ocaml/typing/typeclass.ml

1234 lines
42 KiB
OCaml

(***********************************************************************)
(* *)
(* Objective Caml *)
(* *)
(* Jerome Vouillon, 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. *)
(* *)
(***********************************************************************)
(* $Id$ *)
open Misc
open Parsetree
open Asttypes
open Types
open Typedtree
open Typecore
open Typetexp
type error =
Unconsistent_constraint of (type_expr * type_expr) list
| Method_type_mismatch of string * (type_expr * type_expr) list
| Structure_expected of class_type
| Cannot_apply of class_type
| Apply_wrong_label of label
| Pattern_type_clash of type_expr
| Repeated_parameter
| Unbound_class of Longident.t
| Unbound_class_2 of Longident.t
| Unbound_class_type of Longident.t
| Unbound_class_type_2 of Longident.t
| Abbrev_type_clash of type_expr * type_expr * type_expr
| Constructor_type_mismatch of string * (type_expr * type_expr) list
| Virtual_class of bool * string list
| Parameter_arity_mismatch of Longident.t * int * int
| Parameter_mismatch of (type_expr * type_expr) list
| Bad_parameters of Ident.t * type_expr * type_expr
| Class_match_failure of Ctype.class_match_failure list
| Unbound_val of string
| Unbound_type_var of (unit -> unit) * Ctype.closed_class_failure
| Make_nongen_seltype of type_expr
| Non_generalizable_class of Ident.t * Types.class_declaration
exception Error of Location.t * error
(**********************)
(* Useful constants *)
(**********************)
(*
Self type have a dummy private method, thus preventing it to become
closed.
*)
let dummy_method = "*dummy method*"
(*
Path associated to the temporary class type of a class being typed
(its constructor is not available).
*)
let unbound_class = Path.Pident (Ident.create "")
(************************************)
(* Some operations on class types *)
(************************************)
(* Fully expand the head of a class type *)
let rec scrape_class_type =
function
Tcty_constr (_, _, cty) -> scrape_class_type cty
| cty -> cty
(* Generalize a class type *)
let rec generalize_class_type =
function
Tcty_constr (_, params, cty) ->
List.iter Ctype.generalize params;
generalize_class_type cty
| Tcty_signature {cty_self = sty; cty_vars = vars } ->
Ctype.generalize sty;
Vars.iter (fun _ (_, ty) -> Ctype.generalize ty) vars
| Tcty_fun (_, ty, cty) ->
Ctype.generalize ty;
generalize_class_type cty
(* Return the virtual methods of a class type *)
let virtual_methods cty =
let sign = Ctype.signature_of_class_type cty in
let (fields, _) = Ctype.flatten_fields (Ctype.object_fields sign.cty_self) in
List.fold_left
(fun virt (lab, _, _) ->
if lab = dummy_method then virt else
if Concr.mem lab sign.cty_concr then virt else
lab::virt)
[] fields
(* Return the constructor type associated to a class type *)
let rec constructor_type constr cty =
match cty with
Tcty_constr (_, _, cty) ->
constructor_type constr cty
| Tcty_signature sign ->
constr
| Tcty_fun (l, ty, cty) ->
Ctype.newty (Tarrow (l, ty, constructor_type constr cty))
let rec class_body cty =
match cty with
Tcty_constr (_, _, cty') ->
cty (* Only class bodies can be abbreviated *)
| Tcty_signature sign ->
cty
| Tcty_fun (_, ty, cty) ->
class_body cty
let rec extract_constraints cty =
let sign = Ctype.signature_of_class_type cty in
(Vars.fold (fun lab _ vars -> lab :: vars) sign.cty_vars [],
begin let (fields, _) =
Ctype.flatten_fields (Ctype.object_fields sign.cty_self)
in
List.fold_left
(fun meths (lab, _, _) ->
if lab = dummy_method then meths else lab::meths)
[] fields
end,
sign.cty_concr)
let rec abbreviate_class_type path params cty =
match cty with
Tcty_constr (_, _, _) | Tcty_signature _ ->
Tcty_constr (path, params, cty)
| Tcty_fun (l, ty, cty) ->
Tcty_fun (l, ty, abbreviate_class_type path params cty)
let rec closed_class_type =
function
Tcty_constr (_, params, _) ->
List.for_all Ctype.closed_schema params
| Tcty_signature sign ->
Ctype.closed_schema sign.cty_self
&&
Vars.fold (fun _ (_, ty) cc -> Ctype.closed_schema ty && cc)
sign.cty_vars
true
| Tcty_fun (_, ty, cty) ->
Ctype.closed_schema ty
&&
closed_class_type cty
let closed_class cty =
List.for_all Ctype.closed_schema cty.cty_params
&&
closed_class_type cty.cty_type
let rec limited_generalize rv =
function
Tcty_constr (path, params, cty) ->
