src/HOL/Codatatype/Tools/bnf_sugar.ML
author blanchet
Thu Aug 30 16:50:03 2012 +0200 (2012-08-30)
changeset 49032 c2a7bedd57d8
parent 49031 632ee0da3c5b
child 49033 23ef2d429931
permissions -rw-r--r--
generate "case_cong" property
blanchet@49017
     1
(*  Title:      HOL/Codatatype/Tools/bnf_sugar.ML
blanchet@49017
     2
    Author:     Jasmin Blanchette, TU Muenchen
blanchet@49017
     3
    Copyright   2012
blanchet@49017
     4
blanchet@49017
     5
Sugar on top of a BNF.
blanchet@49017
     6
*)
blanchet@49017
     7
blanchet@49017
     8
signature BNF_SUGAR =
blanchet@49017
     9
sig
blanchet@49017
    10
end;
blanchet@49017
    11
blanchet@49017
    12
structure BNF_Sugar : BNF_SUGAR =
blanchet@49017
    13
struct
blanchet@49017
    14
blanchet@49017
    15
open BNF_Util
blanchet@49019
    16
open BNF_FP_Util
blanchet@49020
    17
open BNF_Sugar_Tactics
blanchet@49017
    18
blanchet@49025
    19
val case_congN = "case_cong"
blanchet@49025
    20
val case_discsN = "case_discs"
blanchet@49025
    21
val casesN = "cases"
blanchet@49025
    22
val ctr_selsN = "ctr_sels"
blanchet@49025
    23
val disc_disjointN = "disc_disjoint"
blanchet@49027
    24
val disc_exhaustN = "disc_exhaust"
blanchet@49027
    25
val discsN = "discs"
blanchet@49025
    26
val distinctN = "distinct"
blanchet@49025
    27
val selsN = "sels"
blanchet@49025
    28
val splitN = "split"
blanchet@49025
    29
val split_asmN = "split_asm"
blanchet@49025
    30
val weak_case_cong_thmsN = "weak_case_cong"
blanchet@49019
    31
blanchet@49028
    32
fun mk_half_pairs [] = []
blanchet@49028
    33
  | mk_half_pairs (x :: xs) = fold_rev (cons o pair x) xs (mk_half_pairs xs);
blanchet@49027
    34
blanchet@49028
    35
fun index_of_half_row _ 0 = 0
blanchet@49028
    36
  | index_of_half_row n j = index_of_half_row n (j - 1) + n - j;
blanchet@49028
    37
blanchet@49028
    38
fun index_of_half_cell n j k = index_of_half_row n j + k - (j + 1);
blanchet@49027
    39
blanchet@49032
    40
val mk_Trueprop_eq = HOLogic.mk_Trueprop o HOLogic.mk_eq;
blanchet@49032
    41
blanchet@49032
    42
fun eta_expand_caseof_arg f xs = fold_rev Term.lambda xs (Term.list_comb (f, xs));
blanchet@49032
    43
blanchet@49025
    44
fun prepare_sugar prep_term (((raw_ctrs, raw_caseof), disc_names), sel_namess) no_defs_lthy =
blanchet@49017
    45
  let
blanchet@49019
    46
    (* TODO: sanity checks on arguments *)
blanchet@49017
    47
blanchet@49025
    48
    (* TODO: normalize types of constructors w.r.t. each other *)
blanchet@49025
    49
blanchet@49025
    50
    val ctrs0 = map (prep_term no_defs_lthy) raw_ctrs;
blanchet@49025
    51
    val caseof0 = prep_term no_defs_lthy raw_caseof;
blanchet@49017
    52
blanchet@49025
    53
    val n = length ctrs0;
blanchet@49025
    54
    val ks = 1 upto n;
blanchet@49022
    55
blanchet@49025
    56
    val (T_name, As0) = dest_Type (body_type (fastype_of (hd ctrs0)));
blanchet@49020
    57
    val b = Binding.qualified_name T_name;
blanchet@49020
    58
blanchet@49025
    59
    val (As, B) =
blanchet@49025
    60
      no_defs_lthy
blanchet@49025
    61
      |> mk_TFrees (length As0)
blanchet@49025
    62
      ||> the_single o fst o mk_TFrees 1;
blanchet@49025
    63
blanchet@49025
    64
    fun mk_undef T Ts = Const (@{const_name undefined}, Ts ---> T);
blanchet@49025
    65
blanchet@49025
    66
    fun mk_ctr Ts ctr =
blanchet@49028
    67
      let val Ts0 = snd (dest_Type (body_type (fastype_of ctr))) in
blanchet@49025
    68
        Term.subst_atomic_types (Ts0 ~~ Ts) ctr
