src/Tools/subtyping.ML
author traytel
Mon, 29 Nov 2010 16:53:08 +0100
changeset 40836 a81d66d72e70
parent 40297 c753e3f8b4d6
child 40838 d9bd6df700a8
permissions -rw-r--r--
two-staged architecture for subtyping; improved error messages of subtyping (using the new architecture); bugfix: constraint graph consistency check after cycle elimination;
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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 add_type_map: term -> Context.generic -> Context.generic
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  val add_coercion: term -> Context.generic -> Context.generic
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  val gen_coercion: Proof.context -> typ Vartab.table -> (typ * typ) -> term
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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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val rep_data = (fn Data args => args) o Data.get o Context.Proof;
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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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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 (Type_Infer.is_param xi) | _ => false;
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(* unification *)
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exception TYPE_INFERENCE_ERROR of unit -> string;
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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
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              (xi, Type_Infer.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 (Type_Infer.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
   126
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   127
    (* occurs check and assignment *)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   128
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   129
    fun occurs_check tye xi (TVar (xi', _)) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   130
          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
   131
          else
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   132
            (case Vartab.lookup tye xi' of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   133
              NONE => ()
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   134
            | SOME T => occurs_check tye xi T)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   135
      | 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
   136
      | occurs_check _ _ _ = ();
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   137
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   138
    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
   139
          if xi = xi' then env
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   140
          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
   141
      | assign xi T S (env as (tye, _)) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   142
          (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
   143
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   144
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   145
    (* unification *)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   146
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   147
    fun show_tycon (a, Ts) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   148
      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
   149
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   150
    fun unif (T1, T2) (env as (tye, _)) =
40286
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   151
      (case pairself (`Type_Infer.is_paramT o Type_Infer.deref tye) (T1, T2) of
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   152
        ((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
   153
      | ((_, 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
   154
      | ((_, Type (a, Ts)), (_, Type (b, Us))) =>
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   155
          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
   156
          else if a <> b then
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   157
            raise NO_UNIFIER
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   158
              ("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
   159
          else fold unif (Ts ~~ Us) env
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   160
      | ((_, 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
   161
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   162
  in unif end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   163
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   164
val weak_unify = unify true;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   165
val strong_unify = unify false;
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
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   168
(* Typ_Graph shortcuts *)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   169
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   170
val add_edge = Typ_Graph.add_edge_acyclic;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   171
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
   172
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
   173
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
   174
fun maybe_new_typnodes Ts G = fold maybe_new_typnode Ts G;
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   175
fun new_imm_preds G Ts =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   176
  subtract (op =) Ts (distinct (op =) (maps (Typ_Graph.imm_preds G) Ts));
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   177
fun new_imm_succs G Ts =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   178
  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
   179
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   180
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   181
(* Graph shortcuts *)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   182
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   183
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
   184
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
   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
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   188
(** error messages **)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   189
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   190
fun gen_msg err msg = 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   191
  err () ^ "\nNow trying to infer coercions:\n\nCoercion inference failed" ^ 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   192
  (if msg = "" then "" else ": " ^ msg) ^ "\n";
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   193
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   194
fun prep_output ctxt tye bs ts Ts =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   195
  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   196
    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
   197
    val (Ts', Ts'') = chop (length Ts) Ts_bTs';
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   198
    fun prep t =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   199
      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
   200
      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
   201
  in (map prep ts', Ts') end;
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_loose i = error ("Loose bound variable: B." ^ string_of_int i);
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   204
  
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   205
fun unif_failed msg =
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   206
  "Type unification failed" ^ (if msg = "" then "" else ": " ^ msg) ^ "\n\n";
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   207
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   208
fun subtyping_err_appl_msg ctxt msg tye bs t T u U () =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   209
  let val ([t', u'], [T', U']) = prep_output ctxt tye bs [t, u] [T, U]
