ocaml/typing/typeclass.ml

1241 lines
41 KiB
OCaml

(***********************************************************************)
(* *)
(* Objective Caml *)
(* *)
(* Jerome Vouillon, projet Cristal, INRIA Rocquencourt *)
(* *)
(* Copyright 1996 Institut National de Recherche en Informatique et *)
(* Automatique. Distributed only by permission. *)
(* *)
(***********************************************************************)
(* $Id$ *)
open Misc
open Parsetree
open Asttypes
open Types
open Typedtree
open Typecore
open Typetexp
type error =
Duplicate_method of string
| Duplicate_variable of string
| Duplicate_super_variable of string
| Repeated_parameter
| Virtual_class of string * string
| Closed_class of string
| Closed_ancestor of string * Path.t * string
| Non_generalizable of Ident.t * type_expr list
| Non_closed of Ident.t * type_expr list * type_expr *
Ctype.closed_schema_result
| Mutable_var of string
| Undefined_var of string
| Variable_type_mismatch of string * (type_expr * type_expr) list
| Method_type_mismatch of string * (type_expr * type_expr) list
| Unconsistent_constraint
| Unbound_class of Longident.t
| Argument_type_mismatch of (type_expr * type_expr) list
| Abbrev_type_clash of type_expr * type_expr * type_expr
| Bad_parameters of Ident.t * type_expr * type_expr
| Illdefined_class of string
| Argument_arity_mismatch of Path.t * int * int
| Parameter_arity_mismatch of Path.t * int * int
| Parameter_mismatch of (type_expr * type_expr) list
exception Error of Location.t * error
(*****************)
(* Common code *)
(*****************)
let rec iter f env =
function
[] ->
([], env)
| cl :: cl_rem ->
let (cl', env') = f env cl in
let (cl_rem', env'') = iter f env' cl_rem in
(cl'::cl_rem', env'')
let check_mutable loc lab mut mut' =
match mut, mut' with
(Immutable, Mutable) ->
raise(Error(loc, Mutable_var lab))
| _ ->
()
let rec add_methods env self t =
match (Ctype.repr t).desc with
Tfield (lab, k, _, t') ->
if Btype.field_kind_repr k = Fpresent then begin
Ctype.filter_method env lab Public self; ()
end;
add_methods env self t'
| _ ->
()
(* Make sure that [self] has at least the methods of [obj]. *)
let equalize_methods env self obj =
match (Ctype.expand_head env obj).desc with
Tobject (ty, _) ->
let rec equalize_methods_rec t =
match (Ctype.repr t).desc with
Tfield (lab, k, _, t') ->
if Btype.field_kind_repr k = Fpresent then begin
Ctype.filter_method env lab Public self; ()
end;
equalize_methods_rec t'
| _ ->
()
in
equalize_methods_rec ty
| _ ->
fatal_error "Typeclass.equalize_methods"
let rec type_meth env loc self ty =
match (Ctype.repr ty).desc with
Tfield (lab, k, ty, ty') ->
if Btype.field_kind_repr k = Fpresent then begin
let ty0 = Ctype.filter_method env lab Public self in
begin try
Ctype.unify env ty ty0
with Ctype.Unify trace ->
raise(Error(loc, Method_type_mismatch (lab, trace)))
end
end;
type_meth env loc self ty'
| _ ->
()
let vals_remove lab vals =
Vars.fold (fun l k v -> if lab = l then v else Vars.add l k v)
vals Vars.empty
let insert_value env lab priv mut ty loc vals =
begin try
let (mut', ty') = Vars.find lab vals in
check_mutable loc lab mut mut';
try Ctype.unify env ty ty' with Ctype.Unify trace ->
raise(Error(loc, Variable_type_mismatch(lab, trace)))
with Not_found -> () end;
if priv = Private then
vals_remove lab vals
else
Vars.add lab (mut, ty) vals
let rec closed_scheme t =
match (Ctype.repr t).desc with
Tfield (lab, k, _, t') when Btype.field_kind_repr k = Fpresent ->
Ctype.newty (Tfield (lab, Fpresent, Ctype.newvar (), closed_scheme t'))
| Tfield (lab, _, _, t') ->
closed_scheme t'
| Tnil ->
Ctype.newty Tnil
| _ ->
fatal_error "Typeclass.closed_scheme"
let change_value_status lab priv mut loc vals =
try
let (mut', ty') = Vars.find lab vals in
check_mutable loc lab mut mut';
if priv = Private then
(vals_remove lab vals, ty')
else
(Vars.add lab (mut, ty') vals, ty')
with Not_found ->
raise(Error(loc, Undefined_var lab))
let missing_method env ty ty' =
let rec missing_method_rec met=
match (Ctype.repr met).desc with
Tfield(lab, k, _, met') ->
begin try
if Btype.field_kind_repr k = Fpresent then begin
Ctype.filter_method env lab Public ty; ()
end;
missing_method_rec met'
with Ctype.Unify _ ->
lab
end
| _ ->
