336 lines
11 KiB
OCaml
336 lines
11 KiB
OCaml
(***********************************************************************)
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(* *)
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(* OCaml *)
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(* *)
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(* Xavier Leroy, 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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(* $Id$ *)
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(* Substitutions *)
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open Misc
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open Path
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open Types
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open Btype
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type t =
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{ types: (Ident.t, Path.t) Tbl.t;
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modules: (Ident.t, Path.t) Tbl.t;
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modtypes: (Ident.t, module_type) Tbl.t;
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for_saving: bool }
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let identity =
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{ types = Tbl.empty; modules = Tbl.empty; modtypes = Tbl.empty;
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for_saving = false }
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let add_type id p s = { s with types = Tbl.add id p s.types }
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let add_module id p s = { s with modules = Tbl.add id p s.modules }
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let add_modtype id ty s = { s with modtypes = Tbl.add id ty s.modtypes }
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let for_saving s = { s with for_saving = true }
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let rec module_path s = function
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Pident id as p ->
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begin try Tbl.find id s.modules with Not_found -> p end
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| Pdot(p, n, pos) ->
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Pdot(module_path s p, n, pos)
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| Papply(p1, p2) ->
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Papply(module_path s p1, module_path s p2)
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let rec modtype_path s = function
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Pident id as p ->
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begin try
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match Tbl.find id s.modtypes with
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| Tmty_ident p -> p
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| _ -> fatal_error "Subst.modtype_path"
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with Not_found -> p end
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| Pdot(p, n, pos) ->
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Pdot(module_path s p, n, pos)
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| Papply(p1, p2) ->
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fatal_error "Subst.modtype_path"
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let type_path s = function
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Pident id as p ->
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begin try Tbl.find id s.types with Not_found -> p end
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| Pdot(p, n, pos) ->
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Pdot(module_path s p, n, pos)
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| Papply(p1, p2) ->
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fatal_error "Subst.type_path"
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(* Special type ids for saved signatures *)
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let new_id = ref (-1)
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let reset_for_saving () = new_id := -1
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let newpersty desc =
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decr new_id;
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{ desc = desc; level = generic_level; id = !new_id }
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(* Similar to [Ctype.nondep_type_rec]. *)
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let rec typexp s ty =
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let ty = repr ty in
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match ty.desc with
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Tvar _ | Tunivar _ as desc ->
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if s.for_saving || ty.id < 0 then
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let ty' =
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if s.for_saving then newpersty desc
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else newty2 ty.level desc
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in
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save_desc ty desc; ty.desc <- Tsubst ty'; ty'
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else ty
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| Tsubst ty ->
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ty
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(* cannot do it, since it would omit subsitution
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| Tvariant row when not (static_row row) ->
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ty
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*)
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| _ ->
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let desc = ty.desc in
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save_desc ty desc;
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(* Make a stub *)
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let ty' = if s.for_saving then newpersty (Tvar None) else newgenvar () in
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ty.desc <- Tsubst ty';
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ty'.desc <-
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begin match desc with
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| Tconstr(p, tl, abbrev) ->
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Tconstr(type_path s p, List.map (typexp s) tl, ref Mnil)
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| Tpackage(p, n, tl) ->
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Tpackage(modtype_path s p, n, List.map (typexp s) tl)
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| Tobject (t1, name) ->
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Tobject (typexp s t1,
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ref (match !name with
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None -> None
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| Some (p, tl) ->
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Some (type_path s p, List.map (typexp s) tl)))
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| Tvariant row ->
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let row = row_repr row in
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let more = repr row.row_more in
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(* We must substitute in a subtle way *)
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(* Tsubst takes a tuple containing the row var and the variant *)
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begin match more.desc with
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Tsubst {desc = Ttuple [_;ty2]} ->
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(* This variant type has been already copied *)
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ty.desc <- Tsubst ty2; (* avoid Tlink in the new type *)
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Tlink ty2
