ocaml/typing/typemod.ml

559 lines
21 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. *)
(* *)
(***********************************************************************)
(* $Id$ *)
(* Type-checking of the module language *)
open Misc
open Longident
open Path
open Parsetree
open Types
open Typedtree
open Format
type error =
Unbound_module of Longident.t
| Unbound_modtype of Longident.t
| Cannot_apply of module_type
| Not_included of Includemod.error list
| Cannot_eliminate_dependency of module_type
| Signature_expected
| Structure_expected of module_type
| With_no_component of Longident.t
| With_mismatch of Longident.t * Includemod.error list
| Repeated_name of string * string
| Non_generalizable of type_expr
| Non_generalizable_class of Ident.t * class_declaration
| Non_generalizable_module of module_type
exception Error of Location.t * error
(* Extract a signature from a module type *)
let extract_sig env loc mty =
match Mtype.scrape env mty with
Tmty_signature sg -> sg
| _ -> raise(Error(loc, Signature_expected))
let extract_sig_open env loc mty =
match Mtype.scrape env mty with
Tmty_signature sg -> sg
| _ -> raise(Error(loc, Structure_expected mty))
(* Lookup the type of a module path *)
let type_module_path env loc lid =
try
Env.lookup_module lid env
with Not_found ->
raise(Error(loc, Unbound_module lid))
(* Merge one "with" constraint in a signature *)
let merge_constraint initial_env loc sg lid constr =
let rec merge env sg namelist =
match (sg, namelist, constr) with
([], _, _) ->
raise(Error(loc, With_no_component lid))
| (Tsig_type(id, decl) :: rem, [s], Pwith_type sdecl)
when Ident.name id = s ->
let newdecl = Typedecl.transl_with_constraint initial_env sdecl in
Includemod.type_declarations env id newdecl decl;
Tsig_type(id, newdecl) :: rem
| (Tsig_module(id, mty) :: rem, [s], Pwith_module lid)
when Ident.name id = s ->
let (path, mty') = type_module_path initial_env loc lid in
let newmty = Mtype.strengthen env mty' path in
ignore(Includemod.modtypes env newmty mty);
Tsig_module(id, newmty) :: rem
| (Tsig_module(id, mty) :: rem, s :: namelist, _) when Ident.name id = s ->
let newsg = merge env (extract_sig env loc mty) namelist in
Tsig_module(id, Tmty_signature newsg) :: rem
| (item :: rem, _, _) ->
item :: merge (Env.add_item item env) rem namelist in
try
merge initial_env sg (Longident.flatten lid)
with Includemod.Error explanation ->
raise(Error(loc, With_mismatch(lid, explanation)))
(* Auxiliaries for checking uniqueness of names in signatures and structures *)
module StringSet = Set.Make(struct type t = string let compare = compare end)
let check cl loc set_ref name =
if StringSet.mem name !set_ref
then raise(Error(loc, Repeated_name(cl, name)))
else set_ref := StringSet.add name !set_ref
let check_sig_item type_names module_names modtype_names loc = function
Tsig_type(id, _) ->
check "type" loc type_names (Ident.name id)
| Tsig_module(id, _) ->
check "module" loc module_names (Ident.name id)
| Tsig_modtype(id, _) ->
check "module type" loc modtype_names (Ident.name id)
| _ -> ()
(* Check and translate a module type expression *)
let rec transl_modtype env smty =
match smty.pmty_desc with
Pmty_ident lid ->
begin try
let (path, info) = Env.lookup_modtype lid env in
Tmty_ident path
with Not_found ->
raise(Error(smty.pmty_loc, Unbound_modtype lid))
end
| Pmty_signature ssg ->
Tmty_signature(transl_signature env ssg)
| Pmty_functor(param, sarg, sres) ->
let arg = transl_modtype env sarg in
let (id, newenv) = Env.enter_module param arg env in
let res = transl_modtype newenv sres in