blanchet@49025
    69
      end;
blanchet@49020
    70
blanchet@49028
    71
    fun mk_caseof Ts T =
blanchet@49028
    72
      let val (binders, body) = strip_type (fastype_of caseof0) in
blanchet@49028
    73
        Term.subst_atomic_types ((body, T) :: (snd (dest_Type (List.last binders)) ~~ Ts)) caseof0
blanchet@49022
    74
      end;
blanchet@49022
    75
blanchet@49025
    76
    val T = Type (T_name, As);
blanchet@49025
    77
    val ctrs = map (mk_ctr As) ctrs0;
blanchet@49025
    78
    val ctr_Tss = map (binder_types o fastype_of) ctrs;
blanchet@49025
    79
blanchet@49028
    80
    val ms = map length ctr_Tss;
blanchet@49028
    81
blanchet@49028
    82
    val caseofB = mk_caseof As B;
blanchet@49025
    83
    val caseofB_Ts = map (fn Ts => Ts ---> B) ctr_Tss;
blanchet@49025
    84
blanchet@49032
    85
    val (((((((xss, yss), fs), gs), (v, v')), w), p), names_lthy) = no_defs_lthy |>
blanchet@49025
    86
      mk_Freess "x" ctr_Tss
blanchet@49025
    87
      ||>> mk_Freess "y" ctr_Tss
blanchet@49025
    88
      ||>> mk_Frees "f" caseofB_Ts
blanchet@49032
    89
      ||>> mk_Frees "g" caseofB_Ts
blanchet@49020
    90
      ||>> yield_singleton (apfst (op ~~) oo mk_Frees' "v") T
blanchet@49032
    91
      ||>> yield_singleton (mk_Frees "w") T
blanchet@49020
    92
      ||>> yield_singleton (mk_Frees "P") HOLogic.boolT;
blanchet@49020
    93
blanchet@49025
    94
    val xctrs = map2 (curry Term.list_comb) ctrs xss;
blanchet@49025
    95
    val yctrs = map2 (curry Term.list_comb) ctrs yss;
blanchet@49032
    96
blanchet@49032
    97
    val eta_fs = map2 eta_expand_caseof_arg fs xss;
blanchet@49032
    98
    val eta_gs = map2 eta_expand_caseof_arg gs xss;
blanchet@49020
    99
blanchet@49025
   100
    val exist_xs_v_eq_ctrs =
blanchet@49025
   101
      map2 (fn xctr => fn xs => list_exists_free xs (HOLogic.mk_eq (v, xctr))) xctrs xss;
blanchet@49022
   102
blanchet@49032
   103
    fun mk_sel_caseof_args k xs x T =
blanchet@49025
   104
      map2 (fn Ts => fn i => if i = k then fold_rev Term.lambda xs x else mk_undef T Ts) ctr_Tss ks;
blanchet@49025
   105
blanchet@49025
   106
    fun disc_spec b exist_xs_v_eq_ctr =
blanchet@49032
   107
      mk_Trueprop_eq (Free (Binding.name_of b, T --> HOLogic.boolT) $ v, exist_xs_v_eq_ctr);
blanchet@49025
   108
blanchet@49028
   109
    fun sel_spec b x xs k =
blanchet@49025
   110
      let val T' = fastype_of x in
blanchet@49032
   111
        mk_Trueprop_eq (Free (Binding.name_of b, T --> T') $ v,
blanchet@49032
   112
          Term.list_comb (mk_caseof As T', mk_sel_caseof_args k xs x T') $ v)
blanchet@49022
   113
      end;
blanchet@49022
   114
blanchet@49028
   115
    val (((raw_discs, (_, raw_disc_defs)), (raw_selss, (_, raw_sel_defss))), (lthy', lthy)) =
blanchet@49022
   116
      no_defs_lthy
blanchet@49025
   117
      |> apfst (apsnd split_list o split_list) o fold_map2 (fn b => fn exist_xs_v_eq_ctr =>
blanchet@49022
   118
        Specification.definition (SOME (b, NONE, NoSyn),
blanchet@49025
   119
          ((Thm.def_binding b, []), disc_spec b exist_xs_v_eq_ctr))) disc_names exist_xs_v_eq_ctrs
blanchet@49028
   120
      ||>> apfst (apsnd split_list o split_list) o fold_map3 (fn bs => fn xs => fn k =>
blanchet@49025
   121
        apfst (apsnd split_list o split_list) o fold_map2 (fn b => fn x =>
blanchet@49022
   122
          Specification.definition (SOME (b, NONE, NoSyn),
blanchet@49028
   123
            ((Thm.def_binding b, []), sel_spec b x xs k))) bs xs) sel_namess xss ks
