src/HOL/Tools/datatype_codegen.ML
author haftmann
Fri Aug 24 14:14:20 2007 +0200 (2007-08-24)
changeset 24423 ae9cd0e92423
parent 24219 e558fe311376
child 24428 fcf429a4e923
permissions -rw-r--r--
overloaded definitions accompanied by explicit constants
     1 (*  Title:      HOL/datatype_codegen.ML
     2     ID:         $Id$
     3     Author:     Stefan Berghofer & Florian Haftmann, TU Muenchen
     4 
     5 Code generator for inductive datatypes.
     6 *)
     7 
     8 signature DATATYPE_CODEGEN =
     9 sig
    10   val get_eq: theory -> string -> thm list
    11   val get_eq_datatype: theory -> string -> thm list
    12   val dest_case_expr: theory -> term
    13     -> ((string * typ) list * ((term * typ) * (term * term) list)) option
    14   val get_case_cert: theory -> string -> thm
    15 
    16   type hook = (string * (bool * ((string * sort) list * (string * typ list) list))) list
    17     -> theory -> theory
    18   val codetype_hook: hook
    19   val eq_hook: hook
    20   val codetypes_dependency: theory -> (string * bool) list list
    21   val add_codetypes_hook_bootstrap: hook -> theory -> theory
    22   val the_codetypes_mut_specs: theory -> (string * bool) list
    23     -> ((string * sort) list * (string * (bool * (string * typ list) list)) list)
    24   val get_codetypes_arities: theory -> (string * bool) list -> sort
    25     -> (string * (arity * term list)) list option
    26   val prove_codetypes_arities: tactic -> (string * bool) list -> sort
    27     -> (arity list -> (string * term list) list -> theory
    28       -> ((bstring * Attrib.src list) * term) list * theory)
    29     -> (arity list -> (string * term list) list -> thm list -> theory -> theory)
    30     -> theory -> theory
    31 
    32   val setup: theory -> theory
    33   val setup_hooks: theory -> theory
    34 end;
    35 
    36 structure DatatypeCodegen : DATATYPE_CODEGEN =
    37 struct
    38 
    39 open Codegen;
    40 
    41 fun mk_tuple [p] = p
    42   | mk_tuple ps = Pretty.block (Pretty.str "(" ::
    43       List.concat (separate [Pretty.str ",", Pretty.brk 1] (map single ps)) @
    44         [Pretty.str ")"]);
    45 
    46 (**** datatype definition ****)
    47 
    48 (* find shortest path to constructor with no recursive arguments *)
    49 
    50 fun find_nonempty (descr: DatatypeAux.descr) is i =
    51   let
    52     val (_, _, constrs) = valOf (AList.lookup (op =) descr i);
    53     fun arg_nonempty (_, DatatypeAux.DtRec i) = if i mem is then NONE
    54           else Option.map (curry op + 1 o snd) (find_nonempty descr (i::is) i)
    55       | arg_nonempty _ = SOME 0;
    56     fun max xs = Library.foldl
    57       (fn (NONE, _) => NONE
    58         | (SOME i, SOME j) => SOME (Int.max (i, j))
    59         | (_, NONE) => NONE) (SOME 0, xs);
    60     val xs = sort (int_ord o pairself snd)
    61       (List.mapPartial (fn (s, dts) => Option.map (pair s)
    62         (max (map (arg_nonempty o DatatypeAux.strip_dtyp) dts))) constrs)
    63   in case xs of [] => NONE | x :: _ => SOME x end;
    64 
    65 fun add_dt_defs thy defs dep module gr (descr: DatatypeAux.descr) =
    66   let
    67     val descr' = List.filter (can (map DatatypeAux.dest_DtTFree o #2 o snd)) descr;
    68     val rtnames = map (#1 o snd) (List.filter (fn (_, (_, _, cs)) =>
    69       exists (exists DatatypeAux.is_rec_type o snd) cs) descr');
    70 
    71     val (_, (tname, _, _)) :: _ = descr';
    72     val node_id = tname ^ " (type)";
    73     val module' = if_library (thyname_of_type tname thy) module;
    74 
    75     fun mk_dtdef gr prfx [] = (gr, [])
    76       | mk_dtdef gr prfx ((_, (tname, dts, cs))::xs) =
    77           let