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   210
  in msg ^ Type.appl_error (Syntax.pp ctxt) t' T' u' U' ^ "\n" end;
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   211
  
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   212
fun err_appl_msg ctxt msg tye bs t T u U () =
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   213
  let val ([t', u'], [T', U']) = prep_output ctxt tye bs [t, u] [T, U]
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   214
  in unif_failed msg ^ Type.appl_error (Syntax.pp ctxt) t' T' u' U' ^ "\n" end;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   215
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   216
fun err_list ctxt msg tye Ts =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   217
  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   218
    val (_, Ts') = prep_output ctxt tye [] [] Ts;
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   219
    val text = cat_lines ([msg,
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   220
      "Cannot unify a list of types that should be the same:",
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   221
      (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
   222
  in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   223
    error text
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   224
  end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   225
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   226
fun err_bound ctxt msg tye packs =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   227
  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   228
    val pp = Syntax.pp ctxt;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   229
    val (ts, Ts) = fold
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   230
      (fn (bs, t $ u, U, _, U') => fn (ts, Ts) =>
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   231
        let val (t', T') = prep_output ctxt tye bs [t, u] [U', U]
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   232
        in (t' :: ts, T' :: Ts) end)
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   233
      packs ([], []);
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   234
    val text = cat_lines ([msg, "Cannot fulfil subtype constraints:"] @
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   235
        (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
   236
          Pretty.block [
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   237
            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
   238
            Pretty.brk 3, Pretty.str "from function application", Pretty.brk 2,
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   239
            Pretty.block [Pretty.term pp (t $ u)]]))
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   240
        ts Ts))
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   241
  in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   242
    error text
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   243
  end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   244
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   245
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   246
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   247
(** constraint generation **)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   248
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   249
fun generate_constraints ctxt err =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   250
  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   251
    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
   252
      | 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
   253
      | 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
   254
      | gen cs bs (Bound i) tye_idx =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   255
          (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
   256
      | 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
   257
          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
   258
          in (T --> U, tye_idx', cs') end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   259
      | gen cs bs (t $ u) tye_idx =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   260
          let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   261
            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
   262
            val (U', (tye, idx), cs'') = gen cs' bs u tye_idx';
40286
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   263
            val U = Type_Infer.mk_param idx [];
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   264
            val V = Type_Infer.mk_param (idx + 1) [];
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   265
            val tye_idx''= strong_unify ctxt (U --> V, T) (tye, idx + 2)
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   266
              handle NO_UNIFIER (msg, tye') => error (gen_msg err msg);
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   267
            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
   268
          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
   269
  in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   270
    gen [] []
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   271
  end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   272
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
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   275
(** constraint resolution **)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   276
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   277
exception BOUND_ERROR of string;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   278
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   279
fun process_constraints ctxt err cs tye_idx =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   280
  let
40285
80136c4240cc simplified data lookup;
wenzelm
parents: 40284
diff changeset
   281
    val coes_graph = coes_graph_of ctxt;
80136c4240cc simplified data lookup;
wenzelm
parents: 40284
diff changeset
   282
    val tmaps = tmaps_of ctxt;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   283
    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
   284
    val pp = Syntax.pp ctxt;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   285
    val arity_sorts = Type.arity_sorts pp tsig;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   286
    val subsort = Type.subsort tsig;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   287
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   288
    fun split_cs _ [] = ([], [])
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   289
      | split_cs f (c :: cs) =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   290
          (case pairself f (fst c) of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   291
            (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
   292
          | _ => apfst (cons c) (split_cs f cs));
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   293
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   294
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   295
    (* check whether constraint simplification will terminate using weak unification *)
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   296
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   297
    val _ = fold (fn (TU, error_pack) => fn tye_idx =>
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   298
      weak_unify ctxt TU tye_idx handle NO_UNIFIER (msg, tye) =>
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   299
        error (gen_msg err ("weak unification of subtype constraints fails\n" ^ msg))) cs tye_idx;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   300
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   301
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   302
    (* simplify constraints *)
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   303
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   304
    fun simplify_constraints cs tye_idx =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   305