blanchet@49022
   124
      ||> `Local_Theory.restore;
blanchet@49022
   125
blanchet@49025
   126
    (*transforms defined frees into consts (and more)*)
blanchet@49025
   127
    val phi = Proof_Context.export_morphism lthy lthy';
blanchet@49025
   128
blanchet@49028
   129
    val disc_defs = map (Morphism.thm phi) raw_disc_defs;
blanchet@49028
   130
    val sel_defss = map (map (Morphism.thm phi)) raw_sel_defss;
blanchet@49028
   131
blanchet@49028
   132
    val discs0 = map (Morphism.term phi) raw_discs;
blanchet@49028
   133
    val selss0 = map (map (Morphism.term phi)) raw_selss;
blanchet@49025
   134
blanchet@49028
   135
    fun mk_disc_or_sel Ts t =
blanchet@49028
   136
      Term.subst_atomic_types (snd (dest_Type (domain_type (fastype_of t))) ~~ Ts) t;
blanchet@49028
   137
blanchet@49028
   138
    val discs = map (mk_disc_or_sel As) discs0;
blanchet@49028
   139
    val selss = map (map (mk_disc_or_sel As)) selss0;
blanchet@49025
   140
blanchet@49032
   141
    fun mk_imp_p Qs = Logic.list_implies (Qs, HOLogic.mk_Trueprop p);
blanchet@49029
   142
blanchet@49020
   143
    val goal_exhaust =
blanchet@49032
   144
      let fun mk_prem xctr xs = fold_rev Logic.all xs (mk_imp_p [mk_Trueprop_eq (v, xctr)]) in
blanchet@49025
   145
        mk_imp_p (map2 mk_prem xctrs xss)
blanchet@49020
   146
      end;
blanchet@49019
   147
blanchet@49019
   148
    val goal_injects =
blanchet@49017
   149
      let
blanchet@49020
   150
        fun mk_goal _ _ [] [] = NONE
blanchet@49025
   151
          | mk_goal xctr yctr xs ys =
blanchet@49032
   152
            SOME (mk_Trueprop_eq (HOLogic.mk_eq (xctr, yctr),
blanchet@49032
   153
              Library.foldr1 HOLogic.mk_conj (map2 (curry HOLogic.mk_eq) xs ys)));
blanchet@49017
   154
      in
blanchet@49025
   155
        map_filter I (map4 mk_goal xctrs yctrs xss yss)
blanchet@49017
   156
      end;
blanchet@49017
   157
blanchet@49019
   158
    val goal_half_distincts =
blanchet@49028
   159
      map (HOLogic.mk_Trueprop o HOLogic.mk_not o HOLogic.mk_eq) (mk_half_pairs xctrs);
blanchet@49019
   160
blanchet@49025
   161
    val goal_cases =
blanchet@49025
   162
      let
blanchet@49025
   163
        val lhs0 = Term.list_comb (caseofB, eta_fs);
blanchet@49032
   164
        fun mk_goal xctr xs f = mk_Trueprop_eq (lhs0 $ xctr, Term.list_comb (f, xs));
blanchet@49025
   165
      in
blanchet@49028
   166
        map3 mk_goal xctrs xss fs
blanchet@49025
   167
      end;
blanchet@49025
   168
blanchet@49025
   169
    val goals = [[goal_exhaust], goal_injects, goal_half_distincts, goal_cases];
blanchet@49019
   170
blanchet@49019
   171
    fun after_qed thmss lthy =
blanchet@49019
   172
      let
blanchet@49025
   173
        val [[exhaust_thm], inject_thms, half_distinct_thms, case_thms] = thmss;
blanchet@49019
   174
blanchet@49032
   175
        val exhaust_thm' =
blanchet@49032
   176
          let val Tinst = map (pairself (certifyT lthy)) (map Logic.varifyT_global As ~~ As) in
blanchet@49032
   177
            Drule.instantiate' [] [SOME (certify lthy v)]
blanchet@49032
   178
              (Thm.instantiate (Tinst, []) (Drule.zero_var_indexes exhaust_thm))
blanchet@49032
   179
          end;
blanchet@49032
   180
blanchet@49019
   181
        val other_half_distinct_thms = map (fn thm => thm RS not_sym) half_distinct_thms;
blanchet@49019
   182
blanchet@49020
   183
        val nchotomy_thm =
blanchet@49020
   184
          let
blanchet@49020
   185
            val goal =
blanchet@49022
   186