Tmty_functor(id, arg, res)
| Pmty_with(sbody, constraints) ->
let body = transl_modtype env sbody in
let init_sg = extract_sig env sbody.pmty_loc body in
let final_sg =
List.fold_left
(fun sg (lid, sdecl) ->
merge_constraint env smty.pmty_loc sg lid sdecl)
init_sg constraints in
Tmty_signature final_sg
and transl_signature env sg =
let type_names = ref StringSet.empty
and module_names = ref StringSet.empty
and modtype_names = ref StringSet.empty in
let rec transl_sig env sg =
Ctype.init_def(Ident.current_time());
match sg with
[] -> []
| item :: srem ->
match item.psig_desc with
| Psig_value(name, sdesc) ->
let desc = Typedecl.transl_value_decl env sdesc in
let (id, newenv) = Env.enter_value name desc env in
let rem = transl_sig newenv srem in
Tsig_value(id, desc) :: rem
| Psig_type sdecls ->
List.iter
(fun (name, decl) -> check "type" item.psig_loc type_names name)
sdecls;
let (decls, newenv) = Typedecl.transl_type_decl env sdecls in
let rem = transl_sig newenv srem in
map_end (fun (id, info) -> Tsig_type(id, info)) decls rem
| Psig_exception(name, sarg) ->
let arg = Typedecl.transl_exception env sarg in
let (id, newenv) = Env.enter_exception name arg env in
let rem = transl_sig newenv srem in
Tsig_exception(id, arg) :: rem
| Psig_module(name, smty) ->
check "module type" item.psig_loc modtype_names name;
let mty = transl_modtype env smty in
let (id, newenv) = Env.enter_module name mty env in
let rem = transl_sig newenv srem in
Tsig_module(id, mty) :: rem
| Psig_modtype(name, sinfo) ->
let info = transl_modtype_info env sinfo in
let (id, newenv) = Env.enter_modtype name info env in
let rem = transl_sig newenv srem in
Tsig_modtype(id, info) :: rem
| Psig_open lid ->
let (path, mty) = type_module_path env item.psig_loc lid in
let sg = extract_sig_open env item.psig_loc mty in
let newenv = Env.open_signature path sg env in
transl_sig newenv srem
| Psig_include smty ->
let mty = transl_modtype env smty in
let sg = extract_sig env smty.pmty_loc mty in
List.iter
(check_sig_item type_names module_names modtype_names
item.psig_loc)
sg;
let newenv = Env.add_signature sg env in
let rem = transl_sig newenv srem in
sg @ rem
| Psig_class cl ->
List.iter
(fun {pci_name = name} ->
check "type" item.psig_loc type_names name)
cl;
let (classes, newenv) = Typeclass.class_descriptions env cl in
let rem = transl_sig newenv srem in
List.flatten
(map_end
(fun (i, d, i', d', i'', d'', i''', d''', _, _, _) ->
[Tsig_class(i, d); Tsig_cltype(i', d');
Tsig_type(i'', d''); Tsig_type(i''', d''')])
classes [rem])
| Psig_class_type cl ->
List.iter
(fun {pci_name = name} ->
check "type" item.psig_loc type_names name)
cl;
let (classes, newenv) = Typeclass.class_type_declarations env cl in
let rem = transl_sig newenv srem in
List.flatten
(map_end
(fun (i, d, i', d', i'', d'') ->
[Tsig_cltype(i, d);
Tsig_type(i', d'); Tsig_type(i'', d'')])
classes [rem])
in transl_sig env sg
and transl_modtype_info env sinfo =
match sinfo with
Pmodtype_abstract ->
Tmodtype_abstract
| Pmodtype_manifest smty ->
Tmodtype_manifest(transl_modtype env smty)
(* Try to convert a module expression to a module path. *)
exception Not_a_path
let rec path_of_module mexp =
match mexp.mod_desc with
Tmod_ident p -> p
| Tmod_apply(funct, arg, coercion) ->
Papply(path_of_module funct, path_of_module arg)
| _ -> raise Not_a_path
(* Check that all type and module identifiers in a structure have
distinct names (so that access by named paths is unambiguous). *)
let check_unique_names sg =
let type_names = ref StringSet.empty
and module_names = ref StringSet.empty