fatal_error "Typeclass.missing_method (1)"
in
match (Ctype.expand_head env ty').desc with
Tobject (met, _) ->
missing_method_rec met
| _ ->
fatal_error "Typeclass.missing_method (2)"
let generalize_class cl_sig =
List.iter Ctype.generalize cl_sig.cty_params;
List.iter Ctype.generalize cl_sig.cty_args;
Vars.iter (fun l (m, t) -> Ctype.generalize t) cl_sig.cty_vars;
Meths.iter (fun l t -> Ctype.generalize t) cl_sig.cty_meths;
Ctype.generalize cl_sig.cty_self;
match cl_sig.cty_new with Some ty -> Ctype.generalize ty | None -> ()
(***********************)
(* Class translation *)
(***********************)
let make_stub env (cl, obj_id, cl_id) =
Ctype.begin_def ();
(* Create self (class type) *)
let self = Ctype.newobj (Ctype.newvar ()) in
(* Find concrete methods and marks methods *)
let concr_meths =
List.fold_left
(function meths ->
function
Pcf_inher (nm, _, _, _, loc) ->
let (_, anc) =
try
Env.lookup_class nm env
with Not_found ->
raise(Error(loc, Unbound_class nm))
in
begin match (Ctype.expand_head env anc.cty_self).desc with
Tobject (ty, _) ->
add_methods env self ty;
Concr.union anc.cty_concr meths
| _ -> fatal_error "Typeclass.make_stub"
end
| Pcf_val _ ->
meths
| Pcf_virt (lab, priv, _, _) ->
Ctype.filter_method env lab priv self;
meths
| Pcf_meth (lab, priv, _, _) ->
Ctype.filter_method env lab priv self;
Concr.add lab meths)
Concr.empty cl.pcl_field
in
Ctype.end_def ();
Ctype.generalize self;
(* Temporary object type *)
let temp_obj_params =
List.map (fun _ -> Ctype.newvar ()) (fst cl.pcl_param)
in
let temp_obj = Ctype.instance self in
let obj_temp_abbrev =
{ type_params = temp_obj_params;
type_arity = List.length temp_obj_params;
type_kind = Type_abstract;
type_manifest = Some temp_obj }
in let temp_env = Env.add_type obj_id obj_temp_abbrev env
in let abbrev =
Ctype.newty (Tconstr (Path.Pident obj_id, temp_obj_params, ref Mnil))
in
(* Temporary class type *)
let (temp_cl_params, temp_cl) =
if cl.pcl_closed = Closed then
(temp_obj_params,
Ctype.newty (Tconstr(Path.Pident obj_id, temp_obj_params, ref Mnil)))
else begin
let params = List.map (fun _ -> Ctype.newvar ()) (fst cl.pcl_param) in
let ty = Ctype.instance self in
Ctype.set_object_name ty params obj_id;
(params, ty)
end
in
let cl_temp_abbrev =
{ type_params = temp_cl_params;
type_arity = List.length temp_cl_params;
type_kind = Type_abstract;
type_manifest = Some temp_cl }
in let temp_env = Env.add_type cl_id cl_temp_abbrev temp_env
in let cl_abbrev =
Ctype.newty (Tconstr (Path.Pident cl_id, temp_cl_params, ref Mnil))
in
(* Temporary type for new *)
let new_args = List.map (fun _ -> Ctype.newvar ()) cl.pcl_args in
let new_ty =
if cl.pcl_kind = Concrete then
Some (List.fold_right
(fun arg ty -> Ctype.newty (Tarrow(arg, ty)))
new_args abbrev)
else
None
in let cl_temp_sig =
{ cty_params = [];
cty_args = []; cty_vars = Vars.empty;
cty_meths = Meths.empty;
cty_self = self; cty_concr = concr_meths;
cty_new = new_ty }
in let (id, temp_env) = Env.enter_class cl.pcl_name cl_temp_sig temp_env in
((cl, id, cl_id, obj_id, self, concr_meths, new_args, new_ty,
temp_cl, temp_cl_params, cl_abbrev, temp_obj, temp_obj_params, abbrev),
temp_env)
let type_class_field env var_env self cl
(met_env, fields, vars_sig, meths) =
function
Pcf_inher (cl_name, params, args, super, loc) ->
(* Find class type *)
let (path, cl_type) =
try
Env.lookup_class cl_name env
with Not_found ->
raise(Error(loc, Unbound_class cl_name))
in
let (params', args', vars', meths', self') =
Ctype.instance_class cl_type
in
(* Unify parameters *)
if List.length params <> List.length params' then
raise(Error(loc, Parameter_arity_mismatch
(path, List.length params', List.length params)));
List.iter2
(fun sty ty ->
let ty' = Typetexp.transl_simple_type var_env false sty in
try Ctype.unify var_env ty' ty with Ctype.Unify trace ->
raise(Error(sty.ptyp_loc, Parameter_mismatch trace)))
params params';
(* Type arguments *)
if List.length args <> List.length args' then
raise(Error(loc, Argument_arity_mismatch
(path, List.length args', List.length args)));
let args = List.map2 (type_expect var_env) args args' in
(* Variables *)
let (vars, vars_sig, met_env) =
Vars.fold
(fun lab (mut, ty) (l, v_sig, env) ->
let (id, env) =
Env.enter_value lab
{val_type = ty; val_kind = Val_ivar mut} env