List.iter (Ctype.limited_generalize rv) params;
limited_generalize rv cty
| Tcty_signature sign ->
Ctype.limited_generalize rv sign.cty_self;
Vars.iter (fun _ (_, ty) -> Ctype.limited_generalize rv ty)
sign.cty_vars
| Tcty_fun (_, ty, cty) ->
Ctype.limited_generalize rv ty;
limited_generalize rv cty
(***********************************)
(* Primitives for typing classes *)
(***********************************)
(* Enter a value in the method environment only *)
let enter_met_env lab kind ty val_env met_env par_env =
let (id, val_env) =
Env.enter_value lab {val_type = ty; val_kind = Val_unbound} val_env
in
(id, val_env,
Env.add_value id {val_type = ty; val_kind = kind} met_env,
Env.add_value id {val_type = ty; val_kind = Val_unbound} par_env)
(* Enter an instance variable in the environment *)
let enter_val cl_num vars lab mut ty val_env met_env par_env =
let (id, val_env, met_env, par_env) as result =
enter_met_env lab (Val_ivar (mut, cl_num)) ty val_env met_env par_env
in
vars := Vars.add lab (id, mut, ty) !vars;
result
let inheritance impl self_type env concr_meths loc parent =
match scrape_class_type parent with
Tcty_signature cl_sig ->
(* Methods *)
begin try
Ctype.unify env self_type cl_sig.cty_self
with Ctype.Unify trace ->
match trace with
_::_::_::({desc = Tfield(n, _, _, _)}, _)::rem ->
raise(Error(loc, Method_type_mismatch (n, rem)))
| _ ->
assert false
end;
if impl then begin
let overridings = Concr.inter cl_sig.cty_concr concr_meths in
if not (Concr.is_empty overridings) then begin
Location.print_warning loc
(Warnings.Method_override (Concr.elements overridings))
end
end;
let concr_meths = Concr.union cl_sig.cty_concr concr_meths in
(cl_sig, concr_meths)
| _ ->
raise(Error(loc, Structure_expected parent))
let virtual_method val_env meths self_type lab priv sty loc =
let (_, ty') =
Ctype.filter_self_method val_env lab priv meths self_type
in
let ty = transl_simple_type val_env false sty in
try Ctype.unify val_env ty ty' with Ctype.Unify trace ->
raise(Error(loc, Method_type_mismatch (lab, trace)))
let type_constraint val_env sty sty' loc =
let ty = transl_simple_type val_env false sty in
let ty' = transl_simple_type val_env false sty' in
try Ctype.unify val_env ty ty' with Ctype.Unify trace ->
raise(Error(loc, Unconsistent_constraint trace))
let mkpat d = { ppat_desc = d; ppat_loc = Location.none }
let make_method cl_num expr =
{ pexp_desc =
Pexp_function ("", None,
[mkpat (Ppat_alias (mkpat(Ppat_var "self-*"),
"self-" ^ cl_num)),
expr]);
pexp_loc = expr.pexp_loc }
(*******************************)
let rec class_type_field env self_type meths (val_sig, concr_meths) =
function
Pctf_inher sparent ->
let parent = class_type env sparent in
let (cl_sig, concr_meths) =
inheritance false self_type env concr_meths sparent.pcty_loc parent
in
let val_sig =
Vars.fold
(fun lab (mut, ty) val_sig -> Vars.add lab (mut, ty) val_sig)
cl_sig.cty_vars val_sig
in
(val_sig, concr_meths)
| Pctf_val (lab, mut, sty_opt, loc) ->
let (mut, ty) =
match sty_opt with
None ->
let (mut', ty) =
try Vars.find lab val_sig with Not_found ->
raise(Error(loc, Unbound_val lab))
in
(if mut = Mutable then mut' else Immutable), ty
| Some sty ->
mut, transl_simple_type env false sty
in
(Vars.add lab (mut, ty) val_sig, concr_meths)
| Pctf_virt (lab, priv, sty, loc) ->
virtual_method env meths self_type lab priv sty loc;
(val_sig, concr_meths)
| Pctf_meth (lab, priv, sty, loc) ->
virtual_method env meths self_type lab priv sty loc;
(val_sig, Concr.add lab concr_meths)
| Pctf_cstr (sty, sty', loc) ->
type_constraint env sty sty' loc;
(val_sig, concr_meths)
and class_signature env sty sign =
let meths = ref Meths.empty in
let self_type = transl_simple_type env false sty in
(* Check that the binder is a correct type, and introduce a dummy
method preventing self type from being closed. *)
begin try
Ctype.unify env
(Ctype.filter_method env dummy_method Private self_type)
(Ctype.newty (Ttuple []))
with Ctype.Unify _ ->
raise(Error(sty.ptyp_loc, Pattern_type_clash self_type))
end;
(* Class type fields *)
let (val_sig, concr_meths) =
List.fold_left (class_type_field env self_type meths)
(Vars.empty, Concr.empty)
sign
in
{cty_self = self_type;
cty_vars = val_sig;
cty_concr = concr_meths }
and class_type env scty =
match scty.pcty_desc with
Pcty_constr (lid, styl) ->
let (path, decl) =
