src/Tools/subtyping.ML
author wenzelm
Fri, 29 Oct 2010 22:07:48 +0200
changeset 40283 805ce1d64af0
parent 40282 329cd9dd5949
child 40284 c9acf88447e6
permissions -rw-r--r--
proper signature constraint for ML structure; explicit theory setup, which is customary outside Pure; formal @{binding} instead of Binding.name;
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(*  Title:      Tools/subtyping.ML
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    Author:     Dmitriy Traytel, TU Muenchen
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Coercive subtyping via subtype constraints.
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*)
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signature SUBTYPING =
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sig
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  datatype variance = COVARIANT | CONTRAVARIANT | INVARIANT
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  val infer_types: Proof.context -> (string -> typ option) -> (indexname -> typ option) ->
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    term list -> term list
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  val setup: theory -> theory
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end;
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structure Subtyping: SUBTYPING =
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struct
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(** coercions data **)
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datatype variance = COVARIANT | CONTRAVARIANT | INVARIANT
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datatype data = Data of
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  {coes: term Symreltab.table,  (*coercions table*)
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   coes_graph: unit Graph.T,  (*coercions graph*)
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   tmaps: (term * variance list) Symtab.table};  (*map functions*)
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fun make_data (coes, coes_graph, tmaps) =
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  Data {coes = coes, coes_graph = coes_graph, tmaps = tmaps};
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structure Data = Generic_Data
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(
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  type T = data;
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  val empty = make_data (Symreltab.empty, Graph.empty, Symtab.empty);
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  val extend = I;
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  fun merge
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    (Data {coes = coes1, coes_graph = coes_graph1, tmaps = tmaps1},
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      Data {coes = coes2, coes_graph = coes_graph2, tmaps = tmaps2}) =
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    make_data (Symreltab.merge (op aconv) (coes1, coes2),
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      Graph.merge (op =) (coes_graph1, coes_graph2),
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      Symtab.merge (eq_pair (op aconv) (op =)) (tmaps1, tmaps2));
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);
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fun map_data f =
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  Data.map (fn Data {coes, coes_graph, tmaps} =>
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    make_data (f (coes, coes_graph, tmaps)));
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fun map_coes f =
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  map_data (fn (coes, coes_graph, tmaps) =>
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    (f coes, coes_graph, tmaps));
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fun map_coes_graph f =
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  map_data (fn (coes, coes_graph, tmaps) =>
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    (coes, f coes_graph, tmaps));
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fun map_coes_and_graph f =
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  map_data (fn (coes, coes_graph, tmaps) =>
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    let val (coes', coes_graph') = f (coes, coes_graph);
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    in (coes', coes_graph', tmaps) end);
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fun map_tmaps f =
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  map_data (fn (coes, coes_graph, tmaps) =>
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    (coes, coes_graph, f tmaps));
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fun rep_data context = Data.get context |> (fn Data args => args);
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val coes_of = #coes o rep_data;
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val coes_graph_of = #coes_graph o rep_data;
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val tmaps_of = #tmaps o rep_data;
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(** utils **)
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val is_param = Type_Infer.is_param
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val is_paramT = Type_Infer.is_paramT
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val deref = Type_Infer.deref
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fun mk_param i S = TVar (("?'a", i), S); (* TODO dup? see src/Pure/type_infer.ML *)
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fun nameT (Type (s, [])) = s;
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fun t_of s = Type (s, []);
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fun sort_of (TFree (_, S)) = SOME S
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  | sort_of (TVar (_, S)) = SOME S
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  | sort_of _ = NONE;
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val is_typeT = fn (Type _) => true | _ => false;
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val is_compT = fn (Type (_, _ :: _)) => true | _ => false;
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val is_freeT = fn (TFree _) => true | _ => false;
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val is_fixedvarT = fn (TVar (xi, _)) => not (is_param xi) | _ => false;
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(* unification *)  (* TODO dup? needed for weak unification *)
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exception NO_UNIFIER of string * typ Vartab.table;
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fun unify weak ctxt =
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  let
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    val thy = ProofContext.theory_of ctxt;
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    val pp = Syntax.pp ctxt;
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    val arity_sorts = Type.arity_sorts pp (Sign.tsig_of thy);
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    (* adjust sorts of parameters *)
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    fun not_of_sort x S' S =
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      "Variable " ^ x ^ "::" ^ Syntax.string_of_sort ctxt S' ^ " not of sort " ^
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        Syntax.string_of_sort ctxt S;
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    fun meet (_, []) tye_idx = tye_idx
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      | meet (Type (a, Ts), S) (tye_idx as (tye, _)) =
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          meets (Ts, arity_sorts a S handle ERROR msg => raise NO_UNIFIER (msg, tye)) tye_idx
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      | meet (TFree (x, S'), S) (tye_idx as (tye, _)) =
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          if Sign.subsort thy (S', S) then tye_idx
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          else raise NO_UNIFIER (not_of_sort x S' S, tye)
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      | meet (TVar (xi, S'), S) (tye_idx as (tye, idx)) =
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          if Sign.subsort thy (S', S) then tye_idx
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          else if Type_Infer.is_param xi then
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            (Vartab.update_new (xi, mk_param idx (Sign.inter_sort thy (S', S))) tye, idx + 1)
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          else raise NO_UNIFIER (not_of_sort (Term.string_of_vname xi) S' S, tye)
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    and meets (T :: Ts, S :: Ss) (tye_idx as (tye, _)) =
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          meets (Ts, Ss) (meet (deref tye T, S) tye_idx)