    78             val tvs = map DatatypeAux.dest_DtTFree dts;
    79             val sorts = map (rpair []) tvs;
    80             val cs' = map (apsnd (map (DatatypeAux.typ_of_dtyp descr sorts))) cs;
    81             val (gr', (_, type_id)) = mk_type_id module' tname gr;
    82             val (gr'', ps) =
    83               foldl_map (fn (gr, (cname, cargs)) =>
    84                 foldl_map (invoke_tycodegen thy defs node_id module' false)
    85                   (gr, cargs) |>>>
    86                 mk_const_id module' cname) (gr', cs');
    87             val (gr''', rest) = mk_dtdef gr'' "and " xs
    88           in
    89             (gr''',
    90              Pretty.block (Pretty.str prfx ::
    91                (if null tvs then [] else
    92                   [mk_tuple (map Pretty.str tvs), Pretty.str " "]) @
    93                [Pretty.str (type_id ^ " ="), Pretty.brk 1] @
    94                List.concat (separate [Pretty.brk 1, Pretty.str "| "]
    95                  (map (fn (ps', (_, cname)) => [Pretty.block
    96                    (Pretty.str cname ::
    97                     (if null ps' then [] else
    98                      List.concat ([Pretty.str " of", Pretty.brk 1] ::
    99                        separate [Pretty.str " *", Pretty.brk 1]
   100                          (map single ps'))))]) ps))) :: rest)
   101           end;
   102 
   103     fun mk_term_of_def gr prfx [] = []
   104       | mk_term_of_def gr prfx ((_, (tname, dts, cs)) :: xs) =
   105           let
   106             val tvs = map DatatypeAux.dest_DtTFree dts;
   107             val sorts = map (rpair []) tvs;
   108             val cs' = map (apsnd (map (DatatypeAux.typ_of_dtyp descr sorts))) cs;
   109             val dts' = map (DatatypeAux.typ_of_dtyp descr sorts) dts;
   110             val T = Type (tname, dts');
   111             val rest = mk_term_of_def gr "and " xs;
   112             val (_, eqs) = foldl_map (fn (prfx, (cname, Ts)) =>
   113               let val args = map (fn i =>
   114                 Pretty.str ("x" ^ string_of_int i)) (1 upto length Ts)
   115               in ("  | ", Pretty.blk (4,
   116                 [Pretty.str prfx, mk_term_of gr module' false T, Pretty.brk 1,
   117                  if null Ts then Pretty.str (snd (get_const_id cname gr))
   118                  else parens (Pretty.block
   119                    [Pretty.str (snd (get_const_id cname gr)),
   120                     Pretty.brk 1, mk_tuple args]),
   121                  Pretty.str " =", Pretty.brk 1] @
   122                  List.concat (separate [Pretty.str " $", Pretty.brk 1]
   123                    ([Pretty.str ("Const (\"" ^ cname ^ "\","), Pretty.brk 1,
   124                      mk_type false (Ts ---> T), Pretty.str ")"] ::
   125                     map (fn (x, U) => [Pretty.block [mk_term_of gr module' false U,
   126                       Pretty.brk 1, x]]) (args ~~ Ts)))))
   127               end) (prfx, cs')
   128           in eqs @ rest end;
   129 
   130     fun mk_gen_of_def gr prfx [] = []
   131       | mk_gen_of_def gr prfx ((i, (tname, dts, cs)) :: xs) =
   132           let
   133             val tvs = map DatatypeAux.dest_DtTFree dts;
   134             val sorts = map (rpair []) tvs;
   135             val (cs1, cs2) =
   136               List.partition (exists DatatypeAux.is_rec_type o snd) cs;
   137             val SOME (cname, _) = find_nonempty descr [i] i;
   138 
   139             fun mk_delay p = Pretty.block
   140               [Pretty.str "fn () =>", Pretty.brk 1, p];
   141 
   142             fun mk_constr s b (cname, dts) =
   143               let
   144                 val gs = map (fn dt => mk_app false (mk_gen gr module' false rtnames s
