src/Pure/variable.ML
author wenzelm
Tue Jul 25 21:18:05 2006 +0200 (2006-07-25)
changeset 20198 7b385487f22f
parent 20162 d4bcb27686f9
child 20220 5dc68e9ecd9a
permissions -rw-r--r--
tuned;
wenzelm@19899
     1
(*  Title:      Pure/variable.ML
wenzelm@19899
     2
    ID:         $Id$
wenzelm@19899
     3
    Author:     Makarius
wenzelm@19899
     4
wenzelm@19899
     5
Fixed type/term variables and polymorphic term abbreviations.
wenzelm@19899
     6
*)
wenzelm@19899
     7
wenzelm@19899
     8
signature VARIABLE =
wenzelm@19899
     9
sig
wenzelm@19899
    10
  val is_body: Context.proof -> bool
wenzelm@19899
    11
  val set_body: bool -> Context.proof -> Context.proof
wenzelm@19899
    12
  val restore_body: Context.proof -> Context.proof -> Context.proof
wenzelm@20162
    13
  val names_of: Context.proof -> Name.context
wenzelm@19899
    14
  val fixes_of: Context.proof -> (string * string) list
wenzelm@19899
    15
  val binds_of: Context.proof -> (typ * term) Vartab.table
wenzelm@20162
    16
  val constraints_of: Context.proof -> typ Vartab.table * sort Vartab.table
wenzelm@19899
    17
  val is_declared: Context.proof -> string -> bool
wenzelm@19899
    18
  val is_fixed: Context.proof -> string -> bool
wenzelm@20149
    19
  val newly_fixed: Context.proof -> Context.proof -> string -> bool
wenzelm@20162
    20
  val default_type: Context.proof -> string -> typ option
wenzelm@19899
    21
  val def_type: Context.proof -> bool -> indexname -> typ option
wenzelm@20162
    22
  val def_sort: Context.proof -> indexname -> sort option
wenzelm@20162
    23
  val declare_constraints: term -> Context.proof -> Context.proof
wenzelm@20162
    24
  val declare_internal: term -> Context.proof -> Context.proof
wenzelm@19899
    25
  val declare_term: term -> Context.proof -> Context.proof
wenzelm@19926
    26
  val declare_thm: thm -> Context.proof -> Context.proof
wenzelm@19926
    27
  val thm_context: thm -> Context.proof
wenzelm@20162
    28
  val variant_frees: Context.proof -> term list -> (string * 'a) list -> (string * 'a) list
wenzelm@19911
    29
  val add_fixes: string list -> Context.proof -> string list * Context.proof
wenzelm@19911
    30
  val invent_fixes: string list -> Context.proof -> string list * Context.proof
wenzelm@19899
    31
  val invent_types: sort list -> Context.proof -> (string * sort) list * Context.proof
wenzelm@19911
    32
  val export_inst: Context.proof -> Context.proof -> string list * string list
wenzelm@19911
    33
  val exportT_inst: Context.proof -> Context.proof -> string list
wenzelm@19911
    34
  val export_terms: Context.proof -> Context.proof -> term list -> term list
wenzelm@19911
    35
  val exportT_terms: Context.proof -> Context.proof -> term list -> term list
wenzelm@19911
    36
  val exportT: Context.proof -> Context.proof -> thm list -> thm list
wenzelm@19911
    37
  val export: Context.proof -> Context.proof -> thm list -> thm list
wenzelm@19911
    38
  val importT_inst: term list -> Context.proof -> ((indexname * sort) * typ) list * Context.proof
wenzelm@19911
    39
  val import_inst: bool -> term list -> Context.proof ->
wenzelm@19911
    40
    (((indexname * sort) * typ) list * ((indexname * typ) * term) list) * Context.proof
wenzelm@19911
    41
  val importT_terms: term list -> Context.proof -> term list * Context.proof
wenzelm@19911
    42
  val import_terms: bool -> term list -> Context.proof -> term list * Context.proof
wenzelm@19911
    43