      let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   306
        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
   307
          let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   308
            val arg_var =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   309
              (case Symtab.lookup tmaps a of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   310
                (*everything is invariant for unknown constructors*)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   311
                NONE => replicate (length Ts) INVARIANT
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   312
              | SOME av => snd av);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   313
            fun new_constraints (variance, constraint) (cs, tye_idx) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   314
              (case variance of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   315
                COVARIANT => (constraint :: cs, tye_idx)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   316
              | CONTRAVARIANT => (swap constraint :: cs, tye_idx)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   317
              | INVARIANT => (cs, strong_unify ctxt constraint tye_idx
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   318
                  handle NO_UNIFIER (msg, tye) => 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   319
                    error (gen_msg err ("failed to unify invariant arguments\n" ^ msg))));
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   320
            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
   321
              (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
   322
            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
   323
            val (ch, done') =
40286
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   324
              if not (null new) then ([], done)
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   325
              else split_cs (test_update o Type_Infer.deref tye') done;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   326
            val todo' = ch @ todo;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   327
          in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   328
            simplify done' (new @ todo') (tye', idx')
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   329
          end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   330
        (*xi is definitely a parameter*)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   331
        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
   332
          let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   333
            val n = length Ts;
40286
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   334
            val args = map2 Type_Infer.mk_param (idx upto idx + n - 1) (arity_sorts a S);
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   335
            val tye' = Vartab.update_new (xi, Type(a, args)) tye;
40286
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   336
            val (ch, done') = split_cs (is_compT o Type_Infer.deref tye') done;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   337
            val todo' = ch @ todo;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   338
            val new =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   339
              if varleq then (Type(a, args), Type (a, Ts))
40286
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   340
              else (Type (a, Ts), Type (a, args));
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   341
          in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   342
            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
   343
          end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   344
        (*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
   345
        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
   346
          let
40286
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   347
            val [TVar (xi, S)] = filter Type_Infer.is_paramT TU;
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   348
            val [T] = filter_out Type_Infer.is_paramT TU;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   349
            val SOME S' = sort_of T;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   350
            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
   351
            val tye' = Vartab.update_new (xi, T) tye;
40286
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   352
            val (ch, done') = split_cs (test_update o Type_Infer.deref tye') done;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   353
            val todo' = ch @ todo;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   354
          in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   355
            if subsort (S', S) (*TODO check this*)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   356
            then simplify done' todo' (tye', idx)
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   357
            else error (gen_msg err "sort mismatch")
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   358
          end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   359
        and simplify done [] tye_idx = (done, tye_idx)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   360
          | simplify done (((T, U), error_pack) :: todo) (tye_idx as (tye, idx)) =
40286
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   361
              (case (Type_Infer.deref tye T, Type_Infer.deref tye U) of
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   362
                (Type (a, []), Type (b, [])) =>
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   363
                  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
   364
                  else if Graph.is_edge coes_graph (a, b) then simplify done todo tye_idx
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   365
                  else error (gen_msg err (a ^ " is not a subtype of " ^ b))
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   366
              | (Type (a, Ts), Type (b, Us)) =>
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   367
                  if a <> b then error (gen_msg err "different constructors")
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   368
                    (fst tye_idx) error_pack
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   369
                  else contract a Ts Us error_pack done todo tye idx
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   370
              | (TVar (xi, S), Type (a, Ts as (_ :: _))) =>
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   371
                  expand true xi S a Ts error_pack done todo tye idx
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   372
              | (Type (a, Ts as (_ :: _)), TVar (xi, S)) =>
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   373
                  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
   374
              | (T, U) =>
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   375
                  if T = U then simplify done todo tye_idx
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   376
                  else if exists (is_freeT orf is_fixedvarT) [T, U] andalso
40286
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   377
                    exists Type_Infer.is_paramT [T, U]
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   378
                  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
   379
                  else if exists (is_freeT orf is_fixedvarT) [T, U]
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   380
                  then error (gen_msg err "not eliminated free/fixed variables")
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   381
                  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
   382
      in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   383
        simplify [] cs tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   384
      end;
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