              HOLogic.mk_Trueprop (HOLogic.mk_all (fst v', snd v',
blanchet@49029
   187
                Library.foldr1 HOLogic.mk_disj exist_xs_v_eq_ctrs));
blanchet@49020
   188
          in
blanchet@49020
   189
            Skip_Proof.prove lthy [] [] goal (fn _ => mk_nchotomy_tac n exhaust_thm)
blanchet@49020
   190
          end;
blanchet@49020
   191
blanchet@49030
   192
        val sel_thmss =
blanchet@49025
   193
          let
blanchet@49028
   194
            fun mk_thm k xs goal_case case_thm x sel_def =
blanchet@49025
   195
              let
blanchet@49025
   196
                val T = fastype_of x;
blanchet@49025
   197
                val cTs =
blanchet@49025
   198
                  map ((fn T' => certifyT lthy (if T' = B then T else T')) o TFree)
blanchet@49025
   199
                    (rev (Term.add_tfrees goal_case []));
blanchet@49032
   200
                val cxs = map (certify lthy) (mk_sel_caseof_args k xs x T);
blanchet@49025
   201
              in
blanchet@49025
   202
                Local_Defs.fold lthy [sel_def]
blanchet@49025
   203
                  (Drule.instantiate' (map SOME cTs) (map SOME cxs) case_thm)
blanchet@49025
   204
              end;
blanchet@49028
   205
            fun mk_thms k xs goal_case case_thm sel_defs =
blanchet@49028
   206
              map2 (mk_thm k xs goal_case case_thm) xs sel_defs;
blanchet@49025
   207
          in
blanchet@49030
   208
            map5 mk_thms ks xss goal_cases case_thms sel_defss
blanchet@49025
   209
          end;
blanchet@49025
   210
blanchet@49030
   211
        val discD_thms = map (fn def => def RS iffD1) disc_defs;
blanchet@49028
   212
        val discI_thms =
blanchet@49030
   213
          map2 (fn m => fn def => funpow m (fn thm => exI RS thm) (def RS iffD2)) ms disc_defs;
blanchet@49028
   214
        val not_disc_thms =
blanchet@49030
   215
          map2 (fn m => fn def => funpow m (fn thm => allI RS thm)
blanchet@49030
   216
                  (Local_Defs.unfold lthy @{thms not_ex} (def RS @{thm ssubst[of _ _ Not]})))
blanchet@49028
   217
            ms disc_defs;
blanchet@49028
   218
blanchet@49027
   219
        val disc_thms =
blanchet@49027
   220
          let
blanchet@49027
   221
            fun get_distinct_thm k k' =
blanchet@49028
   222
              if k > k' then nth half_distinct_thms (index_of_half_cell n (k' - 1) (k - 1))
blanchet@49028
   223
              else nth other_half_distinct_thms (index_of_half_cell n (k' - 1) (k' - 1))
blanchet@49028
   224
            fun mk_thm ((k, discI), not_disc) k' =
blanchet@49028
   225
              if k = k' then refl RS discI else get_distinct_thm k k' RS not_disc;
blanchet@49027
   226
          in
blanchet@49028
   227
            map_product mk_thm (ks ~~ discI_thms ~~ not_disc_thms) ks
blanchet@49027
   228
          end;
blanchet@49025
   229
blanchet@49028
   230
        val disc_disjoint_thms =
blanchet@49028
   231
          let
blanchet@49028
   232
            fun get_disc_thm k k' = nth disc_thms ((k' - 1) * n + (k - 1));
blanchet@49028
   233
            fun mk_goal ((_, disc), (_, disc')) =
blanchet@49029
   234
              Logic.all v (Logic.mk_implies (HOLogic.mk_Trueprop (disc $ v),
blanchet@49029
   235
                HOLogic.mk_Trueprop (HOLogic.mk_not (disc' $ v))));
blanchet@49028
   236
            fun prove tac goal = Skip_Proof.prove lthy [] [] goal (K tac);
blanchet@49028
   237
blanchet@49030
   238
            val bundles = ks ~~ ms ~~ discD_thms ~~ discs;
blanchet@49028
   239