   145                     (DatatypeAux.typ_of_dtyp descr sorts dt))
   146                   [Pretty.str (if b andalso DatatypeAux.is_rec_type dt then "0"
   147                      else "j")]) dts;
   148                 val (_, id) = get_const_id cname gr
   149               in case gs of
   150                   _ :: _ :: _ => Pretty.block
   151                     [Pretty.str id, Pretty.brk 1, mk_tuple gs]
   152                 | _ => mk_app false (Pretty.str id) (map parens gs)
   153               end;
   154 
   155             fun mk_choice [c] = mk_constr "(i-1)" false c
   156               | mk_choice cs = Pretty.block [Pretty.str "one_of",
   157                   Pretty.brk 1, Pretty.blk (1, Pretty.str "[" ::
   158                   List.concat (separate [Pretty.str ",", Pretty.fbrk]
   159                     (map (single o mk_delay o mk_constr "(i-1)" false) cs)) @
   160                   [Pretty.str "]"]), Pretty.brk 1, Pretty.str "()"];
   161 
   162             val gs = map (Pretty.str o suffix "G" o strip_tname) tvs;
   163             val gen_name = "gen_" ^ snd (get_type_id tname gr)
   164 
   165           in
   166             Pretty.blk (4, separate (Pretty.brk 1) 
   167                 (Pretty.str (prfx ^ gen_name ^
   168                    (if null cs1 then "" else "'")) :: gs @
   169                  (if null cs1 then [] else [Pretty.str "i"]) @
   170                  [Pretty.str "j"]) @
   171               [Pretty.str " =", Pretty.brk 1] @
   172               (if not (null cs1) andalso not (null cs2)
   173                then [Pretty.str "frequency", Pretty.brk 1,
   174                  Pretty.blk (1, [Pretty.str "[",
   175                    mk_tuple [Pretty.str "i", mk_delay (mk_choice cs1)],
   176                    Pretty.str ",", Pretty.fbrk,
   177                    mk_tuple [Pretty.str "1", mk_delay (mk_choice cs2)],
   178                    Pretty.str "]"]), Pretty.brk 1, Pretty.str "()"]
   179                else if null cs2 then
   180                  [Pretty.block [Pretty.str "(case", Pretty.brk 1,
   181                    Pretty.str "i", Pretty.brk 1, Pretty.str "of",
   182                    Pretty.brk 1, Pretty.str "0 =>", Pretty.brk 1,
   183                    mk_constr "0" true (cname, valOf (AList.lookup (op =) cs cname)),
   184                    Pretty.brk 1, Pretty.str "| _ =>", Pretty.brk 1,
   185                    mk_choice cs1, Pretty.str ")"]]
   186                else [mk_choice cs2])) ::
   187             (if null cs1 then []
   188              else [Pretty.blk (4, separate (Pretty.brk 1) 
   189                  (Pretty.str ("and " ^ gen_name) :: gs @ [Pretty.str "i"]) @
   190                [Pretty.str " =", Pretty.brk 1] @
   191                separate (Pretty.brk 1) (Pretty.str (gen_name ^ "'") :: gs @
   192                  [Pretty.str "i", Pretty.str "i"]))]) @
   193             mk_gen_of_def gr "and " xs
   194           end
   195 
   196   in
   197     ((add_edge_acyclic (node_id, dep) gr
   198         handle Graph.CYCLES _ => gr) handle Graph.UNDEF _ =>
   199          let
   200            val gr1 = add_edge (node_id, dep)
   201              (new_node (node_id, (NONE, "", "")) gr);
   202            val (gr2, dtdef) = mk_dtdef gr1 "datatype " descr';
   203          in
   204            map_node node_id (K (NONE, module',
   205              Pretty.string_of (Pretty.blk (0, separate Pretty.fbrk dtdef @
   206                [Pretty.str ";"])) ^ "\n\n" ^
   207              (if "term_of" mem !mode then
   208                 Pretty.string_of (Pretty.blk (0, separate Pretty.fbrk
   209                   (mk_term_of_def gr2 "fun " descr') @ [Pretty.str ";"])) ^ "\n\n"