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   387
    (* do simplification *)
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   388
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   389
    val (cs', tye_idx') = simplify_constraints cs tye_idx;
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   390
    
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   391
    fun find_error_pack lower T' = map_filter 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   392
      (fn ((T, U), pack) => if if lower then T' = U else T' = T then SOME pack else NONE) cs';
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   393
      
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   394
    fun find_cycle_packs nodes = 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   395
      let
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   396
        val (but_last, last) = split_last nodes
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   397
        val pairs = (last, hd nodes) :: (but_last ~~ tl nodes);
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   398
      in
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   399
        map_filter
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   400
          (fn (TU, pack) => if member (eq_pair (op =) (op =)) pairs TU then SOME pack else NONE) 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   401
          cs'
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   402
      end;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   403
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   404
    fun unify_list (T :: Ts) tye_idx =
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   405
      fold (fn U => fn tye_idx' => strong_unify ctxt (T, U) tye_idx') Ts tye_idx;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   406
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   407
    (*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
   408
      in terms of the subtype-relation (excluding T itself)*)
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   409
    fun styps super T =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   410
      (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
   411
        handle Graph.UNDEF _ => [];
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   412
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   413
    fun minmax sup (T :: Ts) =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   414
      let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   415
        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
   416
        fun extract T [] = T
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   417
          | extract T (U :: Us) =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   418
              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
   419
              else if Graph.is_edge coes_graph (adjust U T) then extract U Us
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   420
              else raise BOUND_ERROR "uncomparable types in type list";
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   421
      in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   422
        t_of (extract T Ts)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   423
      end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   424
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   425
    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
   426
      let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   427
        fun adjust T U = if super then (T, U) else (U, T);
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   428
        fun styp_test U Ts = forall
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   429
          (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
   430
        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
   431
      in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   432
        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
   433
      end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   434
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   435
    (* 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
   436
       e.g. in the supremum case (sup = true):
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   437
               ------- 'a::S---
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   438
              /        /    \  \
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   439
             /        /      \  \
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   440
        'b::C1   'c::C2 ...  T1 T2 ...
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   441
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   442
       sorts - list of sorts [C1, C2, ...]
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   443
       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
   444
    *)
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   445
    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
   446
      let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   447
        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
   448
          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
   449
        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
   450
      in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   451
        (case fold candidates Ts (filter restriction (T :: styps sup T)) of
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   452
          [] => raise BOUND_ERROR ("no " ^ (if sup then "supremum" else "infimum"))
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   453
        | [T] => t_of T
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   454
        | Ts => minmax sup Ts)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   455
      end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   456
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   457
    fun build_graph G [] tye_idx = (G, tye_idx)
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   458
      | 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
   459
        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
   460
        else
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   461
          let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   462
            val G' = maybe_new_typnodes [T, U] G;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   463
            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
   464
              handle Typ_Graph.CYCLES cycles =>
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   465
                let
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   466
                  val (tye, idx) = 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   467
                    fold 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   468
                      (fn cycle => fn tye_idx' => (unify_list cycle tye_idx'
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   469
                        handle NO_UNIFIER (msg, tye) => 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   470
                          err_bound ctxt 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   471
                            (gen_msg err ("constraint cycle not unifiable" ^ msg)) (fst tye_idx)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   472
                            (find_cycle_packs cycle)))
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   473
                      cycles tye_idx
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   474
                in
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   475
                  collapse (tye, idx) cycles G
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   476
                end
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   477
          in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   478
            build_graph G'' cs tye_idx'
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   479
          end
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   480