  val importT: thm list -> Context.proof -> thm list * Context.proof
wenzelm@19911
    44
  val import: bool -> thm list -> Context.proof -> thm list * Context.proof
wenzelm@19926
    45
  val tradeT: Context.proof -> (thm list -> thm list) -> thm list -> thm list
wenzelm@19926
    46
  val trade: Context.proof -> (thm list -> thm list) -> thm list -> thm list
wenzelm@20149
    47
  val focus: cterm -> Context.proof -> ((string * typ) list * cterm) * Context.proof
wenzelm@19899
    48
  val warn_extra_tfrees: Context.proof -> Context.proof -> unit
wenzelm@19899
    49
  val polymorphic: Context.proof -> term list -> term list
wenzelm@19899
    50
  val hidden_polymorphism: term -> typ -> (indexname * sort) list
wenzelm@19899
    51
  val add_binds: (indexname * term option) list -> Context.proof -> Context.proof
wenzelm@19899
    52
  val expand_binds: Context.proof -> term -> term
wenzelm@19899
    53
end;
wenzelm@19899
    54
wenzelm@19899
    55
structure Variable: VARIABLE =
wenzelm@19899
    56
struct
wenzelm@19899
    57
wenzelm@19899
    58
(** local context data **)
wenzelm@19899
    59
wenzelm@19899
    60
datatype data = Data of
wenzelm@20102
    61
 {is_body: bool,                        (*inner body mode*)
wenzelm@20162
    62
  names: Name.context,                  (*type/term variable names*)
wenzelm@20162
    63
  fixes: (string * string) list,        (*term fixes -- extern/intern*)
wenzelm@20102
    64
  binds: (typ * term) Vartab.table,     (*term bindings*)
wenzelm@20162
    65
  type_occs: string list Symtab.table,  (*type variables -- possibly within term variables*)
wenzelm@20162
    66
  constraints:
wenzelm@20102
    67
    typ Vartab.table *                  (*type constraints*)
wenzelm@20162
    68
    sort Vartab.table};                 (*default sorts*)
wenzelm@19899
    69
wenzelm@20162
    70
fun make_data (is_body, names, fixes, binds, type_occs, constraints) =
wenzelm@20162
    71
  Data {is_body = is_body, names = names, fixes = fixes, binds = binds,
wenzelm@20162
    72
    type_occs = type_occs, constraints = constraints};
wenzelm@19899
    73
wenzelm@19899
    74
structure Data = ProofDataFun
wenzelm@19899
    75
(
wenzelm@19899
    76
  val name = "Pure/variable";
wenzelm@19899
    77
  type T = data;
wenzelm@19899
    78
  fun init thy =
wenzelm@20162
    79
    make_data (false, Name.context, [], Vartab.empty, Symtab.empty, (Vartab.empty, Vartab.empty));
wenzelm@19899
    80
  fun print _ _ = ();
wenzelm@19899
    81
);
wenzelm@19899
    82
wenzelm@19899
    83
val _ = Context.add_setup Data.init;
wenzelm@19899
    84
wenzelm@19899
    85
fun map_data f =
wenzelm@20162
    86
  Data.map (fn Data {is_body, names, fixes, binds, type_occs, constraints} =>
wenzelm@20162
    87
    make_data (f (is_body, names, fixes, binds, type_occs, constraints)));
wenzelm@19899
    88
wenzelm@20162
    89
fun map_names f = map_data (fn (is_body, names, fixes, binds, type_occs, constraints) =>
wenzelm@20162
    90
  (is_body, f names, fixes, binds, type_occs, constraints));
wenzelm@20162
    91
wenzelm@20162
    92
fun map_fixes f = map_data (fn (is_body, names, fixes, binds, type_occs, constraints) =>
wenzelm@20162
    93
  (is_body, names, f fixes, binds, type_occs, constraints));
wenzelm@19899
    94
wenzelm@20162
    95
fun map_binds f = map_data (fn (is_body, names, fixes, binds, type_occs, constraints) =>
wenzelm@20162
    96
  (is_body, names, fixes, f binds, type_occs, constraints));
wenzelm@19899
