ocaml/typing/types.ml

297 lines
9.3 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 Q Public License version 1.0. *)
(* *)
(***********************************************************************)
(* Representation of types and declarations *)
open Asttypes
(* Type expressions for the core language *)
type type_expr =
{ mutable desc: type_desc;
mutable level: int;
mutable id: int }
and type_desc =
Tvar of string option
| Tarrow of label * type_expr * type_expr * commutable
| Ttuple of type_expr list
| Tconstr of Path.t * type_expr list * abbrev_memo ref
| Tobject of type_expr * (Path.t * type_expr list) option ref
| Tfield of string * field_kind * type_expr * type_expr
| Tnil
| Tlink of type_expr
| Tsubst of type_expr (* for copying *)
| Tvariant of row_desc
| Tunivar of string option
| Tpoly of type_expr * type_expr list
| Tpackage of Path.t * Longident.t list * type_expr list
and row_desc =
{ row_fields: (label * row_field) list;
row_more: type_expr;
row_bound: unit;
row_closed: bool;
row_fixed: bool;
row_name: (Path.t * type_expr list) option }
and row_field =
Rpresent of type_expr option
| Reither of bool * type_expr list * bool * row_field option ref
(* 1st true denotes a constant constructor *)
(* 2nd true denotes a tag in a pattern matching, and
is erased later *)
| Rabsent
and abbrev_memo =
Mnil
| Mcons of private_flag * Path.t * type_expr * type_expr * abbrev_memo
| Mlink of abbrev_memo ref
and field_kind =
Fvar of field_kind option ref
| Fpresent
| Fabsent
and commutable =
Cok
| Cunknown
| Clink of commutable ref
module TypeOps = struct
type t = type_expr
let compare t1 t2 = t1.id - t2.id
let hash t = t.id
let equal t1 t2 = t1 == t2
end
(* Maps of methods and instance variables *)
module OrderedString =
struct type t = string let compare (x:t) y = compare x y end
module Meths = Map.Make(OrderedString)
module Vars = Meths
(* Value descriptions *)
type value_description =
{ val_type: type_expr; (* Type of the value *)
val_kind: value_kind;
val_loc: Location.t;
val_attributes: Parsetree.attributes;
}
and value_kind =
Val_reg (* Regular value *)
| Val_prim of Primitive.description (* Primitive *)
| Val_ivar of mutable_flag * string (* Instance variable (mutable ?) *)
| Val_self of (Ident.t * type_expr) Meths.t ref *
(Ident.t * Asttypes.mutable_flag *
Asttypes.virtual_flag * type_expr) Vars.t ref *
string * type_expr
(* Self *)
| Val_anc of (string * Ident.t) list * string
(* Ancestor *)
| Val_unbound (* Unbound variable *)
(* Constructor descriptions *)
type constructor_description =
{ cstr_name: string; (* Constructor name *)
cstr_res: type_expr; (* Type of the result *)
cstr_existentials: type_expr list; (* list of existentials *)
cstr_args: type_expr list; (* Type of the arguments *)
cstr_arity: int; (* Number of arguments *)
cstr_tag: constructor_tag; (* Tag for heap blocks *)
cstr_consts: int; (* Number of constant constructors *)
cstr_nonconsts: int; (* Number of non-const constructors *)
cstr_normal: int; (* Number of non generalized constrs *)
cstr_generalized: bool; (* Constrained return type? *)
cstr_private: private_flag; (* Read-only constructor? *)
cstr_loc: Location.t;
cstr_attributes: Parsetree.attributes;
}
and constructor_tag =
Cstr_constant of int (* Constant constructor (an int) *)
| Cstr_block of int (* Regular constructor (a block) *)
| Cstr_exception of Path.t * Location.t (* Exception constructor *)
(* Record label descriptions *)
type label_description =
{ lbl_name: string; (* Short name *)
lbl_res: type_expr; (* Type of the result *)
lbl_arg: type_expr; (* Type of the argument *)
lbl_mut: mutable_flag; (* Is this a mutable field? *)
lbl_pos: int; (* Position in block *)
lbl_all: label_description array; (* All the labels in this type *)
lbl_repres: record_representation; (* Representation for this record *)
