ocaml/toplevel/genprintval.ml

366 lines
14 KiB
OCaml

(***********************************************************************)
(* *)
(* Objective Caml *)
(* *)
(* Xavier Leroy and 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. *)
(* *)
(***********************************************************************)
(* $Id$ *)
(* To print values *)
open Misc
open Format
open Longident
open Path
open Types
open Outcometree
module type OBJ =
sig
type t
val obj : t -> 'a
val is_block : t -> bool
val tag : t -> int
val size : t -> int
val field : t -> int -> t
end
module type EVALPATH =
sig
type value
val eval_path: Path.t -> value
exception Error
val same_value: value -> value -> bool
end
module type S =
sig
type t
val install_printer :
Path.t -> Types.type_expr -> (formatter -> t -> unit) -> unit
val remove_printer : Path.t -> unit
val outval_of_untyped_exception : t -> Outcometree.out_value
val outval_of_value :
int -> int ->
(int -> t -> Types.type_expr -> Outcometree.out_value option) ->
Env.t -> t -> type_expr -> Outcometree.out_value
end
module Make(O : OBJ)(EVP : EVALPATH with type value = O.t) = struct
type t = O.t
(* Given an exception value, we cannot recover its type,
hence we cannot print its arguments in general.
Here, we do a feeble attempt to print
integer, string and float arguments... *)
let outval_of_untyped_exception_args obj start_offset =
if O.size obj > start_offset then begin
let list = ref [] in
for i = start_offset to O.size obj - 1 do
let arg = O.field obj i in
if not (O.is_block arg) then
list := Oval_int (O.obj arg : int) :: !list
(* Note: this could be a char or a constant constructor... *)
else if O.tag arg = Obj.string_tag then
list :=
Oval_string (String.escaped (O.obj arg : string)) :: !list
else if O.tag arg = Obj.double_tag then
list := Oval_float (O.obj arg : float) :: !list
else
list := Oval_constr (Oide_ident "_", []) :: !list
done;
List.rev !list
end
else []
let outval_of_untyped_exception bucket =
let name = (O.obj(O.field(O.field bucket 0) 0) : string) in
let args =
if (name = "Match_failure"
|| name = "Assert_failure"
|| name = "Undefined_recursive_module")
&& O.size bucket = 2
&& O.tag(O.field bucket 1) = 0
then outval_of_untyped_exception_args (O.field bucket 1) 0
else outval_of_untyped_exception_args bucket 1 in
Oval_constr (Oide_ident name, args)
(* The user-defined printers. Also used for some builtin types. *)
let printers = ref ([
Pident(Ident.create "print_int"), Predef.type_int,
(fun x -> Oval_int (O.obj x : int));
Pident(Ident.create "print_float"), Predef.type_float,
(fun x -> Oval_float (O.obj x : float));
Pident(Ident.create "print_char"), Predef.type_char,
(fun x -> Oval_char (O.obj x : char));
Pident(Ident.create "print_string"), Predef.type_string,
(fun x -> Oval_string (O.obj x : string));
Pident(Ident.create "print_int32"), Predef.type_int32,
(fun x -> Oval_int32 (O.obj x : int32));
Pident(Ident.create "print_nativeint"), Predef.type_nativeint,
(fun x -> Oval_nativeint (O.obj x : nativeint));
Pident(Ident.create "print_int64"), Predef.type_int64,
(fun x -> Oval_int64 (O.obj x : int64))
] : (Path.t * type_expr * (O.t -> Outcometree.out_value)) list)
let install_printer path ty fn =
let print_val ppf obj =
try fn ppf obj with
| exn ->
fprintf ppf "<printer %a raised an exception>" Printtyp.path path in
let printer obj = Oval_printer (fun ppf -> print_val ppf obj) in