in
((lab, id)::l,
insert_value var_env lab Public mut ty loc v_sig,
env))
vars' ([], vars_sig, met_env)
in
(* Methods *)
let meths =
Meths.fold
(fun lab ty m ->
let (id, ty') =
try Meths.find lab m with Not_found ->
(Ident.create lab,
Ctype.filter_method var_env lab Private self)
in
begin try Ctype.unify env ty ty' with Ctype.Unify trace ->
raise(Error(loc, Method_type_mismatch (lab, trace)))
end;
Meths.add lab (id, ty) m)
meths' meths
in
(* Self type *)
let ty' = Ctype.expand_head var_env self' in
begin match ty'.desc with
Tobject (fi, _) ->
if not (Ctype.opened_object ty') then
begin try
Ctype.unify var_env self (Ctype.newobj (closed_scheme fi))
with Ctype.Unify _ ->
let lab = missing_method var_env ty' self in
raise(Error(loc, Closed_ancestor (cl.pcl_name, path, lab)))
end;
Ctype.unify var_env ty' self;
type_meth var_env loc self fi
| _ ->
fatal_error "Typeclass.transl_class"
end;
(* Super methods *)
let (met, met_env) =
match super with
None ->
([], met_env)
| Some name ->
let ty = Ctype.newobj (Ctype.newvar ()) in
let used_methods =
Concr.fold
(fun lab rem ->
Ctype.unify met_env
(Ctype.filter_method met_env lab Public ty)
(Ctype.filter_method met_env lab Public self);
(lab, Ident.create lab)::rem)
cl_type.cty_concr
[]
in
Ctype.close_object ty;
let (id, met_env) =
Env.enter_value name
{val_type = ty; val_kind = Val_anc used_methods} met_env
in
(used_methods, met_env)
in
let met' = Meths.fold (fun lab _ rem -> lab::rem) cl_type.cty_meths [] in
(met_env, Cf_inher (path, args, vars, met, met')::fields,
vars_sig, meths)
| Pcf_val (lab, priv, mut, sinit, loc) ->
begin match sinit with
Some sexp ->
let exp = type_exp var_env sexp in
let (id, met_env) =
Env.enter_value lab
{val_type = exp.exp_type; val_kind = Val_ivar mut} met_env
in
(met_env, Cf_val (lab, id, priv, Some exp)::fields,
insert_value var_env lab priv mut exp.exp_type loc vars_sig,
meths)
| None ->
let (vars_sig, ty) =
change_value_status lab priv mut loc vars_sig
in
let (id, met_env) =
Env.enter_value lab
{val_type = ty; val_kind = Val_ivar mut} met_env
in
(met_env, Cf_val (lab, id, priv, None)::fields, vars_sig, meths)
end
| Pcf_virt (lab, priv, ty, loc) ->
let ty = transl_simple_type met_env false ty in
let ty'' = Ctype.filter_method var_env lab priv self in
let (id, ty') =
try Meths.find lab meths with Not_found -> (Ident.create lab, ty'')
in
begin try Ctype.unify var_env ty ty'' with Ctype.Unify trace ->
raise(Error(loc, Method_type_mismatch (lab, trace)))
end;
(met_env, fields, vars_sig, Meths.add lab (id, ty) meths)
| Pcf_meth (lab, priv, expr, loc) ->
let ty' = Ctype.filter_method var_env lab priv self in
let (id, ty) =
try Meths.find lab meths with Not_found -> (Ident.create lab, ty')
in
let meths = Meths.add lab (id, ty) meths in
let (texp, meths) = type_method met_env self cl.pcl_self meths expr ty in
(met_env, Cf_meth (lab, texp)::fields, vars_sig, meths)
let transl_class temp_env env
(cl, id, cl_id, obj_id, self, concr_meths, new_args, new_ty,
temp_cl, temp_cl_params, cl_abbrev, temp_obj, temp_obj_params, abbrev)
=
reset_type_variables ();
Ctype.begin_def ();
(* Self type *)
let self = Ctype.instance self in
(* Introduce parameters *)
let params =
try
List.map (enter_type_variable true) (fst cl.pcl_param)
with Already_bound ->
raise(Error(snd cl.pcl_param, Repeated_parameter))
in
(* Translate constrained parameters *)
let cstr_params =
List.map (function (v, _, loc) -> type_variable loc v) cl.pcl_cstr
in
(* Bind self type variable *)
begin match cl.pcl_self_ty with
Some v -> Ctype.unify temp_env self (enter_type_variable false v)
| None -> ()
end;
(* Add constraints *)
List.iter2
(fun (v, sty, loc) ty' ->
try
Ctype.unify temp_env (transl_simple_type temp_env false sty) ty'
with Ctype.Unify _ ->
raise(Error(loc, Unconsistent_constraint)))
cl.pcl_cstr cstr_params;
(* Type arguments and fields *)
let (args, var_env) = type_pattern_list temp_env cl.pcl_args in
let arg_sig = List.map (fun exp -> exp.pat_type) args in
let (_, fields, vars_sig, meths) =
List.fold_left (type_class_field env var_env self cl)
(temp_env, [], Vars.empty, Meths.empty)
cl.pcl_field
in
(* Closeness of self (1) *)
if cl.pcl_closed = Closed then
Ctype.close_object self;
(* Generalize class *)
Ctype.end_def ();