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      | meets _ tye_idx = tye_idx;
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    val weak_meet = if weak then fn _ => I else meet
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diff changeset
   125
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   126
    (* occurs check and assignment *)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   127
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   128
    fun occurs_check tye xi (TVar (xi', _)) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   129
          if xi = xi' then raise NO_UNIFIER ("Occurs check!", tye)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   130
          else
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   131
            (case Vartab.lookup tye xi' of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   132
              NONE => ()
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   133
            | SOME T => occurs_check tye xi T)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   134
      | occurs_check tye xi (Type (_, Ts)) = List.app (occurs_check tye xi) Ts
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   135
      | occurs_check _ _ _ = ();
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   136
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   137
    fun assign xi (T as TVar (xi', _)) S env =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   138
          if xi = xi' then env
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   139
          else env |> weak_meet (T, S) |>> Vartab.update_new (xi, T)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   140
      | assign xi T S (env as (tye, _)) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   141
          (occurs_check tye xi T; env |> weak_meet (T, S) |>> Vartab.update_new (xi, T));
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   142
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   143
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   144
    (* unification *)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   145
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   146
    fun show_tycon (a, Ts) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   147
      quote (Syntax.string_of_typ ctxt (Type (a, replicate (length Ts) dummyT)));
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   148
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   149
    fun unif (T1, T2) (env as (tye, _)) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   150
      (case pairself (`is_paramT o deref tye) (T1, T2) of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   151
        ((true, TVar (xi, S)), (_, T)) => assign xi T S env
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   152
      | ((_, T), (true, TVar (xi, S))) => assign xi T S env
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   153
      | ((_, Type (a, Ts)), (_, Type (b, Us))) =>
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   154
          if weak andalso null Ts andalso null Us then env
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   155
          else if a <> b then
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   156
            raise NO_UNIFIER
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   157
              ("Clash of types " ^ show_tycon (a, Ts) ^ " and " ^ show_tycon (b, Us), tye)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   158
          else fold unif (Ts ~~ Us) env
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   159
      | ((_, T), (_, U)) => if T = U then env else raise NO_UNIFIER ("", tye));
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   160
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   161
  in unif end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   162
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   163
val weak_unify = unify true;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   164
val strong_unify = unify false;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   165
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   166
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   167
(* Typ_Graph shortcuts *)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   168
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   169
val add_edge = Typ_Graph.add_edge_acyclic;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   170
fun get_preds G T = Typ_Graph.all_preds G [T];
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   171
fun get_succs G T = Typ_Graph.all_succs G [T];
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   172
fun maybe_new_typnode T G = perhaps (try (Typ_Graph.new_node (T, ()))) G;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   173
fun maybe_new_typnodes Ts G = fold maybe_new_typnode Ts G;
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   174
fun new_imm_preds G Ts =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   175
  subtract (op =) Ts (distinct (op =) (maps (Typ_Graph.imm_preds G) Ts));
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   176
fun new_imm_succs G Ts =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   177
  subtract op= Ts (distinct (op =) (maps (Typ_Graph.imm_succs G) Ts));
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   178
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   179
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   180
(* Graph shortcuts *)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   181
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   182
fun maybe_new_node s G = perhaps (try (Graph.new_node (s, ()))) G
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   183
fun maybe_new_nodes ss G = fold maybe_new_node ss G
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   184
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   185
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   186
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   187
(** error messages **)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   188
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   189
fun prep_output ctxt tye bs ts Ts =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   190
  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   191
    val (Ts_bTs', ts') = Type_Infer.finish ctxt tye (Ts @ map snd bs, ts);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   192
    val (Ts', Ts'') = chop (length Ts) Ts_bTs';
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   193
    fun prep t =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   194
      let val xs = rev (Term.variant_frees t (rev (map fst bs ~~ Ts'')))
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   195
      in Term.subst_bounds (map Syntax.mark_boundT xs, t) end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   196
  in (map prep ts', Ts') end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   197
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   198
fun err_loose i = error ("Loose bound variable: B." ^ string_of_int i);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   199
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   200
fun inf_failed msg =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   201
  "Subtype inference failed" ^ (if msg = "" then "" else ": " ^ msg) ^ "\n\n";
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   202
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   203
fun err_appl ctxt msg tye bs t T u U =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   204
  let val ([t', u'], [T', U']) = prep_output ctxt tye bs [t, u] [T, U]
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   205
  in error (inf_failed msg ^ Type.appl_error (Syntax.pp ctxt) t' T' u' U' ^ "\n") end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   206
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   207
fun err_subtype ctxt msg tye (bs, t $ u, U, V, U') =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   208
  err_appl ctxt msg tye bs t (U --> V) u U';
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   209
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   210
fun err_list ctxt msg tye Ts =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   211
  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   212
    val (_, Ts') = prep_output ctxt tye [] [] Ts;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   213
    val text = cat_lines ([inf_failed msg,
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   214
      "Cannot unify a list of types that should be the same,",
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   215
      "according to suptype dependencies:",
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   216