lbl_private: private_flag; (* Read-only field? *)
lbl_loc: Location.t;
lbl_attributes: Parsetree.attributes;
}
and record_representation =
Record_regular (* All fields are boxed / tagged *)
| Record_float (* All fields are floats *)
(* Variance *)
module Variance = struct
type t = int
type f = May_pos | May_neg | May_weak | Inj | Pos | Neg | Inv
let single = function
| May_pos -> 1
| May_neg -> 2
| May_weak -> 4
| Inj -> 8
| Pos -> 16
| Neg -> 32
| Inv -> 64
let union v1 v2 = v1 lor v2
let inter v1 v2 = v1 land v2
let subset v1 v2 = (v1 land v2 = v1)
let set x b v =
if b then v lor single x else v land (lnot (single x))
let mem x = subset (single x)
let null = 0
let may_inv = 7
let full = 127
let covariant = single May_pos lor single Pos lor single Inj
let swap f1 f2 v =
let v' = set f1 (mem f2 v) v in set f2 (mem f1 v) v'
let conjugate v = swap May_pos May_neg (swap Pos Neg v)
let get_upper v = (mem May_pos v, mem May_neg v)
let get_lower v = (mem Pos v, mem Neg v, mem Inv v, mem Inj v)
end
(* Type definitions *)
type type_declaration =
{ type_params: type_expr list;
type_arity: int;
type_kind: type_kind;
type_private: private_flag;
type_manifest: type_expr option;
type_variance: Variance.t list;
type_newtype_level: (int * int) option;
type_loc: Location.t;
type_attributes: Parsetree.attributes;
}
and type_kind =
Type_abstract
| Type_record of label_declaration list * record_representation
| Type_variant of constructor_declaration list
and label_declaration =
{
ld_id: Ident.t;
ld_mutable: mutable_flag;
ld_type: type_expr;
ld_loc: Location.t;
ld_attributes: Parsetree.attributes;
}
and constructor_declaration =
{
cd_id: Ident.t;
cd_args: type_expr list;
cd_res: type_expr option;
cd_loc: Location.t;
cd_attributes: Parsetree.attributes;
}
and type_transparence =
Type_public (* unrestricted expansion *)
| Type_new (* "new" type *)
| Type_private (* private type *)
type exception_declaration =
{ exn_args: type_expr list;
exn_loc: Location.t;
exn_attributes: Parsetree.attributes;
}
(* Type expressions for the class language *)
module Concr = Set.Make(OrderedString)
type class_type =
Cty_constr of Path.t * type_expr list * class_type
| Cty_signature of class_signature
| Cty_arrow of label * type_expr * class_type
and class_signature =
{ csig_self: type_expr;
csig_vars:
(Asttypes.mutable_flag * Asttypes.virtual_flag * type_expr) Vars.t;
csig_concr: Concr.t;
csig_inher: (Path.t * type_expr list) list }
type class_declaration =
{ cty_params: type_expr list;
mutable cty_type: class_type;
cty_path: Path.t;
cty_new: type_expr option;
cty_variance: Variance.t list;
cty_loc: Location.t;
cty_attributes: Parsetree.attributes;
}
type class_type_declaration =
{ clty_params: type_expr list;
clty_type: class_type;
clty_path: Path.t;
clty_variance: Variance.t list;
clty_loc: Location.t;
clty_attributes: Parsetree.attributes;
}
(* Type expressions for the module language *)
type module_type =
Mty_ident of Path.t
| Mty_signature of signature
| Mty_functor of Ident.t * module_type * module_type
| Mty_alias of Path.t
and signature = signature_item list
and signature_item =
Sig_value of Ident.t * value_description
| Sig_type of Ident.t * type_declaration * rec_status
| Sig_exception of Ident.t * exception_declaration
| Sig_module of Ident.t * module_declaration * rec_status
| Sig_modtype of Ident.t * modtype_declaration
| Sig_class of Ident.t * class_declaration * rec_status
| Sig_class_type of Ident.t * class_type_declaration * rec_status
and module_declaration =
{
md_type: module_type;
md_attributes: Parsetree.attributes;
}
and modtype_declaration =
{
mtd_type: module_type option; (* Nonte: abstract *)
mtd_attributes: Parsetree.attributes;
}
and rec_status =
Trec_not (* not recursive *)
| Trec_first (* first in a recursive group *)
| Trec_next (* not first in a recursive group *)