List.iter Ctype.generalize params;
List.iter Ctype.generalize arg_sig;
Vars.iter (fun l (m, t) -> Ctype.generalize t) vars_sig;
Meths.iter (fun l (i, t) -> Ctype.generalize t) meths;
Ctype.generalize self;
(* Temporary class abbreviation *)
let (cl_params, cl_ty) = Ctype.instance_parameterized_type params self in
begin try Ctype.unify temp_env temp_cl cl_ty with Ctype.Unify _ ->
Ctype.remove_object_name temp_cl;
raise(Error(cl.pcl_loc, Abbrev_type_clash (cl_abbrev, cl_ty, temp_cl)))
end;
begin try
List.iter2 (Ctype.unify temp_env) temp_cl_params cl_params
with Ctype.Unify _ ->
raise(Error(cl.pcl_loc,
Bad_parameters (cl_id, cl_abbrev,
Ctype.newty (Tconstr (Path.Pident cl_id, cl_params,
ref Mnil)))))
end;
(* Object abbreviation and arguments for new *)
let (obj_params, arg_sig', obj_ty) =
Ctype.instance_parameterized_type_2 params arg_sig self
in
begin try Ctype.unify temp_env abbrev obj_ty with Ctype.Unify _ ->
raise(Error(cl.pcl_loc, Abbrev_type_clash (abbrev, obj_ty, temp_obj)))
end;
begin try
List.iter2 (Ctype.unify temp_env) temp_obj_params obj_params
with Ctype.Unify _ ->
raise(Error(cl.pcl_loc,
Bad_parameters (obj_id, abbrev,
Ctype.newty (Tconstr (Path.Pident obj_id, obj_params,
ref Mnil)))))
end;
Ctype.close_object temp_obj;
List.iter2
(fun ty (exp, ty') ->
begin try
Ctype.unify temp_env ty' ty
with Ctype.Unify trace ->
raise(Error(exp.pat_loc, Argument_type_mismatch trace))
end)
new_args (List.combine args arg_sig');
(* Fill interface / implementation *)
let cl_imp =
{ cl_args = args;
cl_field = List.rev fields;
cl_pub_meths = [];
cl_meths = Meths.map (function (id, ty) -> id) meths;
cl_loc = cl.pcl_loc }
in let cl_sig =
{ cty_params = params;
cty_args = arg_sig;
cty_vars = vars_sig;
cty_meths = Meths.map (function (id, ty) -> ty) meths;
cty_self = self;
cty_concr = concr_meths;
cty_new = new_ty }
in let new_env = Env.add_class id cl_sig env in
((cl, id, cl_id, obj_id, cl_sig, cl_imp, temp_obj,
temp_obj_params),
new_env)
let build_new_type temp_env env
(cl, id, cl_id, obj_id, cl_sig, cl_imp, temp_obj,
temp_obj_params)
=
(* Modify constrainsts to ensure the object abbreviation is well-formed *)
let (params, args, vars, meths, self) = Ctype.instance_class cl_sig in
List.iter2 (Ctype.unify temp_env) params temp_obj_params;
(* Never fails *)
(* Hide private methods *)
Ctype.hide_private_methods cl_sig.cty_self;
(* Closeness of self (2) *)
if (cl.pcl_closed <> Closed) & not (Ctype.opened_object self) then
raise(Error(cl.pcl_loc, Closed_class cl.pcl_name));
equalize_methods temp_env self temp_obj;
(* self should not be an abbreviation (printtyp) *)
let exp_self = Ctype.expand_head temp_env self in
let public_methods =
match (Ctype.repr exp_self).desc with
Tobject (fi, _) ->
let (meths, _) = Ctype.flatten_fields fi in
List.map (function (lab, _, _) -> lab) meths
| _ -> fatal_error "Typeclass.build_new_type"
in
(* Check whether the class can be concrete *)
if cl.pcl_kind = Concrete then
List.iter
(function m ->
if not (Concr.mem m cl_sig.cty_concr) then
raise(Error(cl.pcl_loc, Virtual_class (cl.pcl_name, m))))
public_methods;
(* Final class implementation and interface *)
let cl_imp =
{ cl_args = cl_imp.cl_args;
cl_field = cl_imp.cl_field;
cl_pub_meths = public_methods;
cl_meths = cl_imp.cl_meths;
cl_loc = cl_imp.cl_loc }
in
let cl_sig =
{ cty_params = params;
cty_args = args;
cty_vars = vars;
cty_meths = meths;
cty_self = exp_self;
cty_concr = cl_sig.cty_concr;
cty_new = cl_sig.cty_new } (* new is still monomorphic *)
in let new_env = Env.add_class id cl_sig env in
((cl, id, cl_id, obj_id, cl_sig, cl_imp), new_env)
let make_abbrev env
(cl, id, cl_id, obj_id, cl_sig, cl_imp)
=
(* Class type abbreviation *)
let cl_abbrev =
(* Make a fully generic copy *)
Subst.type_declaration Subst.identity
{ type_params = cl_sig.cty_params;
type_arity = List.length cl_sig.cty_params;
type_kind = Type_abstract;
type_manifest = Some
(if cl.pcl_closed = Closed then
Ctype.newgenty (Tconstr(Path.Pident obj_id, cl_sig.cty_params,
ref Mnil))
else begin
Ctype.set_object_name cl_sig.cty_self cl_sig.cty_params obj_id;
cl_sig.cty_self
end) }
in let new_env = Env.add_type cl_id cl_abbrev env in
(* Object type abbreviation *)
Ctype.begin_def ();
let (obj_ty_params, obj_ty) =