try Env.lookup_cltype lid env with Not_found ->
raise(Error(scty.pcty_loc, Unbound_class_type lid))
in
if Path.same decl.clty_path unbound_class then
raise(Error(scty.pcty_loc, Unbound_class_type_2 lid));
let (params, clty) =
Ctype.instance_class decl.clty_params decl.clty_type
in
let sty = Ctype.self_type clty in
if List.length params <> List.length styl then
raise(Error(scty.pcty_loc,
Parameter_arity_mismatch (lid, List.length params,
List.length styl)));
List.iter2
(fun sty ty ->
let ty' = transl_simple_type env false sty in
try Ctype.unify env ty' ty with Ctype.Unify trace ->
raise(Error(sty.ptyp_loc, Parameter_mismatch trace)))
styl params;
Tcty_constr (path, params, clty)
| Pcty_signature (sty, sign) ->
Tcty_signature (class_signature env sty sign)
| Pcty_fun (l, sty, scty) ->
let ty = transl_simple_type env false sty in
let cty = class_type env scty in
Tcty_fun (l, ty, cty)
(*******************************)
module StringSet = Set.Make(struct type t = string let compare = compare end)
let rec class_field cl_num self_type meths vars
(val_env, met_env, par_env, fields, concr_meths, inh_vals) =
function
Pcf_inher (sparent, super) ->
let parent = class_expr cl_num val_env par_env sparent in
let (cl_sig, concr_meths) =
inheritance true self_type val_env concr_meths sparent.pcl_loc
parent.cl_type
in
(* Variables *)
let (val_env, met_env, par_env, inh_vars, inh_vals) =
Vars.fold
(fun lab (mut, ty) (val_env, met_env, par_env, inh_vars, inh_vals) ->
let (id, val_env, met_env, par_env) =
enter_val cl_num vars lab mut ty val_env met_env par_env
in
if StringSet.mem lab inh_vals then
Location.print_warning sparent.pcl_loc
(Warnings.Hide_instance_variable lab);
(val_env, met_env, par_env, (lab, id) :: inh_vars,
StringSet.add lab inh_vals))
cl_sig.cty_vars (val_env, met_env, par_env, [], inh_vals)
in
(* Inherited concrete methods *)
let inh_meths =
Concr.fold (fun lab rem -> (lab, Ident.create lab)::rem)
cl_sig.cty_concr []
in
(* Super *)
let (val_env, met_env, par_env) =
match super with
None ->
(val_env, met_env, par_env)
| Some name ->
let (id, val_env, met_env, par_env) =
enter_met_env name (Val_anc (inh_meths, cl_num)) self_type
val_env met_env par_env
in
(val_env, met_env, par_env)
in
(val_env, met_env, par_env,
lazy(Cf_inher (parent, inh_vars, inh_meths))::fields,
concr_meths, inh_vals)
| Pcf_val (lab, mut, sexp, loc) ->
if StringSet.mem lab inh_vals then
Location.print_warning loc (Warnings.Hide_instance_variable lab);
let exp =
try type_exp val_env sexp with Ctype.Unify [(ty, _)] ->
raise(Error(loc, Make_nongen_seltype ty))
in
let (id, val_env, met_env, par_env) =
enter_val cl_num vars lab mut exp.exp_type val_env met_env par_env
in
(val_env, met_env, par_env, lazy(Cf_val (lab, id, exp)) :: fields,
concr_meths, inh_vals)
| Pcf_virt (lab, priv, sty, loc) ->
virtual_method val_env meths self_type lab priv sty loc;
(val_env, met_env, par_env, fields, concr_meths, inh_vals)
| Pcf_meth (lab, priv, expr, loc) ->
let meth_expr = make_method cl_num expr in
Ctype.raise_nongen_level ();
let (_, ty) =
Ctype.filter_self_method val_env lab priv meths self_type
in
let meth_type = Ctype.newvar () in
let (obj_ty, res_ty) = Ctype.filter_arrow val_env meth_type "" in
Ctype.unify val_env obj_ty self_type;
Ctype.unify val_env res_ty ty;
let ty' = type_approx met_env expr in
begin try Ctype.unify met_env ty' res_ty with Ctype.Unify trace ->
raise(Typecore.Error(expr.pexp_loc, Expr_type_clash(trace)))
end;
Ctype.end_def ();
let field =
lazy begin
Ctype.raise_nongen_level ();
let texp = type_expect met_env meth_expr meth_type in
Ctype.end_def ();
Cf_meth (lab, texp)
end in
(val_env, met_env, par_env, field::fields,
Concr.add lab concr_meths, inh_vals)
| Pcf_cstr (sty, sty', loc) ->
type_constraint val_env sty sty' loc;
(val_env, met_env, par_env, fields, concr_meths, inh_vals)
| Pcf_let (rec_flag, sdefs, loc) ->
let (defs, val_env) =
try
Typecore.type_let val_env rec_flag sdefs
with Ctype.Unify [(ty, _)] ->
raise(Error(loc, Make_nongen_seltype ty))
in
let (vals, met_env, par_env) =
List.fold_right
(fun id (vals, met_env, par_env) ->
let expr =
Typecore.type_exp val_env
{pexp_desc = Pexp_ident (Longident.Lident (Ident.name id));
pexp_loc = Location.none}
in
let desc =
{val_type = expr.exp_type;
val_kind = Val_ivar (Immutable, cl_num)}
in