            val half_pairs = mk_half_pairs bundles;
blanchet@49028
   240
blanchet@49028
   241
            val goal_halves = map mk_goal half_pairs;
blanchet@49028
   242
            val half_thms =
blanchet@49030
   243
              map2 (fn ((((k, m), discD), _), (((k', _), _), _)) =>
blanchet@49030
   244
                prove (mk_half_disc_disjoint_tac m discD (get_disc_thm k k')))
blanchet@49028
   245
              half_pairs goal_halves;
blanchet@49028
   246
blanchet@49028
   247
            val goal_other_halves = map (mk_goal o swap) half_pairs;
blanchet@49028
   248
            val other_half_thms =
blanchet@49028
   249
              map2 (prove o mk_other_half_disc_disjoint_tac) half_thms goal_other_halves;
blanchet@49028
   250
          in
blanchet@49028
   251
            half_thms @ other_half_thms
blanchet@49028
   252
          end;
blanchet@49025
   253
blanchet@49029
   254
        val disc_exhaust_thm =
blanchet@49029
   255
          let
blanchet@49029
   256
            fun mk_prem disc = mk_imp_p [HOLogic.mk_Trueprop (disc $ v)];
blanchet@49029
   257
            val goal = fold Logic.all [p, v] (mk_imp_p (map mk_prem discs));
blanchet@49029
   258
          in
blanchet@49029
   259
            Skip_Proof.prove lthy [] [] goal (fn _ => mk_disc_exhaust_tac n exhaust_thm discI_thms)
blanchet@49029
   260
          end;
blanchet@49025
   261
blanchet@49030
   262
        val ctr_sel_thms =
blanchet@49030
   263
          let
blanchet@49030
   264
            fun mk_goal ctr disc sels =
blanchet@49030
   265
              Logic.all v (Logic.mk_implies (HOLogic.mk_Trueprop (disc $ v),
blanchet@49032
   266
                mk_Trueprop_eq ((null sels ? swap)
blanchet@49032
   267
                  (Term.list_comb (ctr, map (fn sel => sel $ v) sels), v))));
blanchet@49030
   268
            val goals = map3 mk_goal ctrs discs selss;
blanchet@49030
   269
          in
blanchet@49030
   270
            map4 (fn goal => fn m => fn discD => fn sel_thms =>
blanchet@49030
   271
              Skip_Proof.prove lthy [] [] goal (fn {context = ctxt, ...} =>
blanchet@49030
   272
                mk_ctr_sel_tac ctxt m discD sel_thms))
blanchet@49030
   273
              goals ms discD_thms sel_thmss
blanchet@49030
   274
          end;
blanchet@49025
   275
blanchet@49031
   276
        val case_disc_thm =
blanchet@49031
   277
          let
blanchet@49031
   278
            fun mk_core f sels = Term.list_comb (f, map (fn sel => sel $ v) sels);
blanchet@49031
   279
            fun mk_rhs _ [f] [sels] = mk_core f sels
blanchet@49031
   280
              | mk_rhs (disc :: discs) (f :: fs) (sels :: selss) =
blanchet@49031
   281
                Const (@{const_name If}, HOLogic.boolT --> B --> B --> B) $
blanchet@49031
   282
                  (disc $ v) $ mk_core f sels $ mk_rhs discs fs selss;
blanchet@49031
   283
blanchet@49031
   284
            val lhs = Term.list_comb (caseofB, eta_fs) $ v;
blanchet@49031
   285
            val rhs = mk_rhs discs fs selss;
blanchet@49032
   286
            val goal = mk_Trueprop_eq (lhs, rhs);
blanchet@49031
   287
          in
blanchet@49031
   288
            Skip_Proof.prove lthy [] [] goal (fn {context = ctxt, ...} =>
blanchet@49031
   289
              mk_case_disc_tac ctxt exhaust_thm' case_thms disc_thms sel_thmss)
blanchet@49031
   290
            |> singleton (Proof_Context.export names_lthy lthy)
blanchet@49031
   291
          end;
blanchet@49025
   292
blanchet@49032
   293
        val case_cong_thm =
blanchet@49032
   294
          let