Ctype.instance_parameterized_type cl_sig.cty_params cl_sig.cty_self
in
Ctype.close_object obj_ty;
Ctype.end_def ();
List.iter Ctype.generalize obj_ty_params;
if not (List.for_all Ctype.closed_schema obj_ty_params) then
raise(Error(cl.pcl_loc,
Non_generalizable(obj_id, obj_ty_params)));
begin match Ctype.closed_schema_verbose obj_ty with
None -> ()
| Some v ->
raise(Error(cl.pcl_loc,
Non_closed(obj_id, obj_ty_params, obj_ty, v)))
end;
Ctype.generalize obj_ty;
let obj_abbrev =
(* Make a fully generic copy *)
Subst.type_declaration Subst.identity
{ type_params = obj_ty_params;
type_arity = List.length obj_ty_params;
type_kind = Type_abstract;
type_manifest =
Some (Ctype.unroll_abbrev obj_id obj_ty_params obj_ty) }
in let new_env = Env.add_type obj_id obj_abbrev new_env in
((id, cl_sig, cl_id, cl_abbrev, obj_id, obj_abbrev, cl_imp), new_env)
let transl_classes env cl =
let info =
List.map
(function cl ->
(cl, Ident.create cl.pcl_name, Ident.create ("#" ^ cl.pcl_name)))
cl
in
Ctype.init_def (Ident.current_time());
Ctype.begin_def ();
let (info, temp_env) = iter make_stub env info in
let (info, _) = iter (transl_class temp_env) env info in
let (info, new_env) = iter (build_new_type temp_env) env info in
Ctype.end_def ();
List.iter (fun (_, _, _, _, cl_sig, _) -> generalize_class cl_sig) info;
let (info, new_env) = iter make_abbrev new_env info in
(info, new_env)
(****************************)
(* Class type translation *)
(****************************)
let make_stub env (cl, obj_id, cl_id) =
Ctype.begin_def ();
(* Create self (class type) *)
let self = Ctype.newobj (Ctype.newvar ()) in
(* Find concrete methods and marks methods *)
let concr_meths =
List.fold_left
(function meths ->
function
Pctf_inher (nm, _, loc) ->
let (_, anc) =
try
Env.lookup_class nm env
with Not_found ->
raise(Error(loc, Unbound_class nm))
in
begin match (Ctype.expand_head env anc.cty_self).desc with
Tobject (ty, _) ->
add_methods env self ty;
Concr.union anc.cty_concr meths
| _ -> fatal_error "Typeclass.make_stub (type)"
end
| Pctf_val _ ->
meths
| Pctf_virt (lab, priv, _, _) ->
Ctype.filter_method env lab priv self;
meths
| Pctf_meth (lab, priv, _, _) ->
Ctype.filter_method env lab priv self;
Concr.add lab meths)
Concr.empty cl.pcty_field
in
Ctype.end_def ();
Ctype.generalize self;
(* Temporary object type *)
let temp_obj_params =
List.map (fun _ -> Ctype.newvar ()) (fst cl.pcty_param)
in
let temp_obj = Ctype.instance self in
let obj_temp_abbrev =
{ type_params = temp_obj_params;
type_arity = List.length temp_obj_params;
type_kind = Type_abstract;
type_manifest = Some temp_obj }
in
let temp_env = Env.add_type obj_id obj_temp_abbrev env in
let abbrev =
Ctype.newty (Tconstr (Path.Pident obj_id, temp_obj_params, ref Mnil))
in
(* Temporary class type *)
let (temp_cl_params, temp_cl) =
if cl.pcty_closed = Closed then
(temp_obj_params,
Ctype.newty (Tconstr(Path.Pident obj_id, temp_obj_params, ref Mnil)))
else begin
let params = List.map (fun _ -> Ctype.newvar ()) (fst cl.pcty_param) in
let ty = Ctype.instance self in
Ctype.set_object_name ty params obj_id;
(params, ty)
end
in
let cl_temp_abbrev =
{ type_params = temp_cl_params;
type_arity = List.length temp_cl_params;
type_kind = Type_abstract;
type_manifest = Some temp_cl }
in let temp_env = Env.add_type cl_id cl_temp_abbrev temp_env
in let cl_abbrev =
Ctype.newty (Tconstr (Path.Pident cl_id, temp_cl_params, ref Mnil))
in
(* Temporary class type *)
let cl_temp_sig =
{ cty_params = [];
cty_args = []; cty_vars = Vars.empty; cty_meths = Meths.empty;
cty_self = self; cty_concr = concr_meths;
cty_new = None }
in
let (id, temp_env) = Env.enter_class cl.pcty_name cl_temp_sig temp_env in
((cl, id, cl_id, obj_id, self, concr_meths, temp_cl,
temp_cl_params, cl_abbrev, temp_obj, temp_obj_params, abbrev),
temp_env)
let type_class_field env var_env self cl (vars_sig, meths_sig) =
function
Pctf_inher (cl_name, params, loc) ->
(* Find class type *)
let (path, cl_type) =
try
Env.lookup_class cl_name env
with Not_found ->
raise (Error (loc, Unbound_class cl_name))
in
let (params', _, vars', meths', self') = Ctype.instance_class cl_type in
(* Unify parameters *)
if List.length params <> List.length params' then
raise(Error(loc, Parameter_arity_mismatch
(path, List.length params', List.length params)));