      (Pretty.string_of (Pretty.list "[" "]" (map (Pretty.typ (Syntax.pp ctxt)) Ts')))]);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   217
  in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   218
    error text
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   219
  end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   220
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   221
fun err_bound ctxt msg tye packs =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   222
  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   223
    val pp = Syntax.pp ctxt;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   224
    val (ts, Ts) = fold
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   225
      (fn (bs, t $ u, U, _, U') => fn (ts, Ts) =>
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   226
        let val (t', T') = prep_output ctxt tye bs [t, u] [U, U']
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   227
        in (t' :: ts, T' :: Ts) end)
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   228
      packs ([], []);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   229
    val text = cat_lines ([inf_failed msg, "Cannot fullfill subtype constraints:"] @
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   230
        (map2 (fn [t, u] => fn [T, U] => Pretty.string_of (
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   231
          Pretty.block [
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   232
            Pretty.typ pp T, Pretty.brk 2, Pretty.str "<:", Pretty.brk 2, Pretty.typ pp U,
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   233
            Pretty.brk 3, Pretty.str "from function application", Pretty.brk 2,
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   234
            Pretty.block [Pretty.term pp t, Pretty.brk 1, Pretty.term pp u]]))
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   235
        ts Ts))
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   236
  in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   237
    error text
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   238
  end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   239
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   240
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   241
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   242
(** constraint generation **)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   243
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   244
fun generate_constraints ctxt =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   245
  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   246
    fun gen cs _ (Const (_, T)) tye_idx = (T, tye_idx, cs)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   247
      | gen cs _ (Free (_, T)) tye_idx = (T, tye_idx, cs)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   248
      | gen cs _ (Var (_, T)) tye_idx = (T, tye_idx, cs)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   249
      | gen cs bs (Bound i) tye_idx =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   250
          (snd (nth bs i handle Subscript => err_loose i), tye_idx, cs)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   251
      | gen cs bs (Abs (x, T, t)) tye_idx =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   252
          let val (U, tye_idx', cs') = gen cs ((x, T) :: bs) t tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   253
          in (T --> U, tye_idx', cs') end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   254
      | gen cs bs (t $ u) tye_idx =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   255
          let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   256
            val (T, tye_idx', cs') = gen cs bs t tye_idx;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   257
            val (U', (tye, idx), cs'') = gen cs' bs u tye_idx';
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   258
            val U = mk_param idx [];
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   259
            val V = mk_param (idx + 1) [];
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   260
            val tye_idx''= strong_unify ctxt (U --> V, T) (tye, idx + 2)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   261
              handle NO_UNIFIER (msg, tye') => err_appl ctxt msg tye' bs t T u U;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   262
            val error_pack = (bs, t $ u, U, V, U');
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   263
          in (V, tye_idx'', ((U', U), error_pack) :: cs'') end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   264
  in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   265
    gen [] []
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   266
  end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   267
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   268
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   269
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   270
(** constraint resolution **)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   271
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   272
exception BOUND_ERROR of string;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   273
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   274
fun process_constraints ctxt cs tye_idx =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   275
  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   276
    val coes_graph = coes_graph_of (Context.Proof ctxt);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   277
    val tmaps = tmaps_of (Context.Proof ctxt);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   278
    val tsig = Sign.tsig_of (ProofContext.theory_of ctxt);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   279
    val pp = Syntax.pp ctxt;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   280
    val arity_sorts = Type.arity_sorts pp tsig;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   281
    val subsort = Type.subsort tsig;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   282
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   283
    fun split_cs _ [] = ([], [])
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   284
      | split_cs f (c :: cs) =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   285
          (case pairself f (fst c) of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   286
            (false, false) => apsnd (cons c) (split_cs f cs)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   287
          | _ => apfst (cons c) (split_cs f cs));
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   288
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   289
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   290
    (* check whether constraint simplification will terminate using weak unification *)
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   291
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   292
    val _ = fold (fn (TU, error_pack) => fn tye_idx =>
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   293
      (weak_unify ctxt TU tye_idx handle NO_UNIFIER (msg, tye) =>
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   294
        err_subtype ctxt ("Weak unification of subtype constraints fails:\n" ^ msg)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   295
          tye error_pack)) cs tye_idx;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   296
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   297
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   298
    (* simplify constraints *)
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   299
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   300
    fun simplify_constraints cs tye_idx =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   301
      let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   302
        fun contract a Ts Us error_pack done todo tye idx =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   303
          let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   304
            val arg_var =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   305
              (case Symtab.lookup tmaps a of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   306
                (*everything is invariant for unknown constructors*)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   307
                NONE => replicate (length Ts) INVARIANT
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   308
              | SOME av => snd av);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   309
            fun new_constraints (variance, constraint) (cs, tye_idx) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   310
              (case variance of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   311