let id' = Ident.create (Ident.name id) in
((id', expr)
:: vals,
Env.add_value id' desc met_env,
Env.add_value id' desc par_env))
(let_bound_idents defs)
([], met_env, par_env)
in
(val_env, met_env, par_env, lazy(Cf_let(rec_flag, defs, vals))::fields,
concr_meths, inh_vals)
| Pcf_init expr ->
let expr = make_method cl_num expr in
let field =
lazy begin
Ctype.raise_nongen_level ();
let meth_type = Ctype.newvar () in
let (obj_ty, res_ty) = Ctype.filter_arrow val_env meth_type "" in
Ctype.unify val_env obj_ty self_type;
Ctype.unify val_env res_ty (Ctype.instance Predef.type_unit);
let texp = type_expect met_env expr meth_type in
Ctype.end_def ();
Cf_init texp
end in
(val_env, met_env, par_env, field::fields, concr_meths, inh_vals)
and class_structure cl_num val_env met_env (spat, str) =
(* Environment for substructures *)
let par_env = met_env in
(* Self binder *)
let (pat, meths, vars, val_env, meth_env, par_env) =
type_self_pattern cl_num val_env met_env par_env spat
in
let self_type = pat.pat_type in
(* Check that the binder has a correct type, and introduce a dummy
method preventing self type from being closed. *)
let ty = Ctype.newvar () in
Ctype.unify val_env
(Ctype.filter_method val_env dummy_method Private ty)
(Ctype.newty (Ttuple []));
begin try Ctype.unify val_env self_type ty with
Ctype.Unify _ ->
raise(Error(pat.pat_loc, Pattern_type_clash self_type))
end;
(* Class fields *)
let (_, _, _, fields, concr_meths, _) =
List.fold_left (class_field cl_num self_type meths vars)
(val_env, meth_env, par_env, [], Concr.empty, StringSet.empty)
str
in
let fields = List.map Lazy.force (List.rev fields) in
{cl_field = fields;
cl_meths = Meths.map (function (id, ty) -> id) !meths},
{cty_self = self_type;
cty_vars = Vars.map (function (id, mut, ty) -> (mut, ty)) !vars;
cty_concr = concr_meths }
and class_expr cl_num val_env met_env scl =
match scl.pcl_desc with
Pcl_constr (lid, styl) ->
let (path, decl) =
try Env.lookup_class lid val_env with Not_found ->
raise(Error(scl.pcl_loc, Unbound_class lid))
in
if Path.same decl.cty_path unbound_class then
raise(Error(scl.pcl_loc, Unbound_class_2 lid));
let tyl = List.map (transl_simple_type val_env false) styl in
let (params, clty) =
Ctype.instance_class decl.cty_params decl.cty_type
in
let clty' = abbreviate_class_type path params clty in
if List.length params <> List.length styl then
raise(Error(scl.pcl_loc,
Parameter_arity_mismatch (lid, List.length params,
List.length styl)));
List.iter2
(fun sty ty ->
let ty' = transl_simple_type val_env false sty in
try Ctype.unify val_env ty' ty with Ctype.Unify trace ->
raise(Error(sty.ptyp_loc, Parameter_mismatch trace)))
styl params;
let cl =
{cl_desc = Tclass_ident path;
cl_loc = scl.pcl_loc;
cl_type = clty'}
in
let (vals, meths, concrs) = extract_constraints clty in
{cl_desc = Tclass_constraint (cl, vals, meths, concrs);
cl_loc = scl.pcl_loc;
cl_type = clty'}
| Pcl_structure cl_str ->
let (desc, ty) = class_structure cl_num val_env met_env cl_str in
{cl_desc = Tclass_structure desc;
cl_loc = scl.pcl_loc;
cl_type = Tcty_signature ty}
| Pcl_fun (l, Some default, spat, sbody) ->
let loc = default.pexp_loc in
let scases =
[{ppat_loc = loc; ppat_desc =
Ppat_construct(Longident.Lident"Some",
Some{ppat_loc = loc; ppat_desc = Ppat_var"*sth*"},
false)},
{pexp_loc = loc; pexp_desc = Pexp_ident(Longident.Lident"*sth*")};
{ppat_loc = loc; ppat_desc =
Ppat_construct(Longident.Lident"None", None, false)},
default] in
let smatch =
{pexp_loc = loc; pexp_desc =
Pexp_match({pexp_loc = loc; pexp_desc =
Pexp_ident(Longident.Lident"*opt*")},
scases)} in
let sfun =
{pcl_loc = scl.pcl_loc; pcl_desc =
Pcl_fun(l, None, {ppat_loc = loc; ppat_desc = Ppat_var"*opt*"},
{pcl_loc = scl.pcl_loc; pcl_desc =
Pcl_let(Default, [spat, smatch], sbody)})}
in
class_expr cl_num val_env met_env sfun
| Pcl_fun (l, _, spat, scl') ->
let (pat, pv, val_env, met_env) =
Typecore.type_class_arg_pattern cl_num val_env met_env l spat
in
let pv =
List.map
(function (id, id', ty) ->
(id,
Typecore.type_exp val_env
{pexp_desc = Pexp_ident (Longident.Lident (Ident.name id));
pexp_loc = Location.none}))
pv
in
let rec all_labeled = function
Tcty_fun ("", _, _) -> false
| Tcty_fun (l, _, ty_fun) -> l.[0] <> '?' && all_labeled ty_fun
| _ -> true
in
let partial =
Parmatch.check_partial val_env pat.pat_loc
[pat, (* Dummy expression *)