   210               else "") ^
   211              (if "test" mem !mode then
   212                 Pretty.string_of (Pretty.blk (0, separate Pretty.fbrk
   213                   (mk_gen_of_def gr2 "fun " descr') @ [Pretty.str ";"])) ^ "\n\n"
   214               else ""))) gr2
   215          end,
   216      module')
   217   end;
   218 
   219 
   220 (**** case expressions ****)
   221 
   222 fun pretty_case thy defs gr dep module brack constrs (c as Const (_, T)) ts =
   223   let val i = length constrs
   224   in if length ts <= i then
   225        invoke_codegen thy defs dep module brack (gr, eta_expand c ts (i+1))
   226     else
   227       let
   228         val ts1 = Library.take (i, ts);
   229         val t :: ts2 = Library.drop (i, ts);
   230         val names = foldr add_term_names
   231           (map (fst o fst o dest_Var) (foldr add_term_vars [] ts1)) ts1;
   232         val (Ts, dT) = split_last (Library.take (i+1, fst (strip_type T)));
   233 
   234         fun pcase gr [] [] [] = ([], gr)
   235           | pcase gr ((cname, cargs)::cs) (t::ts) (U::Us) =
   236               let
   237                 val j = length cargs;
   238                 val xs = Name.variant_list names (replicate j "x");
   239                 val Us' = Library.take (j, fst (strip_type U));
   240                 val frees = map Free (xs ~~ Us');
   241                 val (gr0, cp) = invoke_codegen thy defs dep module false
   242                   (gr, list_comb (Const (cname, Us' ---> dT), frees));
   243                 val t' = Envir.beta_norm (list_comb (t, frees));
   244                 val (gr1, p) = invoke_codegen thy defs dep module false (gr0, t');
   245                 val (ps, gr2) = pcase gr1 cs ts Us;
   246               in
   247                 ([Pretty.block [cp, Pretty.str " =>", Pretty.brk 1, p]] :: ps, gr2)
   248               end;
   249 
   250         val (ps1, gr1) = pcase gr constrs ts1 Ts;
   251         val ps = List.concat (separate [Pretty.brk 1, Pretty.str "| "] ps1);
   252         val (gr2, p) = invoke_codegen thy defs dep module false (gr1, t);
   253         val (gr3, ps2) = foldl_map (invoke_codegen thy defs dep module true) (gr2, ts2)
   254       in (gr3, (if not (null ts2) andalso brack then parens else I)
   255         (Pretty.block (separate (Pretty.brk 1)
   256           (Pretty.block ([Pretty.str "(case ", p, Pretty.str " of",
   257              Pretty.brk 1] @ ps @ [Pretty.str ")"]) :: ps2))))
   258       end
   259   end;
   260 
   261 
   262 (**** constructors ****)
   263 
   264 fun pretty_constr thy defs gr dep module brack args (c as Const (s, T)) ts =
   265   let val i = length args
   266   in if i > 1 andalso length ts < i then
   267       invoke_codegen thy defs dep module brack (gr, eta_expand c ts i)
   268      else
   269        let
   270          val id = mk_qual_id module (get_const_id s gr);
   271          val (gr', ps) = foldl_map
   272            (invoke_codegen thy defs dep module (i = 1)) (gr, ts);
   273        in (case args of
   274           _ :: _ :: _ => (gr', (if brack then parens else I)
   275             (Pretty.block [Pretty.str id, Pretty.brk 1, mk_tuple ps]))
   276         | _ => (gr', mk_app brack (Pretty.str id) ps))
   277        end
   278   end;
   279 
   280 
   281 (**** code generators for terms and types ****)
   282 
   283 fun datatype_codegen thy defs gr dep module brack t = (case strip_comb t of
   284    (c as Const (s, T), ts) =>
   285      (case DatatypePackage.datatype_of_case thy s of
   286         SOME {index, descr, ...} =>
   287           if is_some (get_assoc_code thy (s, T)) then NONE else
   288           SOME (pretty_case thy defs gr dep module brack