    97
wenzelm@20162
    98
fun map_type_occs f = map_data (fn (is_body, names, fixes, binds, type_occs, constraints) =>
wenzelm@20162
    99
  (is_body, names, fixes, binds, f type_occs, constraints));
wenzelm@20102
   100
wenzelm@20162
   101
fun map_constraints f = map_data (fn (is_body, names, fixes, binds, type_occs, constraints) =>
wenzelm@20162
   102
  (is_body, names, fixes, binds, type_occs, f constraints));
wenzelm@19899
   103
wenzelm@19899
   104
fun rep_data ctxt = Data.get ctxt |> (fn Data args => args);
wenzelm@19899
   105
wenzelm@19899
   106
val is_body = #is_body o rep_data;
wenzelm@20162
   107
fun set_body b = map_data (fn (_, names, fixes, binds, type_occs, constraints) =>
wenzelm@20162
   108
  (b, names, fixes, binds, type_occs, constraints));
wenzelm@19899
   109
fun restore_body ctxt = set_body (is_body ctxt);
wenzelm@19899
   110
wenzelm@20102
   111
val names_of = #names o rep_data;
wenzelm@20102
   112
val fixes_of = #fixes o rep_data;
wenzelm@19899
   113
val binds_of = #binds o rep_data;
wenzelm@20162
   114
val type_occs_of = #type_occs o rep_data;
wenzelm@20162
   115
val constraints_of = #constraints o rep_data;
wenzelm@19899
   116
wenzelm@20162
   117
val is_declared = Name.is_declared o names_of;
wenzelm@19899
   118
fun is_fixed ctxt x = exists (fn (_, y) => x = y) (fixes_of ctxt);
wenzelm@20149
   119
fun newly_fixed inner outer x = is_fixed inner x andalso not (is_fixed outer x);
wenzelm@19899
   120
wenzelm@19899
   121
wenzelm@19899
   122
wenzelm@19899
   123
(** declarations **)
wenzelm@19899
   124
wenzelm@19899
   125
(* default sorts and types *)
wenzelm@19899
   126
wenzelm@20162
   127
fun default_type ctxt x = Vartab.lookup (#1 (constraints_of ctxt)) (x, ~1);
wenzelm@19899
   128
wenzelm@19899
   129
fun def_type ctxt pattern xi =
wenzelm@20162
   130
  let val {binds, constraints = (types, _), ...} = rep_data ctxt in
wenzelm@19899
   131
    (case Vartab.lookup types xi of
wenzelm@19899
   132
      NONE =>
wenzelm@19899
   133
        if pattern then NONE
wenzelm@19899
   134
        else Vartab.lookup binds xi |> Option.map (TypeInfer.polymorphicT o #1)
wenzelm@19899
   135
    | some => some)
wenzelm@19899
   136
  end;
wenzelm@19899
   137
wenzelm@20162
   138
val def_sort = Vartab.lookup o #2 o constraints_of;
wenzelm@20162
   139
wenzelm@20162
   140
wenzelm@20162
   141
(* names *)
wenzelm@20162
   142
wenzelm@20162
   143
val declare_type_names = map_names o
wenzelm@20162
   144
  fold_types (fold_atyps (fn TFree (a, _) => Name.declare a | _ => I));
wenzelm@20162
   145
wenzelm@20162
   146
fun declare_names t =
wenzelm@20162
   147
  declare_type_names t #>
wenzelm@20162
   148
  map_names (fold_aterms (fn Free (x, _) => Name.declare x | _ => I) t);
wenzelm@20162
   149
wenzelm@20162
   150
wenzelm@20162
   151
(* type occurrences *)
wenzelm@20162
   152
wenzelm@20162
   153
val declare_type_occs = map_type_occs o fold_term_types
wenzelm@20162
   154
  (fn Free (x, _) => fold_atyps (fn TFree (a, _) => Symtab.insert_list (op =) (a, x) | _ => I)
wenzelm@20162
   155
    | _ => fold_atyps (fn TFree (a, _) => Symtab.default (a, []) | _ => I));
wenzelm@19899
   156
wenzelm@19899
   157
wenzelm@20162
   158
(* constraints *)
wenzelm@19899
   159
wenzelm@20162
   160
fun redeclare_skolems ctxt = ctxt |> map_constraints (apfst (fn types =>
wenzelm@20162
   161
  let
wenzelm@20162
   162
    fun decl (x, x') =
wenzelm@20162
   163
      (case default_type ctxt x' of