blanchet@49032
   295
            fun mk_prem xctr xs f g =
blanchet@49032
   296
              fold_rev Logic.all xs (Logic.mk_implies (mk_Trueprop_eq (v, xctr),
blanchet@49032
   297
                mk_Trueprop_eq (f, g)));
blanchet@49032
   298
            fun mk_caseof_term fs v = Term.list_comb (caseofB, fs) $ v;
blanchet@49032
   299
blanchet@49032
   300
            val goal =
blanchet@49032
   301
              Logic.list_implies (mk_Trueprop_eq (v, w) :: map4 mk_prem xctrs xss fs gs,
blanchet@49032
   302
                 mk_Trueprop_eq (mk_caseof_term eta_fs v, mk_caseof_term eta_gs w));
blanchet@49032
   303
          in
blanchet@49032
   304
            Skip_Proof.prove lthy [] [] goal (fn {context = ctxt, ...} =>
blanchet@49032
   305
              mk_case_cong_tac ctxt exhaust_thm' case_thms)
blanchet@49032
   306
            |> singleton (Proof_Context.export names_lthy lthy)
blanchet@49032
   307
          end;
blanchet@49025
   308
blanchet@49025
   309
        val weak_case_cong_thms = TrueI;
blanchet@49025
   310
blanchet@49025
   311
        val split_thms = [];
blanchet@49025
   312
blanchet@49025
   313
        val split_asm_thms = [];
blanchet@49025
   314
blanchet@49025
   315
        (* case syntax *)
blanchet@49025
   316
blanchet@49019
   317
        fun note thmN thms =
blanchet@49019
   318
          snd o Local_Theory.note
blanchet@49019
   319
            ((Binding.qualify true (Binding.name_of b) (Binding.name thmN), []), thms);
blanchet@49019
   320
      in
blanchet@49019
   321
        lthy
blanchet@49025
   322
        |> note case_congN [case_cong_thm]
blanchet@49031
   323
        |> note case_discsN [case_disc_thm]
blanchet@49025
   324
        |> note casesN case_thms
blanchet@49025
   325
        |> note ctr_selsN ctr_sel_thms
blanchet@49027
   326
        |> note discsN disc_thms
blanchet@49025
   327
        |> note disc_disjointN disc_disjoint_thms
blanchet@49029
   328
        |> note disc_exhaustN [disc_exhaust_thm]
blanchet@49020
   329
        |> note distinctN (half_distinct_thms @ other_half_distinct_thms)
blanchet@49020
   330
        |> note exhaustN [exhaust_thm]
blanchet@49019
   331
        |> note injectN inject_thms
blanchet@49020
   332
        |> note nchotomyN [nchotomy_thm]
blanchet@49030
   333
        |> note selsN (flat sel_thmss)
blanchet@49025
   334
        |> note splitN split_thms
blanchet@49025
   335
        |> note split_asmN split_asm_thms
blanchet@49025
   336
        |> note weak_case_cong_thmsN [weak_case_cong_thms]
blanchet@49019
   337
      end;
blanchet@49017
   338
  in
blanchet@49025
   339
    (goals, after_qed, lthy')
blanchet@49017
   340
  end;
blanchet@49017
   341
blanchet@49017
   342
val parse_binding_list = Parse.$$$ "[" |--  Parse.list Parse.binding --| Parse.$$$ "]";
blanchet@49017
   343
blanchet@49019
   344
val bnf_sugar_cmd = (fn (goalss, after_qed, lthy) =>
blanchet@49019
   345
  Proof.theorem NONE after_qed (map (map (rpair [])) goalss) lthy) oo
blanchet@49020
   346
  prepare_sugar Syntax.read_term;
blanchet@49017
   347
blanchet@49017
   348
val _ =
blanchet@49017
   349
  Outer_Syntax.local_theory_to_proof @{command_spec "bnf_sugar"} "adds sugar on top of a BNF"
blanchet@49023
   350
    (((Parse.$$$ "[" |-- Parse.list Parse.term --| Parse.$$$ "]") -- Parse.term --
blanchet@49023
   351
      parse_binding_list -- (Parse.$$$ "[" |-- Parse.list parse_binding_list --| Parse.$$$ "]"))
blanchet@49023
   352
      >> bnf_sugar_cmd);
blanchet@49017
   353
blanchet@49017
   354
end;