printers := (path, ty, printer) :: !printers
let remove_printer path =
let rec remove = function
| [] -> raise Not_found
| (p, ty, fn as printer) :: rem ->
if Path.same p path then rem else printer :: remove rem in
printers := remove !printers
let find_printer env ty =
let rec find = function
| [] -> raise Not_found
| (name, sch, printer) :: remainder ->
if Ctype.moregeneral env false sch ty
then printer
else find remainder
in find !printers
(* Print a constructor or label, giving it the same prefix as the type
it comes from. Attempt to omit the prefix if the type comes from
a module that has been opened. *)
let tree_of_qualified lookup_fun env ty_path name =
match ty_path with
| Pident id ->
Oide_ident name
| Pdot(p, s, pos) ->
if try
match (lookup_fun (Lident name) env).desc with
| Tconstr(ty_path', _, _) -> Path.same ty_path ty_path'
| _ -> false
with Not_found -> false
then Oide_ident name
else Oide_dot (Printtyp.tree_of_path p, name)
| Papply(p1, p2) ->
Printtyp.tree_of_path ty_path
let tree_of_constr =
tree_of_qualified
(fun lid env -> (Env.lookup_constructor lid env).cstr_res)
and tree_of_label =
tree_of_qualified (fun lid env -> (Env.lookup_label lid env).lbl_res)
(* An abstract type *)
let abstract_type =
Ctype.newty (Tconstr (Pident (Ident.create "abstract"), [], ref Mnil))
(* The main printing function *)
let outval_of_value max_steps max_depth check_depth env obj ty =
let printer_steps = ref max_steps in
let rec tree_of_val depth obj ty =
decr printer_steps;
if !printer_steps < 0 || depth < 0 then Oval_ellipsis
else begin
try
find_printer env ty obj
with Not_found ->
match (Ctype.repr ty).desc with
| Tvar ->
Oval_stuff "<poly>"
| Tarrow(_, ty1, ty2, _) ->
Oval_stuff "<fun>"
| Ttuple(ty_list) ->
Oval_tuple (tree_of_val_list 0 depth obj ty_list)
| Tconstr(path, [], _) when Path.same path Predef.path_exn ->
tree_of_exception depth obj
| Tconstr(path, [ty_arg], _)
when Path.same path Predef.path_list ->
if O.is_block obj then
match check_depth depth obj ty with
Some x -> x
| None ->
let rec tree_of_conses tree_list obj =
if !printer_steps < 0 || depth < 0 then
Oval_ellipsis :: tree_list
else if O.is_block obj then
let tree =
tree_of_val (depth - 1) (O.field obj 0) ty_arg in
let next_obj = O.field obj 1 in
tree_of_conses (tree :: tree_list) next_obj
else tree_list
in
Oval_list (List.rev (tree_of_conses [] obj))
else
Oval_list []
| Tconstr(path, [ty_arg], _)
when Path.same path Predef.path_array ->
let length = O.size obj in
if length > 0 then
match check_depth depth obj ty with
Some x -> x
| None ->
let rec tree_of_items tree_list i =
if !printer_steps < 0 || depth < 0 then
Oval_ellipsis :: tree_list
else if i < length then
let tree =
tree_of_val (depth - 1) (O.field obj i) ty_arg in
tree_of_items (tree :: tree_list) (i + 1)
else tree_list
in
Oval_array (List.rev (tree_of_items [] 0))
else
Oval_array []
| Tconstr (path, [ty_arg], _)
when Path.same path Predef.path_lazy_t ->
if Lazy.lazy_is_val (O.obj obj)
then let v = tree_of_val depth (Lazy.force (O.obj obj)) ty_arg in
Oval_constr (Oide_ident "lazy", [v])
else Oval_stuff "<lazy>"
| Tconstr(path, ty_list, _) ->
begin try
let decl = Env.find_type path env in
match decl with
| {type_kind = Type_abstract; type_manifest = None} ->
Oval_stuff "<abstr>"
| {type_kind = Type_abstract; type_manifest = Some body} ->
tree_of_val depth obj
(try Ctype.apply env decl.type_params body ty_list with