{exp_desc = Texp_constant (Asttypes.Const_int 1);
exp_loc = Location.none;
exp_type = Ctype.none;
exp_env = Env.empty }] in
Ctype.raise_nongen_level ();
let cl = class_expr cl_num val_env met_env scl' in
Ctype.end_def ();
if Btype.is_optional l && all_labeled cl.cl_type then
Location.print_warning pat.pat_loc
(Warnings.Other "This optional argument cannot be erased");
{cl_desc = Tclass_fun (pat, pv, cl, partial);
cl_loc = scl.pcl_loc;
cl_type = Tcty_fun (l, pat.pat_type, cl.cl_type)}
| Pcl_apply (scl', sargs) ->
let cl = class_expr cl_num val_env met_env scl' in
let rec type_args args omitted ty_fun sargs more_sargs =
match ty_fun with
| Tcty_fun (l, ty, ty_fun) when sargs <> [] || more_sargs <> [] ->
let name = Btype.label_name l in
let sargs, more_sargs, arg =
if !Clflags.classic && not (Btype.is_optional l) then begin
match sargs, more_sargs with
(l', sarg0)::_, _ ->
raise(Error(sarg0.pexp_loc, Apply_wrong_label(l')))
| _, (l', sarg0)::more_sargs ->
if l <> l' && l' <> "" then
raise(Error(sarg0.pexp_loc, Apply_wrong_label l'))
else ([], more_sargs, Some(type_argument val_env sarg0 ty))
| _ ->
assert false
end else try
let (l', sarg0, sargs, more_sargs) =
try
let (l', sarg0, sargs1, sargs2) =
Btype.extract_label name sargs
in (l', sarg0, sargs1 @ sargs2, more_sargs)
with Not_found ->
let (l', sarg0, sargs1, sargs2) =
Btype.extract_label name more_sargs
in (l', sarg0, sargs @ sargs1, sargs2)
in
sargs, more_sargs,
if Btype.is_optional l' || not (Btype.is_optional l) then
Some (type_argument val_env sarg0 ty)
else
let arg = type_argument val_env
sarg0 (extract_option_type val_env ty) in
Some (option_some arg)
with Not_found ->
sargs, more_sargs,
if Btype.is_optional l &&
(List.mem_assoc "" sargs || List.mem_assoc "" more_sargs)
then
Some (option_none ty Location.none)
else None
in
let omitted = if arg = None then (l,ty) :: omitted else omitted in
type_args (arg::args) omitted ty_fun sargs more_sargs
| _ ->
match sargs @ more_sargs with
(l, sarg0)::_ ->
if omitted <> [] then
raise(Error(sarg0.pexp_loc, Apply_wrong_label l))
else
raise(Error(cl.cl_loc, Cannot_apply cl.cl_type))
| [] ->
(List.rev args,
List.fold_left
(fun ty_fun (l,ty) -> Tcty_fun(l,ty,ty_fun))
ty_fun omitted)
in
let (args, cty) =
if !Clflags.classic then
type_args [] [] cl.cl_type [] sargs
else
type_args [] [] cl.cl_type sargs []
in
{cl_desc = Tclass_apply (cl, args);
cl_loc = scl.pcl_loc;
cl_type = cty}
| Pcl_let (rec_flag, sdefs, scl') ->
let (defs, val_env) =
try
Typecore.type_let val_env rec_flag sdefs
with Ctype.Unify [(ty, _)] ->
raise(Error(scl.pcl_loc, Make_nongen_seltype ty))
in
let (vals, met_env) =
List.fold_right
(fun id (vals, met_env) ->
Ctype.begin_def ();
let expr =
Typecore.type_exp val_env
{pexp_desc = Pexp_ident (Longident.Lident (Ident.name id));
pexp_loc = Location.none}
in
Ctype.end_def ();
Ctype.generalize expr.exp_type;
let desc =
{val_type = expr.exp_type; val_kind = Val_ivar (Immutable,
cl_num)}
in
let id' = Ident.create (Ident.name id) in
((id', expr)
:: vals,
Env.add_value id' desc met_env))
(let_bound_idents defs)
([], met_env)
in
let cl = class_expr cl_num val_env met_env scl' in
{cl_desc = Tclass_let (rec_flag, defs, vals, cl);
cl_loc = scl.pcl_loc;
cl_type = cl.cl_type}
| Pcl_constraint (scl', scty) ->
Ctype.begin_class_def ();
Typetexp.narrow ();
let cl = class_expr cl_num val_env met_env scl' in
Typetexp.widen ();
Typetexp.narrow ();
let clty = class_type val_env scty in
Typetexp.widen ();
Ctype.end_def ();
limited_generalize (Ctype.row_variable (Ctype.self_type cl.cl_type))
cl.cl_type;
limited_generalize (Ctype.row_variable (Ctype.self_type clty)) clty;
begin match Includeclass.class_types val_env cl.cl_type clty with
[] -> ()
| error -> raise(Error(cl.cl_loc, Class_match_failure error))
end;
let (vals, meths, concrs) = extract_constraints clty in
{cl_desc = Tclass_constraint (cl, vals, meths, concrs);
cl_loc = scl.pcl_loc;
cl_type = snd (Ctype.instance_class [] clty)}
(*******************************)
let temp_abbrev env id arity =
let params = ref [] in
for i = 1 to arity do
params := Ctype.newvar () :: !params
done;
let ty = Ctype.newobj (Ctype.newvar ()) in
let env =
Env.add_type id
{type_params = !params;
type_arity = arity;
type_kind = Type_abstract;
type_manifest = Some ty }
env
in
(!params, ty, env)