and modtype_names = ref StringSet.empty in
let check_item item =
match item.pstr_desc with
Pstr_eval exp -> ()
| Pstr_value(rec_flag, exps) -> ()
| Pstr_primitive(name, desc) -> ()
| Pstr_type name_decl_list ->
List.iter
(fun (name, decl) -> check "type" item.pstr_loc type_names name)
name_decl_list
| Pstr_exception(name, decl) -> ()
| Pstr_exn_rebind(name, path) -> ()
| Pstr_module(name, smod) ->
check "module" item.pstr_loc module_names name
| Pstr_modtype(name, decl) ->
check "module type" item.pstr_loc modtype_names name
| Pstr_open lid -> ()
| Pstr_class decl ->
List.iter
(fun {pci_name = name} ->
check "type" item.pstr_loc type_names name)
decl
| Pstr_class_type decl ->
List.iter
(fun {pci_name = name} ->
check "type" item.pstr_loc type_names name)
decl
in
List.iter check_item sg
(* Check that all core type schemes in a structure are closed *)
let rec closed_modtype = function
Tmty_ident p -> true
| Tmty_signature sg -> List.for_all closed_signature_item sg
| Tmty_functor(id, param, body) -> closed_modtype body
and closed_signature_item = function
Tsig_value(id, desc) -> Ctype.closed_schema desc.val_type
| Tsig_module(id, mty) -> closed_modtype mty
| _ -> true
let check_nongen_scheme env = function
Tstr_value(rec_flag, pat_exp_list) ->
List.iter
(fun (pat, exp) ->
if not (Ctype.closed_schema exp.exp_type) then
raise(Error(exp.exp_loc, Non_generalizable exp.exp_type)))
pat_exp_list
| Tstr_module(id, md) ->
if not (closed_modtype md.mod_type) then
raise(Error(md.mod_loc, Non_generalizable_module md.mod_type))
| _ -> ()
let check_nongen_schemes env str =
List.iter (check_nongen_scheme env) str
(* Type a module value expression *)
let rec type_module env smod =
match smod.pmod_desc with
Pmod_ident lid ->
let (path, mty) = type_module_path env smod.pmod_loc lid in
{ mod_desc = Tmod_ident path;
mod_type = Mtype.strengthen env mty path;
mod_env = env;
mod_loc = smod.pmod_loc }
| Pmod_structure sstr ->
let (str, sg, finalenv) = type_structure env sstr in
{ mod_desc = Tmod_structure str;
mod_type = Tmty_signature sg;
mod_env = env;
mod_loc = smod.pmod_loc }
| Pmod_functor(name, smty, sbody) ->
let mty = transl_modtype env smty in
let (id, newenv) = Env.enter_module name mty env in
let body = type_module newenv sbody in
{ mod_desc = Tmod_functor(id, mty, body);
mod_type = Tmty_functor(id, mty, body.mod_type);
mod_env = env;
mod_loc = smod.pmod_loc }
| Pmod_apply(sfunct, sarg) ->
let funct = type_module env sfunct in
let arg = type_module env sarg in
begin match Mtype.scrape env funct.mod_type with
Tmty_functor(param, mty_param, mty_res) as mty_functor ->
let coercion =
try
Includemod.modtypes env arg.mod_type mty_param
with Includemod.Error msg ->
raise(Error(sarg.pmod_loc, Not_included msg)) in
let mty_appl =
try
let path = path_of_module arg in
Subst.modtype (Subst.add_module param path Subst.identity)
mty_res
with Not_a_path ->
try
Mtype.nondep_supertype
(Env.add_module param arg.mod_type env) param mty_res
with Not_found ->
raise(Error(smod.pmod_loc,
Cannot_eliminate_dependency mty_functor)) in
{ mod_desc = Tmod_apply(funct, arg, coercion);
mod_type = mty_appl;
mod_env = env;
mod_loc = smod.pmod_loc }
| _ ->
raise(Error(sfunct.pmod_loc, Cannot_apply funct.mod_type))
end
| Pmod_constraint(sarg, smty) ->
let arg = type_module env sarg in
let mty = transl_modtype env smty in
let coercion =
try
Includemod.modtypes env arg.mod_type mty
with Includemod.Error msg ->
raise(Error(sarg.pmod_loc, Not_included msg)) in
{ mod_desc = Tmod_constraint(arg, mty, coercion);
mod_type = mty;
mod_env = env;
