound_idents s (Sig_typext(id',ec,es,vis) :: sg) rest
in
rename_bound_idents s [] sg
let rec modtype scoping s = function
Mty_ident p as mty ->
begin match p with
Pident id ->
begin try Ident.Map.find id s.modtypes with Not_found -> mty end
| Pdot(p, n) ->
Mty_ident(Pdot(module_path s p, n))
| Papply _ ->
fatal_error "Subst.modtype"
end
| Mty_signature sg ->
Mty_signature(signature scoping s sg)
| Mty_functor(Unit, res) ->
Mty_functor(Unit, modtype scoping s res)
| Mty_functor(Named (None, arg), res) ->
Mty_functor(Named (None, (modtype scoping s) arg), modtype scoping s res)
| Mty_functor(Named (Some id, arg), res) ->
let id' = Ident.rename id in
Mty_functor(Named (Some id', (modtype scoping s) arg),
modtype scoping (add_module id (Pident id') s) res)
| Mty_alias p ->
Mty_alias (module_path s p)
and signature scoping 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 (sg', s') = rename_bound_idents scoping s sg in
(* ... then apply it to each signature component in turn *)
For_copy.with_scope (fun copy_scope ->
List.rev_map (signature_item' copy_scope scoping s') sg'
)
and signature_item' copy_scope scoping s comp =
match comp with
Sig_value(id, d, vis) ->
Sig_value(id, value_description' copy_scope s d, vis)
| Sig_type(id, d, rs, vis) ->
Sig_type(id, type_declaration' copy_scope s d, rs, vis)
| Sig_typext(id, ext, es, vis) ->
Sig_typext(id, extension_constructor' copy_scope s ext, es, vis)
| Sig_module(id, pres, d, rs, vis) ->
Sig_module(id, pres, module_declaration scoping s d, rs, vis)
| Sig_modtype(id, d, vis) ->
Sig_modtype(id, modtype_declaration scoping s d, vis)
| Sig_class(id, d, rs, vis) ->
Sig_class(id, class_declaration' copy_scope s d, rs, vis)
| Sig_class_type(id, d, rs, vis) ->
Sig_class_type(id, cltype_declaration' copy_scope s d, rs, vis)
and signature_item scoping s comp =
For_copy.with_scope
(fun copy_scope -> signature_item' copy_scope scoping s comp)
and module_declaration scoping s decl =
{
md_type = modtype scoping s decl.md_type;
md_attributes = attrs s decl.md_attributes;
md_loc = loc s decl.md_loc;
md_uid = decl.md_uid;
}
and modtype_declaration scoping s decl =
{
mtd_type = Option.map (modtype scoping s) decl.mtd_type;
mtd_attributes = attrs s decl.mtd_attributes;
mtd_loc = loc s decl.mtd_loc;
mtd_uid = decl.mtd_uid;
}
(* For every binding k |-> d of m1, add k |-> f d to m2
and return resulting merged map. *)
let merge_tbls f m1 m2 =
Ident.Map.fold (fun k d accu -> Ident.Map.add k (f d) accu) m1 m2
let merge_path_maps f m1 m2 =
Path.Map.fold (fun k d accu -> Path.Map.add k (f d) accu) m1 m2
let type_replacement s = function
| Path p -> Path (type_path s p)
| Type_function { params; body } ->
For_copy.with_scope (fun copy_scope ->
let params = List.map (typexp copy_scope s) params in
let body = typexp copy_scope s body in
Type_function { params; body })
(* Composition of substitutions:
apply (compose s1 s2) x = apply s2 (apply s1 x) *)
let compose s1 s2 =
{ types = merge_path_maps (type_replacement s2) s1.types s2.types;
modules = merge_path_maps (module_path s2) s1.modules s2.modules;
modtypes = merge_tbls (modtype Keep s2) s1.modtypes s2.modtypes;
for_saving = s1.for_saving || s2.for_saving;
}