574 lines
22 KiB
OCaml
574 lines
22 KiB
OCaml
(***********************************************************************)
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(* *)
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(* OCaml *)
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(* *)
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(* Xavier Leroy and Jerome Vouillon, projet Cristal, INRIA Rocquencourt*)
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(* *)
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(* Copyright 1996 Institut National de Recherche en Informatique et *)
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(* en Automatique. All rights reserved. This file is distributed *)
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(* under the terms of the Q Public License version 1.0. *)
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(* *)
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(***********************************************************************)
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(* To print values *)
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open Misc
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open Format
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open Longident
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open Path
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open Types
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open Outcometree
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module type OBJ =
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sig
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type t
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val obj : t -> 'a
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val is_block : t -> bool
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val tag : t -> int
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val size : t -> int
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val field : t -> int -> t
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end
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module type EVALPATH =
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sig
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type valu
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val eval_path: Env.t -> Path.t -> valu
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exception Error
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val same_value: valu -> valu -> bool
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end
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type ('a, 'b) gen_printer =
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| Zero of 'b
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| Succ of ('a -> ('a, 'b) gen_printer)
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module type S =
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sig
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type t
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val install_printer :
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Path.t -> Types.type_expr -> (formatter -> t -> unit) -> unit
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val install_generic_printer :
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Path.t -> Path.t ->
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(int -> (int -> t -> Outcometree.out_value,
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t -> Outcometree.out_value) gen_printer) ->
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unit
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val install_generic_printer' :
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Path.t -> Path.t ->
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(formatter -> t -> unit,
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formatter -> t -> unit) gen_printer ->
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unit
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val remove_printer : Path.t -> unit
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val outval_of_untyped_exception : t -> Outcometree.out_value
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val outval_of_value :
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int -> int ->
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(int -> t -> Types.type_expr -> Outcometree.out_value option) ->
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Env.t -> t -> type_expr -> Outcometree.out_value
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end
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module Make(O : OBJ)(EVP : EVALPATH with type valu = O.t) = struct
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type t = O.t
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module ObjTbl = Hashtbl.Make(struct
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type t = O.t
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let equal = (==)
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let hash x =
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try
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Hashtbl.hash x
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with exn -> 0
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end)
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(* Given an exception value, we cannot recover its type,
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hence we cannot print its arguments in general.
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Here, we do a feeble attempt to print
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integer, string and float arguments... *)
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let outval_of_untyped_exception_args obj start_offset =
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if O.size obj > start_offset then begin
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let list = ref [] in
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for i = start_offset to O.size obj - 1 do
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let arg = O.field obj i in
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if not (O.is_block arg) then
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list := Oval_int (O.obj arg : int) :: !list
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(* Note: this could be a char or a constant constructor... *)
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else if O.tag arg = Obj.string_tag then
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list :=
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Oval_string (String.escaped (O.obj arg : string)) :: !list
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else if O.tag arg = Obj.double_tag then
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list := Oval_float (O.obj arg : float) :: !list
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else
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list := Oval_constr (Oide_ident "_", []) :: !list
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done;
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List.rev !list
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end
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else []
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let outval_of_untyped_exception bucket =
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if O.tag bucket <> 0 then
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Oval_constr (Oide_ident (O.obj (O.field bucket 0) : string), [])
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else
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let name = (O.obj(O.field(O.field bucket 0) 0) : string) in
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let args =
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if (name = "Match_failure"
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|| name = "Assert_failure"
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|| name = "Undefined_recursive_module")
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&& O.size bucket = 2
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&& O.tag(O.field bucket 1) = 0
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then outval_of_untyped_exception_args (O.field bucket 1) 0