    and collapse (tye, idx) cycles G = (*nodes non-empty list*)
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   481
      let
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   482
        (*all cycles collapse to one node,
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   483
          because all of them share at least the nodes x and y*)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   484
        val nodes = (distinct (op =) (flat cycles));
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   485
        val T = Type_Infer.deref tye (hd nodes);
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   486
        val P = new_imm_preds G nodes;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   487
        val S = new_imm_succs G nodes;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   488
        val G' = Typ_Graph.del_nodes (tl nodes) G;
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   489
        fun check_and_gen super T' =
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   490
          let val U = Type_Infer.deref tye T';
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   491
          in
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   492
            if not (is_typeT T) orelse not (is_typeT U) orelse T = U
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   493
            then if super then (hd nodes, T') else (T', hd nodes)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   494
            else 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   495
              if super andalso 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   496
                Graph.is_edge coes_graph (nameT T, nameT U) then (hd nodes, T')
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   497
              else if not super andalso 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   498
                Graph.is_edge coes_graph (nameT U, nameT T) then (T', hd nodes)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   499
              else err_bound ctxt (gen_msg err "cycle elimination produces inconsistent graph")
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   500
                    (fst tye_idx) 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   501
                    (maps find_cycle_packs cycles @ find_error_pack super T')
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   502
          end;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   503
      in
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   504
        build_graph G' (map (check_and_gen false) P @ map (check_and_gen true) S) (tye, idx)
40281
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
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   507
    fun assign_bound lower G key (tye_idx as (tye, _)) =
40286
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   508
      if Type_Infer.is_paramT (Type_Infer.deref tye key) then
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   509
        let
40286
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   510
          val TVar (xi, S) = Type_Infer.deref tye key;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   511
          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
   512
          val raw_bound = get_bound G key;
40286
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   513
          val bound = map (Type_Infer.deref tye) raw_bound;
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   514
          val not_params = filter_out Type_Infer.is_paramT bound;
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   515
          fun to_fulfil T =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   516
            (case sort_of T of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   517
              NONE => NONE
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   518
            | SOME S =>
40286
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   519
                SOME
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   520
                  (map nameT
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   521
                    (filter_out Type_Infer.is_paramT (map (Type_Infer.deref tye) (get_bound G T))),
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   522
                      S));
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   523
          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
   524
          val assignment =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   525
            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
   526
            else SOME (tightest lower S styps_and_sorts (map nameT not_params)
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   527
                handle BOUND_ERROR msg => 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   528
                  err_bound ctxt (gen_msg err msg) tye (find_error_pack lower key))
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   529
        in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   530
          (case assignment of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   531
            NONE => tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   532
          | SOME T =>
40286
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   533
              if Type_Infer.is_paramT T then tye_idx
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   534
              else if lower then (*upper bound check*)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   535
                let
40286
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   536
                  val other_bound = map (Type_Infer.deref tye) (get_succs G key);
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   537
                  val s = nameT T;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   538
                in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   539
                  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
   540
                  then apfst (Vartab.update (xi, T)) tye_idx
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   541
                  else err_bound ctxt (gen_msg err ("assigned simple type " ^ s ^
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   542
                    " clashes with the upper bound of variable " ^
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   543
                    Syntax.string_of_typ ctxt (TVar(xi, S)))) tye (find_error_pack (not lower) key)
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   544
                end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   545
              else apfst (Vartab.update (xi, T)) tye_idx)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   546
        end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   547
      else tye_idx;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   548
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   549
    val assign_lb = assign_bound true;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   550
    val assign_ub = assign_bound false;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   551
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   552
    fun assign_alternating ts' ts G tye_idx =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   553
      if ts' = ts then tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   554
      else
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   555
        let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   556
          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
   557
            |> fold (assign_ub G) ts;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   558
        in
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   559
          assign_alternating ts 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   560
            (filter (Type_Infer.is_paramT o Type_Infer.deref tye) ts) G tye_idx'
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   561
        end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   562
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   563