                COVARIANT => (constraint :: cs, tye_idx)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   312
              | CONTRAVARIANT => (swap constraint :: cs, tye_idx)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   313
              | INVARIANT => (cs, strong_unify ctxt constraint tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   314
                  handle NO_UNIFIER (msg, tye) => err_subtype ctxt msg tye error_pack));
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   315
            val (new, (tye', idx')) = apfst (fn cs => (cs ~~ replicate (length cs) error_pack))
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   316
              (fold new_constraints (arg_var ~~ (Ts ~~ Us)) ([], (tye, idx)));
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   317
            val test_update = is_compT orf is_freeT orf is_fixedvarT;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   318
            val (ch, done') =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   319
              if not (null new) then ([],   done)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   320
              else split_cs (test_update o deref tye') done;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   321
            val todo' = ch @ todo;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   322
          in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   323
            simplify done' (new @ todo') (tye', idx')
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   324
          end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   325
        (*xi is definitely a parameter*)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   326
        and expand varleq xi S a Ts error_pack done todo tye idx =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   327
          let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   328
            val n = length Ts;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   329
            val args = map2 mk_param (idx upto idx + n - 1) (arity_sorts a S);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   330
            val tye' = Vartab.update_new (xi, Type(a, args)) tye;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   331
            val (ch, done') = split_cs (is_compT o deref tye') done;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   332
            val todo' = ch @ todo;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   333
            val new =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   334
              if varleq then (Type(a, args), Type (a, Ts))
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   335
              else (Type (a, Ts), Type(a, args));
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   336
          in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   337
            simplify done' ((new, error_pack) :: todo') (tye', idx + n)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   338
          end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   339
        (*TU is a pair of a parameter and a free/fixed variable*)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   340
        and eliminate TU error_pack done todo tye idx =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   341
          let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   342
            val [TVar (xi, S)] = filter is_paramT TU;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   343
            val [T] = filter_out is_paramT TU;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   344
            val SOME S' = sort_of T;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   345
            val test_update = if is_freeT T then is_freeT else is_fixedvarT;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   346
            val tye' = Vartab.update_new (xi, T) tye;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   347
            val (ch, done') = split_cs (test_update o deref tye') done;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   348
            val todo' = ch @ todo;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   349
          in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   350
            if subsort (S', S) (*TODO check this*)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   351
            then simplify done' todo' (tye', idx)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   352
            else err_subtype ctxt "Sort mismatch" tye error_pack
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   353
          end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   354
        and simplify done [] tye_idx = (done, tye_idx)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   355
          | simplify done (((T, U), error_pack) :: todo) (tye_idx as (tye, idx)) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   356
              (case (deref tye T, deref tye U) of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   357
                (Type (a, []), Type (b, [])) =>
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   358
                  if a = b then simplify done todo tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   359
                  else if Graph.is_edge coes_graph (a, b) then simplify done todo tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   360
                  else err_subtype ctxt (a ^" is not a subtype of " ^ b) (fst tye_idx) error_pack
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   361
              | (Type (a, Ts), Type (b, Us)) =>
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   362
                  if a<>b then err_subtype ctxt "Different constructors" (fst tye_idx) error_pack
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   363
                  else contract a Ts Us error_pack done todo tye idx
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   364
              | (TVar (xi, S), Type (a, Ts as (_ :: _))) =>
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   365
                  expand true xi S a Ts error_pack done todo tye idx
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   366
              | (Type (a, Ts as (_ :: _)), TVar (xi, S)) =>
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   367
                  expand false xi S a Ts error_pack done todo tye idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   368
              | (T, U) =>
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   369
                  if T = U then simplify done todo tye_idx
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   370
                  else if exists (is_freeT orf is_fixedvarT) [T, U] andalso
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   371
                    exists is_paramT [T, U]
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   372
                  then eliminate [T, U] error_pack done todo tye idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   373
                  else if exists (is_freeT orf is_fixedvarT) [T, U]
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   374
                  then err_subtype ctxt "Not eliminated free/fixed variables"
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   375
                        (fst tye_idx) error_pack
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   376
                  else simplify (((T, U), error_pack) :: done) todo tye_idx);
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   377
      in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   378
        simplify [] cs tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   379
      end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   380
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   381
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   382
    (* do simplification *)
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   383
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   384
    val (cs', tye_idx') = simplify_constraints cs tye_idx;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   385
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   386
    fun find_error_pack lower T' =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   387
      map snd (filter (fn ((T, U), _) => if lower then T' = U else T' = T) cs');
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   388
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   389
    fun unify_list (T :: Ts) tye_idx =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   390
      fold (fn U => fn tye_idx => strong_unify ctxt (T, U) tye_idx
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   391
        handle NO_UNIFIER (msg, tye) => err_list ctxt msg tye (T :: Ts))
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   392
      Ts tye_idx;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   393