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else outval_of_untyped_exception_args bucket 1 in
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Oval_constr (Oide_ident name, args)
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(* The user-defined printers. Also used for some builtin types. *)
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type printer =
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| Simple of Types.type_expr * (O.t -> Outcometree.out_value)
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| Generic of Path.t * (int -> (int -> O.t -> Outcometree.out_value,
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O.t -> Outcometree.out_value) gen_printer)
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let printers = ref ([
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( Pident(Ident.create "print_int"),
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Simple (Predef.type_int,
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(fun x -> Oval_int (O.obj x : int))) );
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( Pident(Ident.create "print_float"),
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Simple (Predef.type_float,
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(fun x -> Oval_float (O.obj x : float))) );
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( Pident(Ident.create "print_char"),
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Simple (Predef.type_char,
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(fun x -> Oval_char (O.obj x : char))) );
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( Pident(Ident.create "print_string"),
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Simple (Predef.type_string,
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(fun x -> Oval_string (O.obj x : string))) );
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( Pident(Ident.create "print_int32"),
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Simple (Predef.type_int32,
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(fun x -> Oval_int32 (O.obj x : int32))) );
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( Pident(Ident.create "print_nativeint"),
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Simple (Predef.type_nativeint,
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(fun x -> Oval_nativeint (O.obj x : nativeint))) );
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( Pident(Ident.create "print_int64"),
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Simple (Predef.type_int64,
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(fun x -> Oval_int64 (O.obj x : int64)) ))
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] : (Path.t * printer) list)
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let exn_printer ppf path =
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fprintf ppf "<printer %a raised an exception>" Printtyp.path path
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let out_exn path =
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Oval_printer (fun ppf -> exn_printer ppf path)
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let install_printer path ty fn =
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let print_val ppf obj =
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try fn ppf obj with exn -> exn_printer ppf path in
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let printer obj = Oval_printer (fun ppf -> print_val ppf obj) in
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printers := (path, Simple (ty, printer)) :: !printers
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let install_generic_printer function_path constr_path fn =
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printers := (function_path, Generic (constr_path, fn)) :: !printers
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let install_generic_printer' function_path ty_path fn =
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let rec build gp depth =
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match gp with
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| Zero fn ->
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let out_printer obj =
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let printer ppf =
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try fn ppf obj with _ -> exn_printer ppf function_path in
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Oval_printer printer in
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Zero out_printer
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| Succ fn ->
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let print_val fn_arg =
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let print_arg ppf o =
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!Oprint.out_value ppf (fn_arg (depth+1) o) in
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build (fn print_arg) depth in
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Succ print_val in
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printers := (function_path, Generic (ty_path, build fn)) :: !printers
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let remove_printer path =
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let rec remove = function
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| [] -> raise Not_found
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| ((p, _) as printer) :: rem ->
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if Path.same p path then rem else printer :: remove rem in
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printers := remove !printers
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(* Print a constructor or label, giving it the same prefix as the type
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it comes from. Attempt to omit the prefix if the type comes from
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a module that has been opened. *)
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let tree_of_qualified lookup_fun env ty_path name =
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match ty_path with
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| Pident id ->
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Oide_ident name
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| Pdot(p, s, pos) ->
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if try
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match (lookup_fun (Lident name) env).desc with
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| Tconstr(ty_path', _, _) -> Path.same ty_path ty_path'
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| _ -> false
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with Not_found -> false
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then Oide_ident name
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else Oide_dot (Printtyp.tree_of_path p, name)
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| Papply(p1, p2) ->
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Printtyp.tree_of_path ty_path
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let tree_of_constr =
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tree_of_qualified
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(fun lid env -> (Env.lookup_constructor lid env).cstr_res)
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and tree_of_label =
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tree_of_qualified (fun lid env -> (Env.lookup_label lid env).lbl_res)
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(* An abstract type *)
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let abstract_type =
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Ctype.newty (Tconstr (Pident (Ident.create "abstract"), [], ref Mnil))
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(* The main printing function *)
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let outval_of_value max_steps max_depth check_depth env obj ty =
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let printer_steps = ref max_steps in
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let nested_values = ObjTbl.create 8 in
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let nest_gen err f depth obj ty =
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let repr = obj in
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if not (O.is_block repr) then
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f depth obj ty