let rec initial_env define_class (res, env) (cl, id, ty_id, obj_id, cl_id) =
(* Temporary abbreviations *)
let arity = List.length (fst cl.pci_params) in
let (obj_params, obj_ty, env) = temp_abbrev env obj_id arity in
let (cl_params, cl_ty, env) = temp_abbrev env cl_id arity in
(* Temporary type for the class constructor *)
let constr_type = Ctype.newvar () in
let dummy_cty =
Tcty_signature
{ cty_self = Ctype.newvar ();
cty_vars = Vars.empty;
cty_concr = Concr.empty }
in
let dummy_class =
{cty_params = []; (* Dummy value *)
cty_type = dummy_cty; (* Dummy value *)
cty_path = unbound_class;
cty_new =
match cl.pci_virt with
Virtual -> None
| Concrete -> Some constr_type}
in
let env =
Env.add_cltype ty_id
{clty_params = []; (* Dummy value *)
clty_type = dummy_cty; (* Dummy value *)
clty_path = unbound_class} (
if define_class then
Env.add_class id dummy_class env
else
env)
in
((cl, id, ty_id,
obj_id, obj_params, obj_ty,
cl_id, cl_params, cl_ty,
constr_type, dummy_class)::res,
env)
let class_infos define_class kind
(cl, id, ty_id,
obj_id, obj_params, obj_ty,
cl_id, cl_params, cl_ty,
constr_type, dummy_class)
(res, env) =
reset_type_variables ();
Ctype.begin_class_def ();
(* Introduce class parameters *)
let params =
try
List.map (enter_type_variable true) (fst cl.pci_params)
with Already_bound ->
raise(Error(snd cl.pci_params, Repeated_parameter))
in
(* Type the class expression *)
let (expr, typ) = kind env cl.pci_expr in
Ctype.end_def ();
let sty = Ctype.self_type typ in
(* Generalize the row variable *)
let rv = Ctype.row_variable sty in
List.iter (Ctype.limited_generalize rv) params;
limited_generalize rv typ;
(* Check the abbreviation for the object type *)
let (obj_params', obj_type) = Ctype.instance_class params typ in
let constr = Ctype.newconstr (Path.Pident obj_id) obj_params in
begin
let ty = Ctype.self_type obj_type in
Ctype.hide_private_methods ty;
Ctype.close_object ty;
begin try
List.iter2 (Ctype.unify env) obj_params obj_params'
with Ctype.Unify _ ->
raise(Error(cl.pci_loc,
Bad_parameters (obj_id, constr,
Ctype.newconstr (Path.Pident obj_id)
obj_params')))
end;
begin try
Ctype.unify env ty constr
with Ctype.Unify _ ->
raise(Error(cl.pci_loc,
Abbrev_type_clash (constr, ty, Ctype.expand_head env constr)))
end
end;
(* Check the other temporary abbreviation (#-type) *)
begin
let (cl_params', cl_type) = Ctype.instance_class params typ in
let ty = Ctype.self_type cl_type in
Ctype.hide_private_methods ty;
Ctype.set_object_name obj_id (Ctype.row_variable ty) cl_params ty;
begin try
List.iter2 (Ctype.unify env) cl_params cl_params'
with Ctype.Unify _ ->
raise(Error(cl.pci_loc,
Bad_parameters (cl_id,
Ctype.newconstr (Path.Pident cl_id)
cl_params,
Ctype.newconstr (Path.Pident cl_id)
cl_params')))
end;
begin try
Ctype.unify env ty cl_ty
with Ctype.Unify _ ->
let constr = Ctype.newconstr (Path.Pident cl_id) params in
raise(Error(cl.pci_loc, Abbrev_type_clash (constr, ty, cl_ty)))
end
end;
(* Type of the class constructor *)
begin try
Ctype.unify env (constructor_type constr obj_type) constr_type
with Ctype.Unify trace ->
raise(Error(cl.pci_loc,
Constructor_type_mismatch (cl.pci_name, trace)))
end;
(* Class and class type temporary definitions *)
let cltydef =
{clty_params = params; clty_type = class_body typ;
clty_path = Path.Pident obj_id}
and clty =
{cty_params = params; cty_type = typ;
cty_path = Path.Pident obj_id;
cty_new =
match cl.pci_virt with
Virtual -> None
| Concrete -> Some constr_type}
in
dummy_class.cty_type <- typ;
let env =
Env.add_cltype ty_id cltydef (
if define_class then Env.add_class id clty env else env)
in
if cl.pci_virt = Concrete then begin
match virtual_methods typ with
[] -> ()
| mets -> raise(Error(cl.pci_loc, Virtual_class(define_class, mets)))
end;
(* Misc. *)
let arity = Ctype.class_type_arity typ in
let pub_meths =
let (fields, _) =
Ctype.flatten_fields (Ctype.object_fields (Ctype.expand_head env obj_ty))
in
List.map (function (lab, _, _) -> lab) fields
in
(* Final definitions *)
let (params', typ') = Ctype.instance_class params typ in
let cltydef =
{clty_params = params'; clty_type = class_body typ';
clty_path = Path.Pident obj_id}
and clty =
{cty_params = params'; cty_type = typ';
cty_path = Path.Pident obj_id;
cty_new =
match cl.pci_virt with
Virtual -> None
| Concrete -> Some constr_type}
in
let obj_abbr =
{type_params = obj_params;