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   394
    (*styps stands either for supertypes or for subtypes of a type T
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   395
      in terms of the subtype-relation (excluding T itself)*)
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   396
    fun styps super T =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   397
      (if super then Graph.imm_succs else Graph.imm_preds) coes_graph T
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   398
        handle Graph.UNDEF _ => [];
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   399
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   400
    fun minmax sup (T :: Ts) =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   401
      let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   402
        fun adjust T U = if sup then (T, U) else (U, T);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   403
        fun extract T [] = T
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   404
          | extract T (U :: Us) =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   405
              if Graph.is_edge coes_graph (adjust T U) then extract T Us
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   406
              else if Graph.is_edge coes_graph (adjust U T) then extract U Us
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   407
              else raise BOUND_ERROR "Uncomparable types in type list";
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   408
      in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   409
        t_of (extract T Ts)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   410
      end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   411
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   412
    fun ex_styp_of_sort super T styps_and_sorts =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   413
      let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   414
        fun adjust T U = if super then (T, U) else (U, T);
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   415
        fun styp_test U Ts = forall
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   416
          (fn T => T = U orelse Graph.is_edge coes_graph (adjust U T)) Ts;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   417
        fun fitting Ts S U = Type.of_sort tsig (t_of U, S) andalso styp_test U Ts
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   418
      in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   419
        forall (fn (Ts, S) => exists (fitting Ts S) (T :: styps super T)) styps_and_sorts
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   420
      end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   421
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   422
    (* computes the tightest possible, correct assignment for 'a::S
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   423
       e.g. in the supremum case (sup = true):
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   424
               ------- 'a::S---
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   425
              /        /    \  \
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   426
             /        /      \  \
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   427
        'b::C1   'c::C2 ...  T1 T2 ...
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   428
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   429
       sorts - list of sorts [C1, C2, ...]
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   430
       T::Ts - non-empty list of base types [T1, T2, ...]
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   431
    *)
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   432
    fun tightest sup S styps_and_sorts (T :: Ts) =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   433
      let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   434
        fun restriction T = Type.of_sort tsig (t_of T, S)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   435
          andalso ex_styp_of_sort (not sup) T styps_and_sorts;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   436
        fun candidates T = inter (op =) (filter restriction (T :: styps sup T));
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   437
      in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   438
        (case fold candidates Ts (filter restriction (T :: styps sup T)) of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   439
          [] => raise BOUND_ERROR ("No " ^ (if sup then "supremum" else "infimum"))
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   440
        | [T] => t_of T
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   441
        | Ts => minmax sup Ts)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   442
      end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   443
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   444
    fun build_graph G [] tye_idx = (G, tye_idx)
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   445
      | build_graph G ((T, U) :: cs) tye_idx =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   446
        if T = U then build_graph G cs tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   447
        else
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   448
          let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   449
            val G' = maybe_new_typnodes [T, U] G;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   450
            val (G'', tye_idx') = (add_edge (T, U) G', tye_idx)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   451
              handle Typ_Graph.CYCLES cycles =>
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   452
                let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   453
                  val (tye, idx) = fold unify_list cycles tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   454
                in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   455
                  (*all cycles collapse to one node,
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   456
                    because all of them share at least the nodes x and y*)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   457
                  collapse (tye, idx) (distinct (op =) (flat cycles)) G
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   458
                end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   459
          in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   460
            build_graph G'' cs tye_idx'
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   461
          end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   462
    and collapse (tye, idx) nodes G = (*nodes non-empty list*)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   463
      let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   464
        val T = hd nodes;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   465
        val P = new_imm_preds G nodes;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   466
        val S = new_imm_succs G nodes;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   467
        val G' = Typ_Graph.del_nodes (tl nodes) G;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   468
      in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   469
        build_graph G' (map (fn x => (x, T)) P @ map (fn x => (T, x)) S) (tye, idx)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   470
      end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   471
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   472
    fun assign_bound lower G key (tye_idx as (tye, _)) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   473
      if is_paramT (deref tye key) then
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   474
        let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   475
          val TVar (xi, S) = deref tye key;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   476
          val get_bound = if lower then get_preds else get_succs;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   477
          val raw_bound = get_bound G key;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   478
          val bound = map (deref tye) raw_bound;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   479
          val not_params = filter_out is_paramT bound;
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   480
          fun to_fulfil T =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   481
            (case sort_of T of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   482
              NONE => NONE
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   483
            | SOME S =>
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   484