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else
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if ObjTbl.mem nested_values repr then
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err
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else begin
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ObjTbl.add nested_values repr ();
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let ret = f depth obj ty in
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ObjTbl.remove nested_values repr;
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ret
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end
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in
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let nest f = nest_gen (Oval_stuff "<cycle>") f in
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let rec tree_of_val depth obj ty =
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decr printer_steps;
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if !printer_steps < 0 || depth < 0 then Oval_ellipsis
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else begin
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try
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find_printer depth env ty obj
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with Not_found ->
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match (Ctype.repr ty).desc with
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| Tvar _ | Tunivar _ ->
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Oval_stuff "<poly>"
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| Tarrow(_, ty1, ty2, _) ->
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Oval_stuff "<fun>"
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| Ttuple(ty_list) ->
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Oval_tuple (tree_of_val_list 0 depth obj ty_list)
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| Tconstr(path, [ty_arg], _)
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when Path.same path Predef.path_list ->
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if O.is_block obj then
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match check_depth depth obj ty with
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Some x -> x
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| None ->
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let rec tree_of_conses tree_list depth obj ty_arg =
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if !printer_steps < 0 || depth < 0 then
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Oval_ellipsis :: tree_list
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else if O.is_block obj then
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let tree =
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nest tree_of_val (depth - 1) (O.field obj 0) ty_arg
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in
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let next_obj = O.field obj 1 in
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nest_gen (Oval_stuff "<cycle>" :: tree :: tree_list)
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(tree_of_conses (tree :: tree_list))
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depth next_obj ty_arg
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else tree_list
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in
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Oval_list (List.rev (tree_of_conses [] depth obj ty_arg))
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else
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Oval_list []
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| Tconstr(path, [ty_arg], _)
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when Path.same path Predef.path_array ->
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let length = O.size obj in
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if length > 0 then
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match check_depth depth obj ty with
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Some x -> x
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| None ->
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let rec tree_of_items tree_list i =
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if !printer_steps < 0 || depth < 0 then
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Oval_ellipsis :: tree_list
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else if i < length then
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let tree =
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nest tree_of_val (depth - 1) (O.field obj i) ty_arg
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in
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tree_of_items (tree :: tree_list) (i + 1)
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else tree_list
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in
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Oval_array (List.rev (tree_of_items [] 0))
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else
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Oval_array []
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| Tconstr (path, [ty_arg], _)
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when Path.same path Predef.path_lazy_t ->
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let obj_tag = O.tag obj in
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(* Lazy values are represented in three possible ways:
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1. a lazy thunk that is not yet forced has tag
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Obj.lazy_tag
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2. a lazy thunk that has just been forced has tag
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Obj.forward_tag; its first field is the forced
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result, which we can print
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3. when the GC moves a forced trunk with forward_tag,
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or when a thunk is directly created from a value,
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we get a third representation where the value is
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directly exposed, without the Obj.forward_tag
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(if its own tag is not ambiguous, that is neither
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lazy_tag nor forward_tag)
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Note that using Lazy.is_val and Lazy.force would be
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unsafe, because they use the Obj.* functions rather
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than the O.* functions of the functor argument, and
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would thus crash if called from the toplevel
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(debugger/printval instantiates Genprintval.Make with
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an Obj module talking over a socket).
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*)
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if obj_tag = Obj.lazy_tag then Oval_stuff "<lazy>"
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else begin
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let forced_obj =
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if obj_tag = Obj.forward_tag then O.field obj 0 else obj
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in
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(* calling oneself recursively on forced_obj risks
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having a false positive for cycle detection;
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indeed, in case (3) above, the value is stored
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as-is instead of being wrapped in a forward
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pointer. It means that, for (lazy "foo"), we have
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forced_obj == obj
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and it is easy to wrongly print (lazy <cycle>) in such
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a case (PR#6669).