    (*Unify all weakly connected components of the constraint forest,
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   564
      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
   565
      params anyway.*)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   566
    fun unify_params G (tye_idx as (tye, _)) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   567
      let
40286
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   568
        val max_params =
b928e3960446 more sharing of operations, without aliases;
wenzelm
parents: 40285
diff changeset
   569
          filter (Type_Infer.is_paramT o Type_Infer.deref tye) (Typ_Graph.maximals G);
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   570
        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
   571
      in
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   572
        fold 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   573
          (fn Ts => fn tye_idx' => unify_list Ts tye_idx'
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   574
            handle NO_UNIFIER (msg, tye) => err_list ctxt (gen_msg err msg) (fst tye_idx) Ts)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   575
          to_unify tye_idx
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   576
      end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   577
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   578
    fun solve_constraints G tye_idx = tye_idx
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   579
      |> assign_alternating [] (Typ_Graph.keys G) G
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   580
      |> unify_params G;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   581
  in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   582
    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
   583
      |-> solve_constraints
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   584
  end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   585
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   586
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   587
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   588
(** coercion insertion **)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   589
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   590
fun gen_coercion ctxt tye (T1, T2) =
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   591
  (case pairself (Type_Infer.deref tye) (T1, T2) of
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   592
    ((Type (a, [])), (Type (b, []))) =>
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   593
        if a = b
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   594
        then Abs (Name.uu, Type (a, []), Bound 0)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   595
        else
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   596
          (case Symreltab.lookup (coes_of ctxt) (a, b) of
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   597
            NONE => raise Fail (a ^ " is not a subtype of " ^ b)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   598
          | SOME co => co)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   599
  | ((Type (a, Ts)), (Type (b, Us))) =>
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   600
        if a <> b
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   601
        then raise Fail ("Different constructors: " ^ a ^ " and " ^ b)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   602
        else
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   603
          let
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   604
            fun inst t Ts =
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   605
              Term.subst_vars
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   606
                (((Term.add_tvar_namesT (fastype_of t) []) ~~ rev Ts), []) t;
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   607
            fun sub_co (COVARIANT, TU) = gen_coercion ctxt tye TU
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   608
              | sub_co (CONTRAVARIANT, TU) = gen_coercion ctxt tye (swap TU);
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   609
            fun ts_of [] = []
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   610
              | ts_of (Type ("fun", [x1, x2]) :: xs) = x1 :: x2 :: (ts_of xs);
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   611
          in
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   612
            (case Symtab.lookup (tmaps_of ctxt) a of
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   613
              NONE => raise Fail ("No map function for " ^ a ^ " known")
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   614
            | SOME tmap =>
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   615
                let
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   616
                  val used_coes = map sub_co ((snd tmap) ~~ (Ts ~~ Us));
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   617
                in
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   618
                  Term.list_comb
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   619
                    (inst (fst tmap) (ts_of (map fastype_of used_coes)), used_coes)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   620
                end)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   621
          end
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   622
  | (T, U) =>
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   623
        if Type.could_unify (T, U)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   624
        then Abs (Name.uu, T, Bound 0)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   625
        else raise Fail ("Cannot generate coercion from "
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   626
          ^ Syntax.string_of_typ ctxt T ^ " to " ^ Syntax.string_of_typ ctxt U));
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   627
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   628
fun insert_coercions ctxt tye ts =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   629
  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   630
    fun insert _ (Const (c, T)) =
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   631
          let val T' = T;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   632
          in (Const (c, T'), T') end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   633
      | insert _ (Free (x, T)) =
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   634
          let val T' = T;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   635
          in (Free (x, T'), T') end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   636
      | insert _ (Var (xi, T)) =
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   637
          let val T' = T;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   638
          in (Var (xi, T'), T') end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   639
      | insert bs (Bound i) =
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   640
          let val T = nth bs i handle Subscript => err_loose i;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   641
          in (Bound i, T) end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   642
      | insert bs (Abs (x, T, t)) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   643
          let
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   644
            val T' = T;
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   645
            val (t', T'') = insert (T' :: bs) t;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   646
          in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   647
            (Abs (x, T', t'), T' --> T'')
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   648
          end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   649
      | insert bs (t $ u) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   650
          let
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   651