                SOME (map nameT (filter_out is_paramT (map (deref tye) (get_bound G T))), S));
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   485
          val styps_and_sorts = distinct (op =) (map_filter to_fulfil raw_bound);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   486
          val assignment =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   487
            if null bound orelse null not_params then NONE
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   488
            else SOME (tightest lower S styps_and_sorts (map nameT not_params)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   489
                handle BOUND_ERROR msg => err_bound ctxt msg tye (find_error_pack lower key))
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   490
        in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   491
          (case assignment of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   492
            NONE => tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   493
          | SOME T =>
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   494
              if is_paramT T then tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   495
              else if lower then (*upper bound check*)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   496
                let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   497
                  val other_bound = map (deref tye) (get_succs G key);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   498
                  val s = nameT T;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   499
                in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   500
                  if subset (op = o apfst nameT) (filter is_typeT other_bound, s :: styps true s)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   501
                  then apfst (Vartab.update (xi, T)) tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   502
                  else err_bound ctxt ("Assigned simple type " ^ s ^
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   503
                    " clashes with the upper bound of variable " ^
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   504
                    Syntax.string_of_typ ctxt (TVar(xi, S))) tye (find_error_pack (not lower) key)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   505
                end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   506
              else apfst (Vartab.update (xi, T)) tye_idx)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   507
        end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   508
      else tye_idx;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   509
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   510
    val assign_lb = assign_bound true;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   511
    val assign_ub = assign_bound false;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   512
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   513
    fun assign_alternating ts' ts G tye_idx =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   514
      if ts' = ts then tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   515
      else
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   516
        let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   517
          val (tye_idx' as (tye, _)) = fold (assign_lb G) ts tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   518
            |> fold (assign_ub G) ts;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   519
        in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   520
          assign_alternating ts (filter (is_paramT o deref tye) ts) G tye_idx'
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   521
        end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   522
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   523
    (*Unify all weakly connected components of the constraint forest,
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   524
      that contain only params. These are the only WCCs that contain
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   525
      params anyway.*)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   526
    fun unify_params G (tye_idx as (tye, _)) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   527
      let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   528
        val max_params = filter (is_paramT o deref tye) (Typ_Graph.maximals G);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   529
        val to_unify = map (fn T => T :: get_preds G T) max_params;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   530
      in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   531
        fold unify_list to_unify tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   532
      end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   533
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   534
    fun solve_constraints G tye_idx = tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   535
      |> assign_alternating [] (Typ_Graph.keys G) G
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   536
      |> unify_params G;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   537
  in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   538
    build_graph Typ_Graph.empty (map fst cs') tye_idx'
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   539
      |-> solve_constraints
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   540
  end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   541
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   542
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   543
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   544
(** coercion insertion **)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   545
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   546
fun insert_coercions ctxt tye ts =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   547
  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   548
    fun deep_deref T =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   549
      (case deref tye T of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   550
        Type (a, Ts) => Type (a, map deep_deref Ts)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   551
      | U => U);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   552
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   553
    fun gen_coercion ((Type (a, [])), (Type (b, []))) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   554
          if a = b
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   555
          then Abs (Name.uu, Type (a, []), Bound 0)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   556
          else
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   557
            (case Symreltab.lookup (coes_of (Context.Proof ctxt)) (a, b) of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   558
              NONE => raise Fail (a ^ " is not a subtype of " ^ b)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   559
            | SOME co => co)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   560
      | gen_coercion ((Type (a, Ts)), (Type (b, Us))) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   561
          if a <> b
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   562
          then raise raise Fail ("Different constructors: " ^ a ^ " and " ^ b)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   563
          else
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   564
            let
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   565
              fun inst t Ts =
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   566
                Term.subst_vars
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   567
                  (((Term.add_tvar_namesT (fastype_of t) []) ~~ rev Ts), []) t;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   568
              fun sub_co (COVARIANT, TU) = gen_coercion TU
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   569
                | sub_co (CONTRAVARIANT, TU) = gen_coercion (swap TU);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   570
              fun ts_of [] = []
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   571
                | ts_of (Type ("fun", [x1, x2]) :: xs) = x1 :: x2 :: (ts_of xs);
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   572
            in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   573
              (case Symtab.lookup (tmaps_of (Context.Proof ctxt)) a of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   574
                NONE => raise Fail ("No map function for " ^ a ^ " known")
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   575
              | SOME tmap =>
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   576