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| _ ->
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let dup =
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s.for_saving || more.level = generic_level || static_row row ||
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match more.desc with Tconstr _ -> true | _ -> false in
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(* Various cases for the row variable *)
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let more' =
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match more.desc with
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Tsubst ty -> ty
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| Tconstr _ | Tnil -> typexp s more
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| Tunivar _ | Tvar _ ->
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save_desc more more.desc;
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if s.for_saving then newpersty more.desc else
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if dup && is_Tvar more then newgenty more.desc else more
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| _ -> assert false
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in
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(* Register new type first for recursion *)
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more.desc <- Tsubst(newgenty(Ttuple[more';ty']));
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(* Return a new copy *)
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let row =
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copy_row (typexp s) true row (not dup) more' in
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match row.row_name with
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Some (p, tl) ->
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Tvariant {row with row_name = Some (type_path s p, tl)}
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| None ->
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Tvariant row
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end
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| Tfield(label, kind, t1, t2) when field_kind_repr kind = Fabsent ->
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Tlink (typexp s t2)
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| _ -> copy_type_desc (typexp s) desc
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end;
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ty'
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(*
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Always make a copy of the type. If this is not done, type levels
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might not be correct.
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*)
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let type_expr s ty =
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let ty' = typexp s ty in
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cleanup_types ();
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ty'
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let type_declaration s decl =
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let decl =
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{ type_params = List.map (typexp s) decl.type_params;
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type_arity = decl.type_arity;
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type_kind =
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begin match decl.type_kind with
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Type_abstract -> Type_abstract
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| Type_variant cstrs ->
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Type_variant
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(List.map
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(fun (n, args, ret_type) ->
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(n, List.map (typexp s) args, may_map (typexp s) ret_type))
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cstrs)
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| Type_record(lbls, rep) ->
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Type_record
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(List.map (fun (n, mut, arg) -> (n, mut, typexp s arg)) lbls,
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rep)
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end;
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type_manifest =
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begin
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match decl.type_manifest with
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None -> None
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| Some ty -> Some(typexp s ty)
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end;
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type_private = decl.type_private;
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type_variance = decl.type_variance;
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type_newtype_level = None;
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type_loc = if s.for_saving then Location.none else decl.type_loc;
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}
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in
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cleanup_types ();
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decl
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let class_signature s sign =
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{ cty_self = typexp s sign.cty_self;
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cty_vars =
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Vars.map (function (m, v, t) -> (m, v, typexp s t)) sign.cty_vars;
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cty_concr = sign.cty_concr;
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cty_inher =
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List.map (fun (p, tl) -> (type_path s p, List.map (typexp s) tl))
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sign.cty_inher
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}
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let rec class_type s =
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function
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Tcty_constr (p, tyl, cty) ->
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Tcty_constr (type_path s p, List.map (typexp s) tyl, class_type s cty)
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| Tcty_signature sign ->
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Tcty_signature (class_signature s sign)
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| Tcty_fun (l, ty, cty) ->
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Tcty_fun (l, typexp s ty, class_type s cty)
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let class_declaration s decl =
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let decl =
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{ cty_params = List.map (typexp s) decl.cty_params;
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cty_variance = decl.cty_variance;
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cty_type = class_type s decl.cty_type;
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cty_path = type_path s decl.cty_path;
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cty_new =
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begin match decl.cty_new with
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None -> None
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| Some ty -> Some (typexp s ty)
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end }
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in
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(* Do not clean up if saving: next is cltype_declaration *)
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if not s.for_saving then cleanup_types ();
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decl