mod_loc = smod.pmod_loc }
and type_structure env sstr =
check_unique_names sstr;
type_struct env sstr
and type_struct env sstr =
Ctype.init_def(Ident.current_time());
match sstr with
[] ->
([], [], env)
| {pstr_desc = Pstr_eval sexpr} :: srem ->
let expr = Typecore.type_expression env sexpr in
let (str_rem, sig_rem, final_env) = type_struct env srem in
(Tstr_eval expr :: str_rem, sig_rem, final_env)
| {pstr_desc = Pstr_value(rec_flag, sdefs)} :: srem ->
let (defs, newenv) =
Typecore.type_binding env rec_flag sdefs in
let (str_rem, sig_rem, final_env) = type_struct newenv srem in
let bound_idents = let_bound_idents defs in
let make_sig_value id =
Tsig_value(id, Env.find_value (Pident id) newenv) in
(Tstr_value(rec_flag, defs) :: str_rem,
map_end make_sig_value bound_idents sig_rem,
final_env)
| {pstr_desc = Pstr_primitive(name, sdesc)} :: srem ->
let desc = Typedecl.transl_value_decl env sdesc in
let (id, newenv) = Env.enter_value name desc env in
let (str_rem, sig_rem, final_env) = type_struct newenv srem in
(Tstr_primitive(id, desc) :: str_rem,
Tsig_value(id, desc) :: sig_rem,
final_env)
| {pstr_desc = Pstr_type sdecls} :: srem ->
let (decls, newenv) = Typedecl.transl_type_decl env sdecls in
let (str_rem, sig_rem, final_env) = type_struct newenv srem in
(Tstr_type decls :: str_rem,
map_end (fun (id, info) -> Tsig_type(id, info)) decls sig_rem,
final_env)
| {pstr_desc = Pstr_exception(name, sarg)} :: srem ->
let arg = Typedecl.transl_exception env sarg in
let (id, newenv) = Env.enter_exception name arg env in
let (str_rem, sig_rem, final_env) = type_struct newenv srem in
(Tstr_exception(id, arg) :: str_rem,
Tsig_exception(id, arg) :: sig_rem,
final_env)
| {pstr_desc = Pstr_exn_rebind(name, longid); pstr_loc = loc} :: srem ->
let (path, arg) = Typedecl.transl_exn_rebind env loc longid in
let (id, newenv) = Env.enter_exception name arg env in
let (str_rem, sig_rem, final_env) = type_struct newenv srem in
(Tstr_exn_rebind(id, path) :: str_rem,
Tsig_exception(id, arg) :: sig_rem,
final_env)
| {pstr_desc = Pstr_module(name, smodl)} :: srem ->
let modl = type_module env smodl in
let (id, newenv) = Env.enter_module name modl.mod_type env in
let (str_rem, sig_rem, final_env) = type_struct newenv srem in
(Tstr_module(id, modl) :: str_rem,
Tsig_module(id, modl.mod_type) :: sig_rem,
final_env)
| {pstr_desc = Pstr_modtype(name, smty)} :: srem ->
let mty = transl_modtype env smty in
let (id, newenv) = Env.enter_modtype name (Tmodtype_manifest mty) env in
let (str_rem, sig_rem, final_env) = type_struct newenv srem in
(Tstr_modtype(id, mty) :: str_rem,
Tsig_modtype(id, Tmodtype_manifest mty) :: sig_rem,
final_env)
| {pstr_desc = Pstr_open lid; pstr_loc = loc} :: srem ->
let (path, mty) = type_module_path env loc lid in
let sg = extract_sig_open env loc mty in
type_struct (Env.open_signature path sg env) srem
| {pstr_desc = Pstr_class cl} :: srem ->
let (classes, new_env) = Typeclass.class_declarations env cl in
let (str_rem, sig_rem, final_env) = type_struct new_env srem in
(Tstr_class
(List.map (fun (i, _,_,_,_,_,_,_, s, m, c) ->
(i, s, m, c)) classes) ::
Tstr_cltype
(List.map (fun (_,_, i, d, _,_,_,_,_,_,_) -> (i, d)) classes) ::
Tstr_type
(List.map (fun (_,_,_,_, i, d, _,_,_,_,_) -> (i, d)) classes) ::
Tstr_type
(List.map (fun (_,_,_,_,_,_, i, d, _,_,_) -> (i, d)) classes) ::
str_rem,
List.flatten
(map_end
(fun (i, d, i', d', i'', d'', i''', d''', _, _, _) ->
[Tsig_class(i, d); Tsig_cltype(i', d');
Tsig_type(i'', d''); Tsig_type(i''', d''')])
classes [sig_rem]),
final_env)
| {pstr_desc = Pstr_class_type cl} :: srem ->