wenzelm@20162
   164
        SOME T => Vartab.update ((x, ~1), T)
wenzelm@20162
   165
      | NONE => I);
wenzelm@20162
   166
  in fold_rev decl (fixes_of ctxt) types end));
wenzelm@20084
   167
wenzelm@20162
   168
fun declare_constraints t = map_constraints (fn (types, sorts) =>
wenzelm@20162
   169
  let
wenzelm@20162
   170
    val types' = fold_aterms
wenzelm@20162
   171
      (fn Free (x, T) => Vartab.update ((x, ~1), T)
wenzelm@20162
   172
        | Var v => Vartab.update v
wenzelm@20162
   173
        | _ => I) t types;
wenzelm@20162
   174
    val sorts' = fold_types (fold_atyps
wenzelm@20162
   175
      (fn TFree (x, S) => Vartab.update ((x, ~1), S)
wenzelm@20162
   176
        | TVar v => Vartab.update v
wenzelm@20162
   177
        | _ => I)) t sorts;
wenzelm@20162
   178
  in (types', sorts') end)
wenzelm@20162
   179
  #> declare_type_names t
wenzelm@20162
   180
  #> redeclare_skolems;
wenzelm@19899
   181
wenzelm@20162
   182
wenzelm@20162
   183
(* common declarations *)
wenzelm@20162
   184
wenzelm@20162
   185
fun declare_internal t =
wenzelm@20162
   186
  declare_names t #>
wenzelm@20162
   187
  declare_type_occs t;
wenzelm@19911
   188
wenzelm@20162
   189
fun declare_term t =
wenzelm@20162
   190
  declare_internal t #>
wenzelm@20162
   191
  declare_constraints t;
wenzelm@19899
   192
wenzelm@20162
   193
fun declare_thm th = fold declare_internal (Thm.full_prop_of th :: Thm.hyps_of th);
wenzelm@20162
   194
fun thm_context th = declare_thm th (Context.init_proof (Thm.theory_of_thm th));
wenzelm@19899
   195
wenzelm@19899
   196
wenzelm@19899
   197
(* renaming term/type frees *)
wenzelm@19899
   198
wenzelm@20162
   199
fun variant_frees ctxt ts frees =
wenzelm@19899
   200
  let
wenzelm@20162
   201
    val names = names_of (fold declare_names ts ctxt);
wenzelm@20084
   202
    val xs = fst (Name.variants (map #1 frees) names);
wenzelm@20084
   203
  in xs ~~ map snd frees end;
wenzelm@19899
   204
wenzelm@19899
   205
wenzelm@19899
   206
wenzelm@19911
   207
(** fixes **)
wenzelm@19911
   208
wenzelm@20084
   209
local
wenzelm@20084
   210
wenzelm@19911
   211
fun no_dups [] = ()
wenzelm@19911
   212
  | no_dups dups = error ("Duplicate fixed variable(s): " ^ commas_quote dups);
wenzelm@19911
   213
wenzelm@20102
   214
fun new_fixes names' xs xs' =
wenzelm@20102
   215
  map_names (K names') #>
wenzelm@20102
   216
  map_fixes (fn fixes => (rev (xs ~~ xs') @ fixes)) #>
wenzelm@20162
   217
  fold (declare_constraints o Syntax.free) xs' #>
wenzelm@20084
   218
  pair xs';
wenzelm@20084
   219
wenzelm@20084
   220
in
wenzelm@20084
   221
wenzelm@19911
   222
fun add_fixes xs ctxt =
wenzelm@19911
   223
  let
wenzelm@19911
   224
    val _ =
wenzelm@20084
   225
      (case filter (can Name.dest_skolem) xs of [] => ()
wenzelm@19911
   226
      | bads => error ("Illegal internal Skolem constant(s): " ^ commas_quote bads));
wenzelm@20084
   227
    val _ = no_dups (duplicates (op =) xs);
wenzelm@20084
   228
    val (ys, zs) = split_list (fixes_of ctxt);
wenzelm@20102
   229
    val names = names_of ctxt;
wenzelm@20084
   230
    val (xs', names') =
wenzelm@20149
   231
      if is_body ctxt then Name.variants xs names |>> map Name.skolem
wenzelm@20084
   232
      else (no_dups (xs inter_string ys); no_dups (xs inter_string zs);
wenzelm@20084
   233
        (xs, fold Name.declare xs names));
wenzelm@20102
   234
  in ctxt |> new_fixes names' xs xs' end;
wenzelm@19911
   235