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Unfortunately, there is a corner-case that *is*
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a real cycle: using -rectypes one can define
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let rec x = lazy x
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which creates a Forward_tagged block that points to
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itself. For this reason, we still "nest"
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(detect head cycles) on forward tags.
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*)
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let v =
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if obj_tag = Obj.forward_tag
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then nest tree_of_val depth forced_obj ty_arg
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else tree_of_val depth forced_obj ty_arg
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in
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Oval_constr (Oide_ident "lazy", [v])
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end
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| Tconstr(path, ty_list, _) -> begin
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try
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let decl = Env.find_type path env in
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match decl with
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| {type_kind = Type_abstract; type_manifest = None} ->
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Oval_stuff "<abstr>"
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| {type_kind = Type_abstract; type_manifest = Some body} ->
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tree_of_val depth obj
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(try Ctype.apply env decl.type_params body ty_list with
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Ctype.Cannot_apply -> abstract_type)
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| {type_kind = Type_variant constr_list} ->
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let tag =
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if O.is_block obj
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then Cstr_block(O.tag obj)
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else Cstr_constant(O.obj obj) in
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let {cd_id;cd_args;cd_res} =
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Datarepr.find_constr_by_tag tag constr_list in
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let type_params =
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match cd_res with
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Some t ->
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begin match (Ctype.repr t).desc with
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Tconstr (_,params,_) ->
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params
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| _ -> assert false end
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| None -> decl.type_params
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in
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begin
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match cd_args with
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| Cstr_tuple l ->
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let ty_args =
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List.map
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(function ty ->
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try Ctype.apply env type_params ty ty_list with
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Ctype.Cannot_apply -> abstract_type)
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l
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in
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tree_of_constr_with_args (tree_of_constr env path)
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(Ident.name cd_id) false 0 depth obj
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ty_args
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| Cstr_record lbls ->
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let r =
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tree_of_record_fields depth
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env path type_params ty_list
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lbls 0 obj
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in
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Oval_constr(tree_of_constr env path
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(Ident.name cd_id),
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[ r ])
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end
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| {type_kind = Type_record(lbl_list, rep)} ->
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begin match check_depth depth obj ty with
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Some x -> x
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| None ->
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let pos =
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match rep with
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| Record_extension -> 1
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| _ -> 0
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in
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tree_of_record_fields depth
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env path decl.type_params ty_list
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lbl_list pos obj
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end
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| {type_kind = Type_open} ->
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tree_of_extension path depth obj
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with
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Not_found -> (* raised by Env.find_type *)
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Oval_stuff "<abstr>"
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| Datarepr.Constr_not_found -> (* raised by find_constr_by_tag *)
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Oval_stuff "<unknown constructor>"
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end
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| Tvariant row ->
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let row = Btype.row_repr row in
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if O.is_block obj then
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let tag : int = O.obj (O.field obj 0) in
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let rec find = function
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| (l, f) :: fields ->
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if Btype.hash_variant l = tag then
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match Btype.row_field_repr f with