                  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   577
                    val used_coes = map sub_co ((snd tmap) ~~ (Ts ~~ Us));
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   578
                  in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   579
                    Term.list_comb
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   580
                      (inst (fst tmap) (ts_of (map fastype_of used_coes)), used_coes)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   581
                  end)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   582
            end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   583
      | gen_coercion (T, U) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   584
          if Type.could_unify (T, U)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   585
          then Abs (Name.uu, T, Bound 0)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   586
          else raise Fail ("Cannot generate coercion from "
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   587
            ^ Syntax.string_of_typ ctxt T ^ " to " ^ Syntax.string_of_typ ctxt U);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   588
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   589
    fun insert _ (Const (c, T)) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   590
          let val T' = deep_deref T;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   591
          in (Const (c, T'), T') end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   592
      | insert _ (Free (x, T)) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   593
          let val T' = deep_deref T;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   594
          in (Free (x, T'), T') end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   595
      | insert _ (Var (xi, T)) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   596
          let val T' = deep_deref T;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   597
          in (Var (xi, T'), T') end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   598
      | insert bs (Bound i) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   599
          let val T = nth bs i handle Subscript =>
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   600
            raise TYPE ("Loose bound variable: B." ^ string_of_int i, [], []);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   601
          in (Bound i, T) end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   602
      | insert bs (Abs (x, T, t)) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   603
          let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   604
            val T' = deep_deref T;
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   605
            val (t', T'') = insert (T' :: bs) t;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   606
          in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   607
            (Abs (x, T', t'), T' --> T'')
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   608
          end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   609
      | insert bs (t $ u) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   610
          let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   611
            val (t', Type ("fun", [U, T])) = insert bs t;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   612
            val (u', U') = insert bs u;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   613
          in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   614
            if U <> U'
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   615
            then (t' $ (gen_coercion (U', U) $ u'), T)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   616
            else (t' $ u', T)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   617
          end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   618
  in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   619
    map (fst o insert []) ts
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   620
  end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   621
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   622
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   623
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   624
(** assembling the pipeline **)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   625
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   626
fun infer_types ctxt const_type var_type raw_ts =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   627
  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   628
    val (idx, ts) = Type_Infer.prepare ctxt const_type var_type raw_ts;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   629
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   630
    fun gen_all t (tye_idx, constraints) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   631
      let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   632
        val (_, tye_idx', constraints') = generate_constraints ctxt t tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   633
      in (tye_idx', constraints' @ constraints) end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   634
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   635
    val (tye_idx, constraints) = fold gen_all ts ((Vartab.empty, idx), []);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   636
    val (tye, _) = process_constraints ctxt constraints tye_idx;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   637
    val ts' = insert_coercions ctxt tye ts;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   638
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   639
    val (_, ts'') = Type_Infer.finish ctxt tye ([], ts');
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   640
  in ts'' end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   641
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   642
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   643
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   644
(** installation **)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   645
40283
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   646
(* term check *)
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   647
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   648
fun coercion_infer_types ctxt =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   649
  infer_types ctxt
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   650
    (try (Consts.the_constraint (ProofContext.consts_of ctxt)))
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   651
    (ProofContext.def_type ctxt);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   652
40283
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   653
val add_term_check =
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   654
  Syntax.add_term_check ~100 "coercions"
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   655
    (fn xs => fn ctxt =>
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   656
      let val xs' = coercion_infer_types ctxt xs
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   657
      in if eq_list (op aconv) (xs, xs') then NONE else SOME (xs', ctxt) end);
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   658
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   659
40283
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   660
(* declarations *)
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   661
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   662
fun add_type_map map_fun context =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   663
  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   664
    val ctxt = Context.proof_of context;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   665
    val t = singleton (Variable.polymorphic ctxt) (Syntax.read_term ctxt map_fun);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   666
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   667
    fun err_str () = "\n\nthe general type signature for a map function is" ^
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   668
      "\nf1 => f2 => ... => fn => C [x1, ..., xn] => C [x1, ..., xn]" ^
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   669
      "\nwhere C is a constructor and fi is of type (xi => yi) or (yi => xi)";
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   670
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   671
    fun gen_arg_var ([], []) = []
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   672
      | gen_arg_var ((T, T') :: Ts, (U, U') :: Us) =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   673
          if T = U andalso T' = U' then COVARIANT :: gen_arg_var (Ts, Us)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   674