wenzelm@20084
   236
fun invent_fixes raw_xs ctxt =
wenzelm@20084
   237
  let
wenzelm@20102
   238
    val names = names_of ctxt;
wenzelm@20149
   239
    val xs = map Name.clean raw_xs;
wenzelm@20149
   240
    val (xs', names') = Name.variants xs names |>> map Name.skolem;
wenzelm@20102
   241
  in ctxt |> new_fixes names' xs xs' end;
wenzelm@20084
   242
wenzelm@20084
   243
end;
wenzelm@19911
   244
wenzelm@19911
   245
fun invent_types Ss ctxt =
wenzelm@19911
   246
  let
wenzelm@20102
   247
    val tfrees = Name.invents (names_of ctxt) "'a" (length Ss) ~~ Ss;
wenzelm@20162
   248
    val ctxt' = fold (declare_constraints o Logic.mk_type o TFree) tfrees ctxt;
wenzelm@19911
   249
  in (tfrees, ctxt') end;
wenzelm@19911
   250
wenzelm@19911
   251
wenzelm@19911
   252
wenzelm@19911
   253
(** export -- generalize type/term variables **)
wenzelm@19911
   254
wenzelm@19911
   255
fun export_inst inner outer =
wenzelm@19911
   256
  let
wenzelm@20162
   257
    val declared_outer = is_declared outer;
wenzelm@19911
   258
    val fixes_inner = fixes_of inner;
wenzelm@19911
   259
    val fixes_outer = fixes_of outer;
wenzelm@19911
   260
wenzelm@19911
   261
    val gen_fixes = map #2 (Library.take (length fixes_inner - length fixes_outer, fixes_inner));
wenzelm@20162
   262
    val still_fixed = not o member (op =) gen_fixes;
wenzelm@19911
   263
    val gen_fixesT =
wenzelm@19911
   264
      Symtab.fold (fn (a, xs) =>
wenzelm@20162
   265
        if declared_outer a orelse exists still_fixed xs
wenzelm@19911
   266
        then I else cons a) (type_occs_of inner) [];
wenzelm@19911
   267
  in (gen_fixesT, gen_fixes) end;
wenzelm@19911
   268
wenzelm@19911
   269
fun exportT_inst inner outer = #1 (export_inst inner outer);
wenzelm@19911
   270
wenzelm@19911
   271
fun exportT_terms inner outer ts =
wenzelm@20162
   272
  map (Term.generalize (exportT_inst (fold declare_type_occs ts inner) outer, [])
wenzelm@19911
   273
    (fold (Term.fold_types Term.maxidx_typ) ts ~1 + 1)) ts;
wenzelm@19911
   274
wenzelm@19911
   275
fun export_terms inner outer ts =
wenzelm@20162
   276
  map (Term.generalize (export_inst (fold declare_type_occs ts inner) outer)
wenzelm@19911
   277
    (fold Term.maxidx_term ts ~1 + 1)) ts;
wenzelm@19911
   278
wenzelm@19911
   279
fun gen_export inst inner outer ths =
wenzelm@19911
   280
  let
wenzelm@19926
   281
    val ths' = map Thm.adjust_maxidx_thm ths;
wenzelm@20162
   282
    val inner' = fold (declare_type_occs o Thm.full_prop_of) ths' inner;
wenzelm@20003
   283
  in map (Thm.generalize (inst inner' outer) (fold Thm.maxidx_thm ths' ~1 + 1)) ths' end;
wenzelm@19911
   284
wenzelm@19911
   285
val exportT = gen_export (rpair [] oo exportT_inst);
wenzelm@19911
   286
val export = gen_export export_inst;
wenzelm@19911
   287
wenzelm@19911
   288
wenzelm@19911
   289
wenzelm@19911
   290
(** import -- fix schematic type/term variables **)
wenzelm@19911
   291
wenzelm@19911
   292
fun importT_inst ts ctxt =
wenzelm@19911
   293
  let
wenzelm@19911
   294
    val tvars = rev (fold Term.add_tvars ts []);
wenzelm@19911
   295
    val (tfrees, ctxt') = invent_types (map #2 tvars) ctxt;
wenzelm@19911
   296
  in (tvars ~~ map TFree tfrees, ctxt') end;
wenzelm@19911
   297
wenzelm@19911
   298
fun import_inst is_open ts ctxt =
wenzelm@19911
   299
  let
wenzelm@20198
   300
    val ren = if is_open then I else Name.internal;
wenzelm@19911
   301
    val (instT, ctxt') = importT_inst ts ctxt;