let (classes, new_env) = Typeclass.class_type_declarations env cl in
let (str_rem, sig_rem, final_env) = type_struct new_env srem in
(Tstr_cltype
(List.map (fun (i, d, _, _, _, _) -> (i, d)) classes) ::
Tstr_type
(List.map (fun (_, _, i, d, _, _) -> (i, d)) classes) ::
Tstr_type
(List.map (fun (_, _, _, _, i, d) -> (i, d)) classes) ::
str_rem,
List.flatten
(map_end
(fun (i, d, i', d', i'', d'') ->
[Tsig_cltype(i, d); Tsig_type(i', d'); Tsig_type(i'', d'')])
classes [sig_rem]),
final_env)
(* Fill in the forward declaration *)
let _ =
Typecore.type_module := type_module
(* Normalize types in a signature *)
let rec normalize_modtype env = function
Tmty_ident p -> ()
| Tmty_signature sg -> normalize_signature env sg
| Tmty_functor(id, param, body) -> normalize_modtype env body
and normalize_signature env = List.iter (normalize_signature_item env)
and normalize_signature_item env = function
Tsig_value(id, desc) -> Ctype.normalize_type env desc.val_type
| Tsig_module(id, mty) -> normalize_modtype env mty
| _ -> ()
(* Typecheck an implementation file *)
let type_implementation sourcefile prefixname modulename initial_env ast =
let (str, sg, finalenv) = type_structure initial_env ast in
if !Clflags.print_types then
fprintf err_formatter "%a@." Printtyp.signature sg;
let coercion =
if Sys.file_exists (prefixname ^ !Config.interface_suffix) then begin
let intf_file =
try find_in_path !Config.load_path (prefixname ^ ".cmi")
with Not_found -> prefixname ^ ".cmi" in
let dclsig = Env.read_signature modulename intf_file in
Includemod.compunit sourcefile sg intf_file dclsig
end else begin
check_nongen_schemes finalenv str;
normalize_signature finalenv sg;
Env.save_signature sg modulename (prefixname ^ ".cmi");
Tcoerce_none
end in
(str, coercion)
(* Error report *)
open Printtyp
let report_error ppf = function
| Unbound_module lid -> fprintf ppf "Unbound module %a" longident lid
| Unbound_modtype lid -> fprintf ppf "Unbound module type %a" longident lid
| Cannot_apply mty ->
fprintf ppf
"@[This module is not a functor; it has type@ %a@]" modtype mty
| Not_included errs ->
fprintf ppf
"@[<v>Signature mismatch:@ %a@]" Includemod.report_error errs
| Cannot_eliminate_dependency mty ->
fprintf ppf
"@[This functor has type@ %a@ \
The parameter cannot be eliminated in the result type.@ \
Please bind the argument to a module identifier.@]" modtype mty
| Signature_expected -> fprintf ppf "This module type is not a signature"
| Structure_expected mty ->
fprintf ppf
"@[This module is not a structure; it has type@ %a" modtype mty
| With_no_component lid ->
fprintf ppf
"@[The signature constrained by `with' has no component named %a@]"
longident lid
| With_mismatch(lid, explanation) ->
fprintf ppf
"@[<v>
@[In this `with' constraint, the new definition of %a@ \
does not match its original definition@ \
in the constrained signature:@]@ \
%a@]"
longident lid Includemod.report_error explanation
| Repeated_name(kind, name) ->
fprintf ppf
"@[Multiple definition of the %s name %s.@ \
Names must be unique in a given structure or signature.@]" kind name
| Non_generalizable typ ->
fprintf ppf
"@[The type of this expression,@ %a,@ \
contains type variables that cannot be generalized@]" type_scheme typ
| Non_generalizable_class (id, desc) ->
fprintf ppf
"@[The type of this class,@ %a,@ \
contains type variables that cannot be generalized@]"
(class_declaration id) desc
| Non_generalizable_module mty ->
fprintf ppf
"@[The type of this module,@ %a,@ \
contains type variables that cannot be generalized@]" modtype mty