List.iter2
(fun sty ty ->
let ty' = Typetexp.transl_simple_type var_env false sty in
try Ctype.unify var_env ty' ty with Ctype.Unify trace ->
raise(Error(sty.ptyp_loc, Parameter_mismatch trace)))
params params';
let vars_sig =
Vars.fold
(fun lab (mut, ty) v_sig ->
insert_value var_env lab Public mut ty loc v_sig)
vars' vars_sig
in
let meths_sig =
Meths.fold
(fun lab ty m_sig ->
let ty' =
try Meths.find lab m_sig with Not_found ->
Ctype.filter_method var_env lab Private self
in
begin try Ctype.unify env ty ty' with Ctype.Unify trace ->
raise(Error(loc, Method_type_mismatch (lab, trace)))
end;
Meths.add lab ty m_sig)
meths' meths_sig
in
(* Self type *)
let ty' = Ctype.expand_head var_env self' in
begin match ty'.desc with
Tobject (fi, _) ->
if ty' != Ctype.expand_head var_env self then begin
if not (Ctype.opened_object ty') then
begin try
Ctype.unify var_env self (Ctype.newobj (closed_scheme fi))
with Ctype.Unify _ ->
let lab = missing_method var_env ty' self in
raise(Error(loc, Closed_ancestor (cl.pcty_name, path, lab)))
end;
Ctype.unify var_env ty' self;
type_meth var_env loc self fi
end
| _ ->
fatal_error "Typeclass.type_class_field (type)"
end;
(vars_sig, meths_sig)
| Pctf_val (lab, priv, mut, sty, loc) ->
begin match sty with
Some sty ->
let ty = transl_simple_type var_env false sty in
(insert_value var_env lab priv mut ty loc vars_sig, meths_sig)
| None ->
(fst (change_value_status lab priv mut loc vars_sig), meths_sig)
end
| Pctf_virt (lab, priv, sty, loc) ->
let ty = transl_simple_type var_env false sty in
let ty'' = Ctype.filter_method var_env lab priv self in
let ty' = try Meths.find lab meths_sig with Not_found -> ty'' in
begin try Ctype.unify var_env ty ty' with Ctype.Unify trace ->
raise(Error(loc, Method_type_mismatch (lab, trace)))
end;
(vars_sig, Meths.add lab ty meths_sig)
| Pctf_meth (lab, priv, sty, loc) ->
let ty = transl_simple_type var_env false sty in
let ty'' = Ctype.filter_method var_env lab priv self in
let ty' = try Meths.find lab meths_sig with Not_found -> ty'' in
begin try Ctype.unify var_env ty ty' with Ctype.Unify trace ->
raise(Error(loc, Method_type_mismatch (lab, trace)))
end;
(vars_sig, Meths.add lab ty meths_sig)
let transl_class temp_env env
(cl, id, cl_id, obj_id, self, concr_meths, temp_cl,
temp_cl_params, cl_abbrev, temp_obj, temp_obj_params, abbrev)
=
reset_type_variables ();
Ctype.begin_def ();
(* Self type *)
let self = Ctype.instance self in
(* Introduce parameters *)
let params =
try
List.map (enter_type_variable true) (fst cl.pcty_param)
with Already_bound ->
raise(Error(snd cl.pcty_param, Repeated_parameter))
in
(* Translate constrained parameters *)
let cstr_params =
List.map (function (v, _, loc) -> type_variable loc v) cl.pcty_cstr
in
(* Bind self type variable *)
begin match cl.pcty_self with
Some v -> Ctype.unify temp_env self (enter_type_variable false v)
| None -> ()
end;
(* Add constraints *)
List.iter2
(fun (v, sty, loc) ty' ->
try
Ctype.unify temp_env (transl_simple_type temp_env false sty) ty'
with Ctype.Unify _ ->
raise(Error(loc, Unconsistent_constraint)))
cl.pcty_cstr cstr_params;
(* Translate argument types *)
let arg_sig = List.map (transl_simple_type temp_env false) cl.pcty_args in
(* Translate fields *)
let (vars_sig, meths_sig) =
List.fold_left (type_class_field env temp_env self cl)
(Vars.empty, Meths.empty) cl.pcty_field
in
(* Closeness of self *)
if cl.pcty_closed = Closed then
Ctype.close_object self;
(* Generalize class *)
Ctype.end_def ();
List.iter Ctype.generalize params;
List.iter Ctype.generalize arg_sig;
Vars.iter (fun l (m, t) -> Ctype.generalize t) vars_sig;
Meths.iter (fun l t -> Ctype.generalize t) meths_sig;
Ctype.generalize self;
(* Temporary class abbreviation *)
let (cl_params, cl_ty) = Ctype.instance_parameterized_type params self in
begin try Ctype.unify temp_env temp_cl cl_ty with Ctype.Unify _ ->
Ctype.remove_object_name temp_cl;
raise(Error(cl.pcty_loc, Abbrev_type_clash (cl_abbrev, cl_ty, temp_cl)))
end;
begin try
List.iter2 (Ctype.unify temp_env) temp_cl_params cl_params
with Ctype.Unify _ ->
raise(Error(cl.pcty_loc,
Bad_parameters (cl_id, cl_abbrev,
Ctype.newty (Tconstr (Path.Pident cl_id, cl_params,
ref Mnil)))))
end;
(* Object abbreviation and arguments for new *)