            val (t', Type ("fun", [U, T])) = apsnd (Type_Infer.deref tye) (insert bs t);
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   652
            val (u', U') = insert bs u;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   653
          in
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   654
            if can (fn TU => strong_unify ctxt TU (tye, 0)) (U, U')
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   655
            then (t' $ u', T)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   656
            else (t' $ (gen_coercion ctxt tye (U', U) $ u'), T)
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   657
          end
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   658
  in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   659
    map (fst o insert []) ts
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   660
  end;
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
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   663
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   664
(** assembling the pipeline **)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   665
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   666
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
   667
  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   668
    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
   669
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   670
    fun inf _ (t as (Const (_, T))) tye_idx = (t, T, tye_idx)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   671
      | inf _ (t as (Free (_, T))) tye_idx = (t, T, tye_idx)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   672
      | inf _ (t as (Var (_, T))) tye_idx = (t, T, tye_idx)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   673
      | inf bs (t as (Bound i)) tye_idx =
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   674
          (t, snd (nth bs i handle Subscript => err_loose i), tye_idx)
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   675
      | inf bs (Abs (x, T, t)) tye_idx =
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   676
          let val (t', U, tye_idx') = inf ((x, T) :: bs) t tye_idx
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   677
          in (Abs (x, T, t'), T --> U, tye_idx') end
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   678
      | inf bs (t $ u) tye_idx =
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   679
          let
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   680
            val (t', T, tye_idx') = inf bs t tye_idx;
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   681
            val (u', U, (tye, idx)) = inf bs u tye_idx';
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   682
            val V = Type_Infer.mk_param idx [];
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   683
            val (tu, tye_idx'') = (t' $ u', strong_unify ctxt (U --> V, T) (tye, idx + 1))
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   684
              handle NO_UNIFIER (msg, tye') => 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   685
                raise TYPE_INFERENCE_ERROR (err_appl_msg ctxt msg tye' bs t T u U);
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   686
          in (tu, V, tye_idx'') end;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   687
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   688
    fun infer_single t (ts, tye_idx) = 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   689
      let val (t, _, tye_idx') = inf [] t tye_idx;
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   690
      in (ts @ [t], tye_idx') end;
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   691
      
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   692
    val (ts', (tye, _)) = (fold infer_single ts ([], (Vartab.empty, idx))
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   693
      handle TYPE_INFERENCE_ERROR err =>     
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   694
        let
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   695
          fun gen_single t (tye_idx, constraints) =
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   696
            let val (_, tye_idx', constraints') = generate_constraints ctxt err t tye_idx
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   697
            in (tye_idx', constraints' @ constraints) end;
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   698
      
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   699
          val (tye_idx, constraints) = fold gen_single ts ((Vartab.empty, idx), []);
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   700
          val (tye, idx) = process_constraints ctxt err constraints tye_idx;
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   701
        in 
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   702
          (insert_coercions ctxt tye ts, (tye, idx))
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   703
        end);
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   704
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   705
    val (_, ts'') = Type_Infer.finish ctxt tye ([], ts');
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   706
  in ts'' end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   707
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   708
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   709
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   710
(** installation **)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   711
40283
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   712
(* term check *)
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   713
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   714
fun coercion_infer_types ctxt =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   715
  infer_types ctxt
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   716
    (try (Consts.the_constraint (ProofContext.consts_of ctxt)))
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   717
    (ProofContext.def_type ctxt);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   718
40283
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   719
val add_term_check =
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   720
  Syntax.add_term_check ~100 "coercions"
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   721
    (fn xs => fn ctxt =>
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   722
      let val xs' = coercion_infer_types ctxt xs
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   723
      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
   724
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   725
40283
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   726
(* declarations *)
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   727
40284
c9acf88447e6 export declarations by default, to allow other ML packages by-pass concrete syntax;
wenzelm
parents: 40283
diff changeset
   728
fun add_type_map raw_t context =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   729
  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   730
    val ctxt = Context.proof_of context;
40284
c9acf88447e6 export declarations by default, to allow other ML packages by-pass concrete syntax;
wenzelm
parents: 40283
diff changeset
   731
    val t = singleton (Variable.polymorphic ctxt) raw_t;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   732
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   733
    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
   734
      "\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
   735
      "\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
   736
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   737
    fun gen_arg_var ([], []) = []
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   738
      | 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
   739
          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
   740
          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
   741
          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
   742
