ocaml/typing/mtype.ml

128 lines
4.5 KiB
OCaml

(***********************************************************************)
(* *)
(* Objective Caml *)
(* *)
(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
(* *)
(* Copyright 1996 Institut National de Recherche en Informatique et *)
(* Automatique. Distributed only by permission. *)
(* *)
(***********************************************************************)
(* $Id$ *)
(* Operations on module types *)
open Path
open Types
let rec scrape env mty =
match mty with
Tmty_ident p ->
begin try
Env.find_modtype_expansion p env
with Not_found ->
mty
end
| _ -> mty
let rec strengthen env mty p =
match scrape env mty with
Tmty_signature sg ->
Tmty_signature(strengthen_sig env sg p)
| Tmty_functor(param, arg, res) ->
Tmty_functor(param, arg, strengthen env res (Papply(p, Pident param)))
| mty ->
mty
and strengthen_sig env sg p =
match sg with
[] -> []
| (Tsig_value(id, desc) as sigelt) :: rem ->
sigelt :: strengthen_sig env rem p
| Tsig_type(id, decl) :: rem ->
let newdecl =
match decl.type_manifest with
None ->
{ type_params = decl.type_params;
type_arity = decl.type_arity;
type_kind = decl.type_kind;
type_manifest = Some(Ctype.newgenty(
Tconstr(Pdot(p, Ident.name id, nopos),
decl.type_params,
ref Mnil))) }
| _ -> decl in
Tsig_type(id, newdecl) :: strengthen_sig env rem p
| (Tsig_exception(id, d) as sigelt) :: rem ->
sigelt :: strengthen_sig env rem p
| Tsig_module(id, mty) :: rem ->
Tsig_module(id, strengthen env mty (Pdot(p, Ident.name id, nopos))) ::
strengthen_sig (Env.add_module id mty env) rem p
(* Need to add the module in case it defines manifest module types *)
| Tsig_modtype(id, decl) :: rem ->
let newdecl =
match decl with
Tmodtype_abstract ->
Tmodtype_manifest(Tmty_ident(Pdot(p, Ident.name id, nopos)))
| Tmodtype_manifest _ ->
decl in
Tsig_modtype(id, newdecl) ::
strengthen_sig (Env.add_modtype id decl env) rem p
(* Need to add the module type in case it is manifest *)
| (Tsig_class(id, decl) as sigelt) :: rem ->
sigelt :: strengthen_sig env rem p
(* In nondep_supertype, env is only used for the type it assigns to id.
Hence there is no need to keep env up-to-date by adding the bindings
traversed. *)
type variance = Co | Contra | Strict
let nondep_supertype env mid mty =
let rec nondep_mty va mty =
match mty with
Tmty_ident p ->
if Path.isfree mid p then
nondep_mty va (Env.find_modtype_expansion p env)
else mty
| Tmty_signature sg ->
Tmty_signature(nondep_sig va sg)
| Tmty_functor(param, arg, res) ->
let var_inv =
match va with Co -> Contra | Contra -> Co | Strict -> Strict in
Tmty_functor(param, nondep_mty var_inv arg, nondep_mty va res)
and nondep_sig va = function
[] -> []
| item :: rem ->
let rem' = nondep_sig va rem in
match item with
Tsig_value(id, d) ->
Tsig_value(id, {val_type = Ctype.nondep_type env mid d.val_type;
val_kind = d.val_kind}) :: rem'
| Tsig_type(id, d) ->
Tsig_type(id, Ctype.nondep_type_decl env mid id (va = Co) d) :: rem'
| Tsig_exception(id, d) ->
Tsig_exception(id, List.map (Ctype.nondep_type env mid) d) :: rem'
| Tsig_module(id, mty) ->
Tsig_module(id, nondep_mty va mty) :: rem'
| Tsig_modtype(id, d) ->
begin try
Tsig_modtype(id, nondep_modtype_decl d) :: rem'
with Not_found ->
match va with
Co -> Tsig_modtype(id, Tmodtype_abstract) :: rem'
| _ -> raise Not_found
end
| Tsig_class(id, d) ->
Tsig_class(id, Ctype.nondep_class_type env mid d) :: rem'
and nondep_modtype_decl = function
Tmodtype_abstract -> Tmodtype_abstract
| Tmodtype_manifest mty -> Tmodtype_manifest(nondep_mty Strict mty)
in
nondep_mty Co mty