let (obj_params, arg_sig', obj_ty) =
Ctype.instance_parameterized_type_2 params arg_sig self
in
begin try Ctype.unify temp_env abbrev obj_ty with Ctype.Unify _ ->
raise(Error(cl.pcty_loc, Abbrev_type_clash (abbrev, obj_ty, temp_obj)))
end;
begin try
List.iter2 (Ctype.unify temp_env) temp_obj_params obj_params
with Ctype.Unify _ ->
raise(Error(cl.pcty_loc,
Bad_parameters (obj_id, abbrev,
Ctype.newty (Tconstr (Path.Pident obj_id, obj_params,
ref Mnil)))))
end;
Ctype.close_object temp_obj;
(* Temporary class signature *)
let cl_sig =
{ cty_params = params;
cty_args = arg_sig;
cty_vars = vars_sig;
cty_meths = meths_sig;
cty_self = self;
cty_concr = concr_meths;
cty_new = None }
in
let new_env = Env.add_class id cl_sig env in
((cl, id, cl_id, obj_id, cl_sig, abbrev, temp_obj,
temp_obj_params),
new_env)
let build_new_type temp_env env
(cl, id, cl_id, obj_id, cl_sig, abbrev, temp_obj,
temp_obj_params)
=
(* Modify constrainsts to ensure the object abbreviation is well-formed *)
let (params, args, vars, meths, self) = Ctype.instance_class cl_sig in
List.iter2 (Ctype.unify temp_env) params temp_obj_params;
(* Never fails *)
(* Hide private methods *)
Ctype.hide_private_methods cl_sig.cty_self;
(* Closeness of self (2) *)
if (cl.pcty_closed <> Closed) & not (Ctype.opened_object self) then
raise(Error(cl.pcty_loc, Closed_class cl.pcty_name));
equalize_methods temp_env self temp_obj;
(* self should not be an abbreviation (printtyp) *)
let exp_self = Ctype.expand_head temp_env self in
let new_ty =
if cl.pcty_kind = Concrete then
Some (List.fold_right
(fun arg ty -> Ctype.newty (Tarrow(arg, ty)))
args abbrev)
else
None
in
let public_methods =
match (Ctype.repr exp_self).desc with
Tobject (fi, _) ->
let (meths, _) = Ctype.flatten_fields fi in
List.map (function (lab, _, _) -> lab) meths
| _ -> fatal_error "Typeclass.build_new_type"
in
(* Check whether the class can be concrete *)
if cl.pcty_kind = Concrete then
List.iter
(function m ->
if not (Concr.mem m cl_sig.cty_concr) then
raise(Error(cl.pcty_loc, Virtual_class (cl.pcty_name, m))))
public_methods;
(* Final class type *)
let cl_sig =
{ cty_params = params;
cty_args = args;
cty_vars = vars;
cty_meths = meths;
cty_self = exp_self;
cty_concr = cl_sig.cty_concr;
cty_new = new_ty }
in let new_env = Env.add_class id cl_sig env in
((cl, id, cl_id, obj_id, cl_sig), new_env)
let make_abbrev env
(cl, id, cl_id, obj_id, cl_sig)
=
(* Class type abbreviation *)
let cl_abbrev =
{ type_params = cl_sig.cty_params;
type_arity = List.length cl_sig.cty_params;
type_kind = Type_abstract;
type_manifest = Some
(if cl.pcty_closed = Closed then
Ctype.newgenty (Tconstr(Path.Pident obj_id, cl_sig.cty_params,
ref Mnil))
else begin
Ctype.set_object_name cl_sig.cty_self cl_sig.cty_params obj_id;
cl_sig.cty_self
end) }
in let new_env = Env.add_type cl_id cl_abbrev env in
(* Object type abbreviation *)
Ctype.begin_def ();
let (obj_ty_params, obj_ty) =
Ctype.instance_parameterized_type cl_sig.cty_params cl_sig.cty_self
in
Ctype.close_object obj_ty;
Ctype.end_def ();
List.iter Ctype.generalize obj_ty_params;
begin match Ctype.closed_schema_verbose obj_ty with
None -> ()
| Some v ->
raise(Error(cl.pcty_loc,
Non_closed(obj_id, obj_ty_params, obj_ty, v)))
end;
Ctype.generalize obj_ty;
let obj_abbrev =
{ type_params = obj_ty_params;
type_arity = List.length obj_ty_params;
type_kind = Type_abstract;
type_manifest = Some (Ctype.unroll_abbrev obj_id obj_ty_params obj_ty) }
in let new_env = Env.add_type obj_id obj_abbrev new_env in
((id, cl_sig, cl_id, cl_abbrev, obj_id, obj_abbrev), new_env)
let rec transl_class_types env cl =
let info =
List.map
(function cl ->
(cl, Ident.create cl.pcty_name, Ident.create ("#" ^ cl.pcty_name)))
cl
in
Ctype.init_def(Ident.current_time());
Ctype.begin_def();
let (info, temp_env) = iter make_stub env info in
let (info, _) = iter (transl_class temp_env) env info in
let (info, new_env) = iter (build_new_type temp_env) env info in
Ctype.end_def ();
List.iter (fun (_, _, _, _, cl_sig) -> generalize_class cl_sig) info;
let (info, new_env) = iter make_abbrev new_env info in
(info, new_env)
(* Error report *)
open Format
let report_error = function
Duplicate_method s ->
print_string "Two methods are named"; print_space ();