wenzelm@19911
   302
    val vars = map (apsnd (Term.instantiateT instT)) (rev (fold Term.add_vars ts []));
wenzelm@19911
   303
    val (xs, ctxt'') = invent_fixes (map (ren o #1 o #1) vars) ctxt';
wenzelm@19911
   304
    val inst = vars ~~ map Free (xs ~~ map #2 vars);
wenzelm@19911
   305
  in ((instT, inst), ctxt'') end;
wenzelm@19911
   306
wenzelm@19911
   307
fun importT_terms ts ctxt =
wenzelm@19911
   308
  let val (instT, ctxt') = importT_inst ts ctxt
wenzelm@19911
   309
  in (map (Term.instantiate (instT, [])) ts, ctxt') end;
wenzelm@19911
   310
wenzelm@19911
   311
fun import_terms is_open ts ctxt =
wenzelm@19911
   312
  let val (inst, ctxt') = import_inst is_open ts ctxt
wenzelm@19911
   313
  in (map (Term.instantiate inst) ts, ctxt') end;
wenzelm@19911
   314
wenzelm@19911
   315
fun importT ths ctxt =
wenzelm@19911
   316
  let
wenzelm@19911
   317
    val thy = Context.theory_of_proof ctxt;
wenzelm@19911
   318
    val certT = Thm.ctyp_of thy;
wenzelm@19911
   319
    val (instT, ctxt') = importT_inst (map Thm.full_prop_of ths) ctxt;
wenzelm@19911
   320
    val instT' = map (fn (v, T) => (certT (TVar v), certT T)) instT;
wenzelm@19911
   321
    val ths' = map (Thm.instantiate (instT', [])) ths;
wenzelm@19911
   322
  in (ths', ctxt') end;
wenzelm@19911
   323
wenzelm@19911
   324
fun import is_open ths ctxt =
wenzelm@19911
   325
  let
wenzelm@19911
   326
    val thy = Context.theory_of_proof ctxt;
wenzelm@19911
   327
    val cert = Thm.cterm_of thy;
wenzelm@19911
   328
    val certT = Thm.ctyp_of thy;
wenzelm@19911
   329
    val ((instT, inst), ctxt') = import_inst is_open (map Thm.full_prop_of ths) ctxt;
wenzelm@19911
   330
    val instT' = map (fn (v, T) => (certT (TVar v), certT T)) instT;
wenzelm@19911
   331
    val inst' = map (fn (v, t) => (cert (Var v), cert t)) inst;
wenzelm@19911
   332
    val ths' = map (Thm.instantiate (instT', inst')) ths;
wenzelm@19911
   333
  in (ths', ctxt') end;
wenzelm@19911
   334
wenzelm@19911
   335
wenzelm@19926
   336
(* import/export *)
wenzelm@19926
   337
wenzelm@19926
   338
fun gen_trade imp exp ctxt f ths =
wenzelm@19926
   339
  let val (ths', ctxt') = imp ths ctxt
wenzelm@19926
   340
  in exp ctxt' ctxt (f ths') end;
wenzelm@19926
   341
wenzelm@19926
   342
val tradeT = gen_trade importT exportT;
wenzelm@19926
   343
val trade = gen_trade (import true) export;
wenzelm@19926
   344
wenzelm@19926
   345
wenzelm@20162
   346
(* focus on outermost parameters *)
wenzelm@20149
   347
wenzelm@20149
   348
fun forall_elim_prop t prop =
wenzelm@20149
   349
  Thm.beta_conversion false (Thm.capply (#2 (Thm.dest_comb prop)) t)
wenzelm@20149
   350
  |> Thm.cprop_of |> Thm.dest_comb |> #2;
wenzelm@20149
   351
wenzelm@20149
   352
fun focus goal ctxt =
wenzelm@20149
   353
  let
wenzelm@20149
   354
    val cert = Thm.cterm_of (Thm.theory_of_cterm goal);
wenzelm@20149
   355
    val t = Thm.term_of goal;
wenzelm@20162
   356
    val ps = Term.variant_frees t (Term.strip_all_vars t);   (*as they are printed :-*)
wenzelm@20149
   357
    val (xs, Ts) = split_list ps;
wenzelm@20149
   358
    val (xs', ctxt') = invent_fixes xs ctxt;
wenzelm@20149
   359
    val ps' = xs' ~~ Ts;
wenzelm@20149
   360
    val goal' = fold (forall_elim_prop o cert o Free) ps' goal;
wenzelm@20149
   361
  in ((ps', goal'), ctxt') end;
wenzelm@20149
   362
wenzelm@19911
   363
wenzelm@19911
   364
(** implicit polymorphism **)
wenzelm@19899
   365
wenzelm@19899
   366