type_arity = List.length obj_params;
type_kind = Type_abstract;
type_manifest = Some obj_ty }
in
let (cl_params, cl_ty) =
Ctype.instance_parameterized_type params (Ctype.self_type typ)
in
Ctype.hide_private_methods cl_ty;
Ctype.set_object_name obj_id (Ctype.row_variable cl_ty) cl_params cl_ty;
let cl_abbr =
{type_params = cl_params;
type_arity = List.length cl_params;
type_kind = Type_abstract;
type_manifest = Some cl_ty }
in
((cl, id, clty, ty_id, cltydef, obj_id, obj_abbr, cl_id, cl_abbr,
arity, pub_meths, expr) :: res,
env)
let final_env define_class
(cl, id, clty, ty_id, cltydef, obj_id, obj_abbr, cl_id, cl_abbr,
arity, pub_meths, expr)
(res, env) =
List.iter Ctype.generalize clty.cty_params;
generalize_class_type clty.cty_type;
begin match clty.cty_new with
None -> ()
| Some ty -> Ctype.generalize ty
end;
List.iter Ctype.generalize obj_abbr.type_params;
begin match obj_abbr.type_manifest with
None -> ()
| Some ty -> Ctype.generalize ty
end;
List.iter Ctype.generalize cl_abbr.type_params;
begin match cl_abbr.type_manifest with
None -> ()
| Some ty -> Ctype.generalize ty
end;
if not (closed_class clty) then
raise(Error(cl.pci_loc, Non_generalizable_class (id, clty)));
begin match
Ctype.closed_class clty.cty_params
(Ctype.signature_of_class_type clty.cty_type)
with
None -> ()
| Some reason ->
let printer =
if define_class then fun () -> Printtyp.class_declaration id clty
else fun () -> Printtyp.cltype_declaration id cltydef
in
raise(Error(cl.pci_loc, Unbound_type_var(printer, reason)))
end;
let env =
Env.add_type obj_id obj_abbr (
Env.add_type cl_id cl_abbr (
Env.add_cltype ty_id cltydef (
if define_class then Env.add_class id clty env else env)))
in
((id, clty, ty_id, cltydef, obj_id, obj_abbr, cl_id, cl_abbr,
arity, pub_meths, expr)::res,
env)
(*******************************)
let type_classes define_class kind env cls =
let cls =
List.map
(function cl ->
(cl,
Ident.create cl.pci_name, Ident.create cl.pci_name,
Ident.create cl.pci_name, Ident.create ("#" ^ cl.pci_name)))
cls
in
Ctype.init_def (Ident.current_time ());
Ctype.begin_class_def ();
let (res, env) =
List.fold_left (initial_env define_class) ([], env) cls
in
let (res, env) =
List.fold_right (class_infos define_class kind) res ([], env)
in
Ctype.end_def ();
let (res, env) =
List.fold_right (final_env define_class) res ([], env)
in
(List.rev res, env)
let class_num = ref 0
let class_declaration env sexpr =
incr class_num;
let expr = class_expr (string_of_int !class_num) env env sexpr in
(expr, expr.cl_type)
let class_description env sexpr =
let expr = class_type env sexpr in
(expr, expr)
let class_declarations env cls =
type_classes true class_declaration env cls
let class_descriptions env cls =
type_classes true class_description env cls
let class_type_declarations env cls =
let (decl, env) =
type_classes false class_description env cls
in
(List.map
(function
(_, _, ty_id, cltydef, obj_id, obj_abbr, cl_id, cl_abbr, _, _, _) ->
(ty_id, cltydef, obj_id, obj_abbr, cl_id, cl_abbr))
decl,
env)
(*******************************)
(* Error report *)
open Formatmsg
let report_error = function
| Repeated_parameter ->
print_string "A type parameter occurs several times"
| Unconsistent_constraint trace ->
Printtyp.unification_error true trace
(function () ->
print_string "The class constraints are not consistent : type")
(function () ->
print_string "is not compatible with type")
| Method_type_mismatch (m, trace) ->
Printtyp.unification_error true trace
(function () ->
print_string "The method ";
print_string m; print_space ();
print_string "has type")
(function () ->
print_string "but is expected to have type")
| Structure_expected clty ->
open_box 0;
print_string
"This class expression is not a class structure; it has type";
print_space();
Printtyp.class_type clty;
close_box()
| Cannot_apply clty ->
print_string
"This class expression is not a class function, it cannot be applied"
| Apply_wrong_label l ->
if l = "" then
print_string "This argument cannot be applied without label"
else
printf "This argument cannot be applied with label %s:" l
| Pattern_type_clash ty ->
(* XXX Trace *)
(* XXX Revoir message d'erreur *)
open_box 0;
print_string "This pattern cannot match self: \
it only matches values of type";
print_space ();
Printtyp.type_expr ty;
close_box ()
| Unbound_class cl ->