print_string s
| Duplicate_variable s ->
print_string "Two instance variables are named"; print_space ();
print_string s
| Duplicate_super_variable s ->
print_string "Two ancestors are named"; print_space ();
print_string s
| Repeated_parameter ->
print_string "A type parameter occurs several times"
| Virtual_class (cl, met) ->
print_string "The class"; print_space ();
print_string cl; print_space ();
print_string "should be virtual: its method"; print_space ();
print_string met; print_space ();
print_string "is undefined"
| Closed_class cl ->
print_string "The class"; print_space ();
print_string cl; print_space ();
print_string "is closed, but not marked closed"
| Closed_ancestor (cl, anc, met) ->
print_string "The class"; print_space ();
print_string cl; print_space ();
print_string "inherits from the closed class"; print_space ();
Printtyp.path anc; print_space ();
print_string "which has no method"; print_space ();
print_string met
| Non_generalizable (id, params) ->
open_box 0;
Printtyp.reset ();
List.iter Printtyp.mark_loops params;
print_string "The";
List.iter (fun w -> print_space (); print_string w)
["type"; "parameters"; "of"; "this"; "class"; "contains";
"type"; "variables"; "that"; "cannot"; "be"; "generalized:"];
print_break 1 2;
Printtyp.type_scheme
{desc = Tconstr(Path.Pident id, params, ref Mnil); level = 0};
close_box ()
| Non_closed (id, args, typ, var) ->
open_box 0;
Printtyp.reset ();
List.iter Printtyp.mark_loops args;
Printtyp.mark_loops typ;
begin match var with
Ctype.Var v ->
print_string "The type variable"; print_space ();
Printtyp.type_expr v; print_space ();
print_string "is not bound in implicit type definition"
| _ ->
print_string "Unbound row variable in implicit type definition"
end;
print_break 1 2;
open_box 0;
Printtyp.type_expr
(Ctype.newty (Tconstr(Path.Pident id, args, ref Mnil)));
print_space (); print_string "="; print_space ();
Printtyp.type_expr typ;
close_box ();
close_box ();
print_space ();
print_string "It should be captured by a class type parameter"
| Mutable_var v ->
print_string "The variable"; print_space ();
print_string v; print_space ();
print_string "was mutable and is redefined as immutable"
| Undefined_var v ->
print_string "The variable"; print_space ();
print_string v; print_space ();
print_string "is undefined"
| Variable_type_mismatch (v, trace) ->
Printtyp.unification_error trace
(function () ->
print_string "The variable ";
print_string v; print_space ();
print_string "has type")
(function () ->
print_string "but is expected to have type")
| Method_type_mismatch (m, trace) ->
Printtyp.unification_error trace
(function () ->
print_string "The method ";
print_string m; print_space ();
print_string "has type")
(function () ->
print_string "but is expected to have type")
| Unconsistent_constraint ->
print_string "The class constraints are not consistent"
| Unbound_class cl ->
print_string "Unbound class"; print_space ();
Printtyp.longident cl
| Argument_type_mismatch trace ->
Printtyp.unification_error trace
(function () ->
print_string "This argument has type")
(function () ->
print_string "but is expected to have type")
| Abbrev_type_clash (abbrev, actual, expected) ->
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 ()
| 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 ()
| Illdefined_class s ->
print_string "The class "; print_string s;
print_string " is ill-defined"
| Parameter_mismatch trace ->
Printtyp.unification_error trace
(function () ->
print_string "The type parameter")
(function () ->
print_string "does not meet its constraint: it should be")
| Argument_arity_mismatch(p, expected, provided) ->
open_box 0;
print_string "The class "; Printtyp.path p;
print_space(); print_string "expects "; print_int expected;
print_string " argument(s),"; print_space();
print_string "but is here applied to "; print_int provided;
print_string " argument(s)";
close_box()
| Parameter_arity_mismatch(p, expected, provided) ->
open_box 0;
print_string "The class "; Printtyp.path p;
print_space(); print_string "expects "; print_int expected;
print_string " type parameter(s),"; print_space();
print_string "but is here applied to "; print_int provided;
print_string " type parameter(s)";
close_box()