          else if T = U' andalso T' = U then CONTRAVARIANT :: gen_arg_var (Ts, Us)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   675
          else error ("Functions do not apply to arguments correctly:" ^ err_str ())
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   676
      | gen_arg_var (_, _) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   677
          error ("Different numbers of functions and arguments\n" ^ err_str ());
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   678
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   679
    (* TODO: This function is only needed to introde the fun type map
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   680
      function: "% f g h . g o h o f". There must be a better solution. *)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   681
    fun balanced (Type (_, [])) (Type (_, [])) = true
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   682
      | balanced (Type (a, Ts)) (Type (b, Us)) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   683
          a = b andalso forall I (map2 balanced Ts Us)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   684
      | balanced (TFree _) (TFree _) = true
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   685
      | balanced (TVar _) (TVar _) = true
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   686
      | balanced _ _ = false;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   687
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   688
    fun check_map_fun (pairs, []) (Type ("fun", [T as Type (C, Ts), U as Type (_, Us)])) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   689
          if balanced T U
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   690
          then ((pairs, Ts ~~ Us), C)
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   691
          else if C = "fun"
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   692
            then check_map_fun (pairs @ [(hd Ts, hd (tl Ts))], []) U
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   693
            else error ("Not a proper map function:" ^ err_str ())
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   694
      | check_map_fun _ _ = error ("Not a proper map function:" ^ err_str ());
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   695
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   696
    val res = check_map_fun ([], []) (fastype_of t);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   697
    val res_av = gen_arg_var (fst res);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   698
  in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   699
    map_tmaps (Symtab.update (snd res, (t, res_av))) context
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   700
  end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   701
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   702
fun add_coercion coercion context =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   703
  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   704
    val ctxt = Context.proof_of context;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   705
    val t = singleton (Variable.polymorphic ctxt) (Syntax.read_term ctxt coercion);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   706
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   707
    fun err_coercion () = error ("Bad type for coercion " ^
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   708
        Syntax.string_of_term ctxt t ^ ":\n" ^
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   709
        Syntax.string_of_typ ctxt (fastype_of t));
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   710
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   711
    val (Type ("fun", [T1, T2])) = fastype_of t
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   712
      handle Bind => err_coercion ();
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   713
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   714
    val a =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   715
      (case T1 of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   716
        Type (x, []) => x
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   717
      | _ => err_coercion ());
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   718
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   719
    val b =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   720
      (case T2 of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   721
        Type (x, []) => x
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   722
      | _ => err_coercion ());
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   723
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   724
    fun coercion_data_update (tab, G) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   725
      let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   726
        val G' = maybe_new_nodes [a, b] G
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   727
        val G'' = Graph.add_edge_trans_acyclic (a, b) G'
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   728
          handle Graph.CYCLES _ => error (a ^ " is already a subtype of " ^ b ^
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   729
            "!\n\nCannot add coercion of type: " ^ a ^ " => " ^ b);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   730
        val new_edges =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   731
          flat (Graph.dest G'' |> map (fn (x, ys) => ys |> map_filter (fn y =>
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   732
            if Graph.is_edge G' (x, y) then NONE else SOME (x, y))));
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   733
        val G_and_new = Graph.add_edge (a, b) G';
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   734
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   735
        fun complex_coercion tab G (a, b) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   736
          let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   737
            val path = hd (Graph.irreducible_paths G (a, b))
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   738
            val path' = (fst (split_last path)) ~~ tl path
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   739
          in Abs (Name.uu, Type (a, []),
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   740
              fold (fn t => fn u => t $ u) (map (the o Symreltab.lookup tab) path') (Bound 0))
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   741
          end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   742
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   743
        val tab' = fold
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   744
          (fn pair => fn tab => Symreltab.update (pair, complex_coercion tab G_and_new pair) tab)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   745
          (filter (fn pair => pair <> (a, b)) new_edges)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   746
          (Symreltab.update ((a, b), t) tab);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   747
      in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   748
        (tab', G'')
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   749
      end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   750
  in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   751
    map_coes_and_graph coercion_data_update context
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   752
  end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   753
40283
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   754
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   755
(* theory setup *)
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   756
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   757
val setup =
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   758
  Context.theory_map add_term_check #>
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   759
  Attrib.setup @{binding coercion} (Scan.lift Parse.term >>
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   760
    (fn t => fn (context, thm) => (add_coercion t context, thm)))
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   761
    "declaration of new coercions" #>
40283
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   762
  Attrib.setup @{binding map_function} (Scan.lift Parse.term >>
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   763
    (fn t => fn (context, thm) => (add_type_map t context, thm)))
40283
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   764
    "declaration of new map functions";
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   765
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   766
end;