print_string "Unbound class"; print_space ();
Printtyp.longident cl
| Unbound_class_2 cl ->
print_string "The class"; print_space ();
Printtyp.longident cl; print_space ();
print_string "is not yet completely defined"
| Unbound_class_type cl ->
print_string "Unbound class type"; print_space ();
Printtyp.longident cl
| Unbound_class_type_2 cl ->
print_string "The class type"; print_space ();
Printtyp.longident cl; print_space ();
print_string "is not yet completely defined"
| Abbrev_type_clash (abbrev, actual, expected) ->
(* XXX Afficher une trace ? *)
open_box 0;
Printtyp.reset ();
Printtyp.mark_loops abbrev; Printtyp.mark_loops actual;
Printtyp.mark_loops expected;
print_string "The abbreviation"; print_space ();
Printtyp.type_expr abbrev; print_space ();
print_string "expands to type"; print_space ();
Printtyp.type_expr actual; print_space ();
print_string "but is used with type"; print_space ();
Printtyp.type_expr expected;
close_box ()
| Constructor_type_mismatch (c, trace) ->
Printtyp.unification_error true trace
(function () ->
print_string "The expression \"new ";
print_string c;
print_string "\" has type")
(function () ->
print_string "but is used with type")
| Virtual_class (cl, mets) ->
open_vbox 0;
if cl then
print_string "This class should be virtual"
else
print_string "This class type should be virtual";
print_space ();
open_box 2;
print_string "The following methods are undefined :";
List.iter
(function met ->
print_space (); print_string met)
mets;
close_box (); close_box()
| Parameter_arity_mismatch(lid, expected, provided) ->
open_box 0;
print_string "The class constructor "; Printtyp.longident lid;
print_space(); print_string "expects "; print_int expected;
print_string " type argument(s),"; print_space();
print_string "but is here applied to "; print_int provided;
print_string " type argument(s)";
close_box()
| Parameter_mismatch trace ->
Printtyp.unification_error true trace
(function () ->
print_string "The type parameter")
(function () ->
print_string "does not meet its constraint: it should be")
| Bad_parameters (id, params, cstrs) ->
open_box 0;
Printtyp.reset ();
Printtyp.mark_loops params; Printtyp.mark_loops cstrs;
print_string "The abbreviation"; print_space ();
Printtyp.ident id; print_space ();
print_string "is used with parameters"; print_space ();
Printtyp.type_expr params; print_space ();
print_string "wich are incompatible with constraints"; print_space ();
Printtyp.type_expr cstrs; print_space ();
close_box ()
| Class_match_failure error ->
Includeclass.report_error error
| Unbound_val lab ->
print_string "Unbound instance variable "; print_string lab
| Unbound_type_var (printer, reason) ->
Printtyp.reset ();
open_vbox 0;
open_box 0;
print_string "Some type variables are unbound in this type:";
print_break 1 2;
printer ();
close_box ();
print_space ();
open_box 0;
begin match reason with
Ctype.CC_Method (ty0, real, lab, ty) ->
Printtyp.reset ();
Printtyp.mark_loops ty; Printtyp.mark_loops ty0;
print_string "The method"; print_space ();
print_string lab; print_space ();
print_string "has type"; print_break 1 2;
Printtyp.type_expr ty; print_space ();
print_string "where"; print_space ();
if real then begin
Printtyp.type_expr ty0; print_space ()
end else begin
print_string ".."; print_space ()
end;
print_string "is unbound"
| Ctype.CC_Value (ty0, real, lab, ty) ->
Printtyp.reset ();
Printtyp.mark_loops ty; Printtyp.mark_loops ty0;
print_string "The instance variable"; print_space ();
print_string lab; print_space ();
print_string "has type"; print_break 1 2;
Printtyp.type_expr ty; print_space ();
print_string "where"; print_space ();
if real then begin
Printtyp.type_expr ty0; print_space ()
end else begin
print_string ".."; print_space ()
end;
print_string "is unbound"
end;
close_box ();
close_box ()
| Make_nongen_seltype ty ->
open_vbox 0;
open_box 0;
print_string "Self type should not occur in the non-generic type";
print_break 1 2;
Printtyp.type_scheme ty;
close_box ();
print_cut ();
print_string "It would escape the scope of its class";
close_box ()
| Non_generalizable_class (id, clty) ->
open_box 0;
print_string "The type of this class,"; print_space();
Printtyp.class_declaration id clty; print_string ","; print_space();
print_string "contains type variables that cannot be generalized";
close_box()