      | gen_arg_var (_, _) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   743
          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
   744
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   745
    (* 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
   746
      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
   747
    fun balanced (Type (_, [])) (Type (_, [])) = true
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   748
      | balanced (Type (a, Ts)) (Type (b, Us)) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   749
          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
   750
      | balanced (TFree _) (TFree _) = true
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   751
      | balanced (TVar _) (TVar _) = true
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   752
      | balanced _ _ = false;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   753
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   754
    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
   755
          if balanced T U
40282
329cd9dd5949 proper header;
wenzelm
parents: 40281
diff changeset
   756
          then ((pairs, Ts ~~ Us), C)
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   757
          else if C = "fun"
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   758
            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
   759
            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
   760
      | 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
   761
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   762
    val res = check_map_fun ([], []) (fastype_of t);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   763
    val res_av = gen_arg_var (fst res);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   764
  in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   765
    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
   766
  end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   767
40284
c9acf88447e6 export declarations by default, to allow other ML packages by-pass concrete syntax;
wenzelm
parents: 40283
diff changeset
   768
fun add_coercion raw_t context =
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   769
  let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   770
    val ctxt = Context.proof_of context;
40284
c9acf88447e6 export declarations by default, to allow other ML packages by-pass concrete syntax;
wenzelm
parents: 40283
diff changeset
   771
    val t = singleton (Variable.polymorphic ctxt) raw_t;
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   772
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   773
    fun err_coercion () = error ("Bad type for coercion " ^
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   774
        Syntax.string_of_term ctxt t ^ ":\n" ^
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   775
        Syntax.string_of_typ ctxt (fastype_of t));
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   776
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   777
    val (Type ("fun", [T1, T2])) = fastype_of t
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   778
      handle Bind => err_coercion ();
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   779
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   780
    val a =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   781
      (case T1 of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   782
        Type (x, []) => x
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   783
      | _ => err_coercion ());
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   784
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   785
    val b =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   786
      (case T2 of
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   787
        Type (x, []) => x
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   788
      | _ => err_coercion ());
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   789
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   790
    fun coercion_data_update (tab, G) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   791
      let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   792
        val G' = maybe_new_nodes [a, b] G
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   793
        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
   794
          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
   795
            "!\n\nCannot add coercion of type: " ^ a ^ " => " ^ b);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   796
        val new_edges =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   797
          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
   798
            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
   799
        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
   800
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   801
        fun complex_coercion tab G (a, b) =
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   802
          let
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   803
            val path = hd (Graph.irreducible_paths G (a, b))
40836
a81d66d72e70 two-staged architecture for subtyping;
traytel
parents: 40297
diff changeset
   804
            val path' = fst (split_last path) ~~ tl path
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   805
          in Abs (Name.uu, Type (a, []),
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   806
              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
   807
          end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   808
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   809
        val tab' = fold
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   810
          (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
   811
          (filter (fn pair => pair <> (a, b)) new_edges)
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   812
          (Symreltab.update ((a, b), t) tab);
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   813
      in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   814
        (tab', G'')
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   815
      end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   816
  in
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   817
    map_coes_and_graph coercion_data_update context
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   818
  end;
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   819
40283
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   820
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   821
(* theory setup *)
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   822
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   823
val setup =
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   824
  Context.theory_map add_term_check #>
40284
c9acf88447e6 export declarations by default, to allow other ML packages by-pass concrete syntax;
wenzelm
parents: 40283
diff changeset
   825
  Attrib.setup @{binding coercion}
c9acf88447e6 export declarations by default, to allow other ML packages by-pass concrete syntax;
wenzelm
parents: 40283
diff changeset
   826
    (Args.term >> (fn t => Thm.declaration_attribute (K (add_coercion t))))
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   827
    "declaration of new coercions" #>
40297
c753e3f8b4d6 Attribute map_function -> coercion_map;
traytel
parents: 40286
diff changeset
   828
  Attrib.setup @{binding coercion_map}
40284
c9acf88447e6 export declarations by default, to allow other ML packages by-pass concrete syntax;
wenzelm
parents: 40283
diff changeset
   829
    (Args.term >> (fn t => Thm.declaration_attribute (K (add_type_map t))))
40283
805ce1d64af0 proper signature constraint for ML structure;
wenzelm
parents: 40282
diff changeset
   830
    "declaration of new map functions";
40281
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   831
3c6198fd0937 Coercive subtyping via subtype constraints, by Dmitriy Traytel (21-Oct-2010).
wenzelm
parents:
diff changeset
   832
end;