(* warn_extra_tfrees *)
wenzelm@19899
   367
wenzelm@19899
   368
fun warn_extra_tfrees ctxt1 ctxt2 =
wenzelm@19899
   369
  let
wenzelm@19911
   370
    fun occs_typ a = Term.exists_subtype (fn TFree (b, _) => a = b | _ => false);
wenzelm@20162
   371
    fun occs_free a x =
wenzelm@20162
   372
      (case def_type ctxt1 false (x, ~1) of
wenzelm@20162
   373
        SOME T => if occs_typ a T then I else cons (a, x)
wenzelm@20162
   374
      | NONE => cons (a, x));
wenzelm@19899
   375
wenzelm@20162
   376
    val occs1 = type_occs_of ctxt1;
wenzelm@20162
   377
    val occs2 = type_occs_of ctxt2;
wenzelm@19911
   378
    val extras = Symtab.fold (fn (a, xs) =>
wenzelm@19911
   379
      if Symtab.defined occs1 a then I else fold (occs_free a) xs) occs2 [];
wenzelm@19899
   380
    val tfrees = map #1 extras |> sort_distinct string_ord;
wenzelm@19899
   381
    val frees = map #2 extras |> sort_distinct string_ord;
wenzelm@19899
   382
  in
wenzelm@19899
   383
    if null extras then ()
wenzelm@19899
   384
    else warning ("Introduced fixed type variable(s): " ^ commas tfrees ^ " in " ^
wenzelm@19899
   385
      space_implode " or " (map quote frees))
wenzelm@19899
   386
  end;
wenzelm@19899
   387
wenzelm@19899
   388
wenzelm@20149
   389
(* polymorphic terms *)
wenzelm@19899
   390
wenzelm@19899
   391
fun polymorphic ctxt ts =
wenzelm@20003
   392
  let
wenzelm@20003
   393
    val ctxt' = fold declare_term ts ctxt;
wenzelm@20162
   394
    val occs = type_occs_of ctxt;
wenzelm@20162
   395
    val occs' = type_occs_of ctxt';
wenzelm@20162
   396
    val types = Symtab.fold (fn (a, _) => if Symtab.defined occs a then I else cons a) occs' [];
wenzelm@20003
   397
    val idx = fold (Term.fold_types Term.maxidx_typ) ts ~1 + 1;
wenzelm@20003
   398
  in map (Term.generalize (types, []) idx) ts end;
wenzelm@20003
   399
wenzelm@19899
   400
fun hidden_polymorphism t T =
wenzelm@19899
   401
  let
wenzelm@19899
   402
    val tvarsT = Term.add_tvarsT T [];
wenzelm@19899
   403
    val extra_tvars = Term.fold_types (Term.fold_atyps
wenzelm@19899
   404
      (fn TVar v => if member (op =) tvarsT v then I else insert (op =) v | _ => I)) t [];
wenzelm@19899
   405
  in extra_tvars end;
wenzelm@19899
   406
wenzelm@20162
   407
wenzelm@20162
   408
wenzelm@20162
   409
(** term bindings **)
wenzelm@20162
   410
wenzelm@19899
   411
fun add_bind (xi, NONE) = map_binds (Vartab.delete_safe xi)
wenzelm@19899
   412
  | add_bind ((x, i), SOME t) =
wenzelm@19899
   413
      let
wenzelm@19899
   414
        val T = Term.fastype_of t;
wenzelm@19899
   415
        val t' =
wenzelm@19899
   416
          if null (hidden_polymorphism t T) then t
wenzelm@19899
   417
          else Var ((x ^ "_has_extra_type_vars_on_rhs", i), T);
wenzelm@19899
   418
      in declare_term t' #> map_binds (Vartab.update ((x, i), (T, t'))) end;
wenzelm@19899
   419
wenzelm@19899
   420
val add_binds = fold add_bind;
wenzelm@19899
   421
wenzelm@19899
   422
fun expand_binds ctxt =
wenzelm@19899
   423
  let
wenzelm@19899
   424
    val binds = binds_of ctxt;
wenzelm@19899
   425
    fun expand (t as Var (xi, T)) =
wenzelm@19899
   426
          (case Vartab.lookup binds xi of
wenzelm@19899
   427
            SOME u => Envir.expand_atom T u
wenzelm@19899
   428
          | NONE => t)
wenzelm@19899
   429
      | expand t = t;
wenzelm@19899
   430
  in Envir.beta_norm o Term.map_aterms expand end;
wenzelm@19899
   431
wenzelm@19899
   432
end;