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let cltype_declaration s decl =
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let decl =
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{ clty_params = List.map (typexp s) decl.clty_params;
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clty_variance = decl.clty_variance;
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clty_type = class_type s decl.clty_type;
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clty_path = type_path s decl.clty_path }
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in
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(* Do clean up even if saving: type_declaration may be recursive *)
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cleanup_types ();
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decl
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let class_type s cty =
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let cty = class_type s cty in
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cleanup_types ();
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cty
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let value_description s descr =
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{ val_type = type_expr s descr.val_type;
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val_kind = descr.val_kind;
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val_loc = if s.for_saving then Location.none else descr.val_loc;
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}
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let exception_declaration s descr =
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{ exn_args = List.map (type_expr s) descr.exn_args;
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exn_loc = if s.for_saving then Location.none else descr.exn_loc;
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}
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let rec rename_bound_idents s idents = function
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[] -> (List.rev idents, s)
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| Tsig_type(id, d, _) :: sg ->
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let id' = Ident.rename id in
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rename_bound_idents (add_type id (Pident id') s) (id' :: idents) sg
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| Tsig_module(id, mty, _) :: sg ->
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let id' = Ident.rename id in
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rename_bound_idents (add_module id (Pident id') s) (id' :: idents) sg
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| Tsig_modtype(id, d) :: sg ->
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let id' = Ident.rename id in
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rename_bound_idents (add_modtype id (Tmty_ident(Pident id')) s)
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(id' :: idents) sg
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| (Tsig_value(id, _) | Tsig_exception(id, _) |
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Tsig_class(id, _, _) | Tsig_cltype(id, _, _)) :: sg ->
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let id' = Ident.rename id in
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rename_bound_idents s (id' :: idents) sg
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let rec modtype s = function
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Tmty_ident p as mty ->
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begin match p with
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Pident id ->
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begin try Tbl.find id s.modtypes with Not_found -> mty end
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| Pdot(p, n, pos) ->
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Tmty_ident(Pdot(module_path s p, n, pos))
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| Papply(p1, p2) ->
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fatal_error "Subst.modtype"
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end
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| Tmty_signature sg ->
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Tmty_signature(signature s sg)
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| Tmty_functor(id, arg, res) ->
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let id' = Ident.rename id in
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Tmty_functor(id', modtype s arg,
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modtype (add_module id (Pident id') s) res)
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and signature s sg =
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(* Components of signature may be mutually recursive (e.g. type declarations
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or class and type declarations), so first build global renaming
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substitution... *)
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let (new_idents, s') = rename_bound_idents s [] sg in
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(* ... then apply it to each signature component in turn *)
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List.map2 (signature_component s') sg new_idents
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and signature_component s comp newid =
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match comp with
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Tsig_value(id, d) ->
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Tsig_value(newid, value_description s d)
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| Tsig_type(id, d, rs) ->
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Tsig_type(newid, type_declaration s d, rs)
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| Tsig_exception(id, d) ->
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Tsig_exception(newid, exception_declaration s d)
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| Tsig_module(id, mty, rs) ->
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Tsig_module(newid, modtype s mty, rs)
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| Tsig_modtype(id, d) ->
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Tsig_modtype(newid, modtype_declaration s d)
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| Tsig_class(id, d, rs) ->
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Tsig_class(newid, class_declaration s d, rs)
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| Tsig_cltype(id, d, rs) ->
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Tsig_cltype(newid, cltype_declaration s d, rs)
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and modtype_declaration s = function
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Tmodtype_abstract -> Tmodtype_abstract
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| Tmodtype_manifest mty -> Tmodtype_manifest(modtype s mty)
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(* For every binding k |-> d of m1, add k |-> f d to m2
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and return resulting merged map. *)
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let merge_tbls f m1 m2 =
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Tbl.fold (fun k d accu -> Tbl.add k (f d) accu) m1 m2
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(* Composition of substitutions:
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apply (compose s1 s2) x = apply s2 (apply s1 x) *)
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let compose s1 s2 =
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{ types = merge_tbls (type_path s2) s1.types s2.types;
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modules = merge_tbls (module_path s2) s1.modules s2.modules;
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modtypes = merge_tbls (modtype s2) s1.modtypes s2.modtypes;
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for_saving = false }
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