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| Rpresent(Some ty) | Reither(_,[ty],_,_) ->
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let args =
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nest tree_of_val (depth - 1) (O.field obj 1) ty
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in
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Oval_variant (l, Some args)
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| _ -> find fields
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else find fields
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| [] -> Oval_stuff "<variant>" in
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find row.row_fields
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else
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let tag : int = O.obj obj in
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let rec find = function
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| (l, _) :: fields ->
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if Btype.hash_variant l = tag then
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Oval_variant (l, None)
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else find fields
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| [] -> Oval_stuff "<variant>" in
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find row.row_fields
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| Tobject (_, _) ->
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Oval_stuff "<obj>"
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| Tsubst ty ->
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tree_of_val (depth - 1) obj ty
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| Tfield(_, _, _, _) | Tnil | Tlink _ ->
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fatal_error "Printval.outval_of_value"
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| Tpoly (ty, _) ->
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tree_of_val (depth - 1) obj ty
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| Tpackage _ ->
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Oval_stuff "<module>"
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end
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and tree_of_record_fields depth env path type_params ty_list
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lbl_list pos obj =
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let rec tree_of_fields pos = function
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| [] -> []
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| {ld_id; ld_type} :: remainder ->
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let ty_arg =
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try
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Ctype.apply env type_params ld_type
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ty_list
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with
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Ctype.Cannot_apply -> abstract_type in
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let name = Ident.name ld_id in
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(* PR#5722: print full module path only
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for first record field *)
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let lid =
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if pos = 0 then tree_of_label env path name
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else Oide_ident name
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and v =
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nest tree_of_val (depth - 1) (O.field obj pos)
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ty_arg
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in
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(lid, v) :: tree_of_fields (pos + 1) remainder
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in
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Oval_record (tree_of_fields pos lbl_list)
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and tree_of_val_list start depth obj ty_list =
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let rec tree_list i = function
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| [] -> []
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| ty :: ty_list ->
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let tree = nest tree_of_val (depth - 1) (O.field obj i) ty in
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tree :: tree_list (i + 1) ty_list in
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tree_list start ty_list
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and tree_of_constr_with_args
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tree_of_cstr cstr_name inlined start depth obj ty_args =
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let lid = tree_of_cstr cstr_name in
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let args =
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if inlined then
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match ty_args with
|
|
| [ty] -> [ tree_of_val (depth - 1) obj ty ]
|
|
| _ -> assert false
|
|
else
|
|
tree_of_val_list start depth obj ty_args
|
|
in
|
|
Oval_constr (lid, args)
|
|
|
|
and tree_of_extension type_path depth bucket =
|
|
let slot =
|
|
if O.tag bucket <> 0 then bucket
|
|
else O.field bucket 0
|
|
in
|
|
let name = (O.obj(O.field slot 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_extension(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 slot (EVP.eval_path env path))
|
|
then raise Not_found;
|
|
tree_of_constr_with_args
|
|
(fun x -> Oide_ident x) name (cstr.cstr_inlined <> None)
|
|
1 depth bucket
|
|
cstr.cstr_args
|
|
with Not_found | EVP.Error ->
|
|
match check_depth depth bucket ty with
|
|
Some x -> x
|
|
| None when Path.same type_path Predef.path_exn->
|
|
outval_of_untyped_exception bucket
|
|
| None ->
|
|
Oval_stuff "<extension>"
|
|
|
|
and find_printer depth env ty =
|
|
let rec find = function
|
|
| [] -> raise Not_found
|
|
| (name, Simple (sch, printer)) :: remainder ->
|
|
if Ctype.moregeneral env false sch ty
|
|
then printer
|
|
else find remainder
|
|
| (name, Generic (path, fn)) :: remainder ->
|
|
begin match (Ctype.expand_head env ty).desc with
|
|
| Tconstr (p, args, _) when Path.same p path ->
|
|
begin try apply_generic_printer path (fn depth) args
|
|
with _ -> (fun obj -> out_exn path) end
|
|
| _ -> find remainder end in
|
|
find !printers
|
|
|
|
and apply_generic_printer path printer args =
|
|
match (printer, args) with
|
|
| (Zero fn, []) -> (fun (obj : O.t)-> try fn obj with _ -> out_exn path)
|
|
| (Succ fn, arg :: args) ->
|
|
let printer = fn (fun depth obj -> tree_of_val depth obj arg) in
|
|
apply_generic_printer path printer args
|
|
| _ ->
|
|
(fun obj ->
|
|
let printer ppf =
|
|
fprintf ppf "<internal error: incorrect arity for '%a'>"
|
|
Printtyp.path path in
|
|
Oval_printer printer)
|
|
|
|
|
|
in nest tree_of_val max_depth obj ty
|
|
|
|
end
|