Ctype.Cannot_apply -> abstract_type)
| {type_kind = Type_variant constr_list} ->
let tag =
if O.is_block obj
then Cstr_block(O.tag obj)
else Cstr_constant(O.obj obj) in
let (constr_name, constr_args) =
Datarepr.find_constr_by_tag tag constr_list in
let ty_args =
List.map
(function ty ->
try Ctype.apply env decl.type_params ty ty_list with
Ctype.Cannot_apply -> abstract_type)
constr_args in
tree_of_constr_with_args (tree_of_constr env path)
constr_name 0 depth obj ty_args
| {type_kind = Type_record(lbl_list, rep)} ->
begin match check_depth depth obj ty with
Some x -> x
| None ->
let rec tree_of_fields pos = function
| [] -> []
| (lbl_name, _, lbl_arg) :: remainder ->
let ty_arg =
try
Ctype.apply env decl.type_params lbl_arg
ty_list
with
Ctype.Cannot_apply -> abstract_type in
let lid = tree_of_label env path lbl_name in
let v =
tree_of_val (depth - 1) (O.field obj pos)
ty_arg
in
(lid, v) :: tree_of_fields (pos + 1) remainder
in
Oval_record (tree_of_fields 0 lbl_list)
end
with
Not_found -> (* raised by Env.find_type *)
Oval_stuff "<abstr>"
| Datarepr.Constr_not_found -> (* raised by find_constr_by_tag *)
Oval_stuff "<unknown constructor>"
end
| Tvariant row ->
let row = Btype.row_repr row in
if O.is_block obj then
let tag : int = O.obj (O.field obj 0) in
let rec find = function
| (l, f) :: fields ->
if Btype.hash_variant l = tag then
match Btype.row_field_repr f with
| Rpresent(Some ty) | Reither(_,[ty],_,_) ->
let args =
tree_of_val (depth - 1) (O.field obj 1) ty in
Oval_variant (l, Some args)
| _ -> find fields
else find fields
| [] -> Oval_stuff "<variant>" in
find row.row_fields
else
let tag : int = O.obj obj in
let rec find = function
| (l, _) :: fields ->
if Btype.hash_variant l = tag then
Oval_variant (l, None)
else find fields
| [] -> Oval_stuff "<variant>" in
find row.row_fields
| Tobject (_, _) ->
Oval_stuff "<obj>"
| Tsubst ty ->
tree_of_val (depth - 1) obj ty
| Tfield(_, _, _, _) | Tnil | Tlink _ ->
fatal_error "Printval.outval_of_value"
| Tpoly (ty, _) ->
tree_of_val (depth - 1) obj ty
| Tunivar ->
Oval_stuff "<poly>"
| Tpackage _ ->
Oval_stuff "<module>"
end
and tree_of_val_list start depth obj ty_list =
let rec tree_list i = function
| [] -> []
| ty :: ty_list ->
let tree = tree_of_val (depth - 1) (O.field obj i) ty in
tree :: tree_list (i + 1) ty_list in
tree_list start ty_list
and tree_of_constr_with_args
tree_of_cstr cstr_name start depth obj ty_args =
let lid = tree_of_cstr cstr_name in
let args = tree_of_val_list start depth obj ty_args in
Oval_constr (lid, args)
and tree_of_exception depth bucket =
let name = (O.obj(O.field(O.field bucket 0) 0) : string) in
let lid = Longident.parse name in
try
(* Attempt to recover the constructor description for the exn
from its name *)
let cstr = Env.lookup_constructor lid env in
let path =
match cstr.cstr_tag with
Cstr_exception p -> p | _ -> raise Not_found in
(* Make sure this is the right exception and not an homonym,
by evaluating the exception found and comparing with the
identifier contained in the exception bucket *)
if not (EVP.same_value (O.field bucket 0) (EVP.eval_path path))
then raise Not_found;
tree_of_constr_with_args
(fun x -> Oide_ident x) name 1 depth bucket cstr.cstr_args
with Not_found | EVP.Error ->
match check_depth depth bucket ty with
Some x -> x
| None -> outval_of_untyped_exception bucket
in tree_of_val max_depth obj ty
end