   289             (#3 (the (AList.lookup op = descr index))) c ts)
   290       | NONE => case (DatatypePackage.datatype_of_constr thy s, strip_type T) of
   291         (SOME {index, descr, ...}, (_, U as Type _)) =>
   292           if is_some (get_assoc_code thy (s, T)) then NONE else
   293           let val SOME args = AList.lookup op =
   294             (#3 (the (AList.lookup op = descr index))) s
   295           in
   296             SOME (pretty_constr thy defs
   297               (fst (invoke_tycodegen thy defs dep module false (gr, U)))
   298               dep module brack args c ts)
   299           end
   300       | _ => NONE)
   301  | _ => NONE);
   302 
   303 fun datatype_tycodegen thy defs gr dep module brack (Type (s, Ts)) =
   304       (case DatatypePackage.get_datatype thy s of
   305          NONE => NONE
   306        | SOME {descr, ...} =>
   307            if is_some (get_assoc_type thy s) then NONE else
   308            let
   309              val (gr', ps) = foldl_map
   310                (invoke_tycodegen thy defs dep module false) (gr, Ts);
   311              val (gr'', module') = add_dt_defs thy defs dep module gr' descr;
   312              val (gr''', tyid) = mk_type_id module' s gr''
   313            in SOME (gr''',
   314              Pretty.block ((if null Ts then [] else
   315                [mk_tuple ps, Pretty.str " "]) @
   316                [Pretty.str (mk_qual_id module tyid)]))
   317            end)
   318   | datatype_tycodegen _ _ _ _ _ _ _ = NONE;
   319 
   320 
   321 (** datatypes for code 2nd generation **)
   322 
   323 fun dtyp_of_case_const thy c =
   324   Option.map (fn {descr, index, ...} => #1 (the (AList.lookup op = descr index)))
   325     (DatatypePackage.datatype_of_case thy c);
   326 
   327 fun dest_case_app cs ts tys =
   328   let
   329     val names = (Name.make_context o map fst) (fold Term.add_tfrees ts []);
   330     val abs = Name.names names "a" (Library.drop (length ts, tys));
   331     val (ts', t) = split_last (ts @ map Free abs);
   332     val (tys', sty) = split_last tys;
   333     fun dest_case ((c, tys_decl), ty) t =
   334       let
   335         val (vs, t') = Term.strip_abs_eta (length tys_decl) t;
   336         val c' = list_comb (Const (c, map snd vs ---> sty), map Free vs);
   337       in case t'
   338        of Const ("HOL.undefined", _) => NONE
   339         | _ => SOME (c', t')
   340       end;
   341   in (abs, ((t, sty), map2 dest_case (cs ~~ tys') ts' |> map_filter I)) end;
   342 
   343 fun dest_case_expr thy t =
   344   case strip_comb t
   345    of (Const (c, ty), ts) =>
   346         (case dtyp_of_case_const thy c
   347          of SOME dtco =>
   348               let val (vs, cs) = (the o DatatypePackage.get_datatype_spec thy) dtco;
   349               in SOME (dest_case_app cs ts (Library.take (length cs + 1, (fst o strip_type) ty))) end
   350           | _ => NONE)
   351     | _ => NONE;
   352 
   353 fun mk_distinct cos =
   354   let
   355     fun sym_product [] = []
   356       | sym_product (x::xs) = map (pair x) xs @ sym_product xs;
   357     fun mk_co_args (co, tys) ctxt =
   358       let
   359         val names = Name.invents ctxt "a" (length tys);
   360         val ctxt' = fold Name.declare names ctxt;
   361         val vs = map2 (curry Free) names tys;
   362       in (vs, ctxt') end;
   363     fun mk_dist ((co1, tys1), (co2, tys2)) =
   364       let
   365         val ((xs1, xs2), _) = Name.context
   366           |> mk_co_args (co1, tys1)
   367           ||>> mk_co_args (co2, tys2);
   368         val prem = HOLogic.mk_eq
   369           (list_comb (co1, xs1), list_comb (co2, xs2));
   370         val t = HOLogic.mk_not prem;
   371       in HOLogic.mk_Trueprop t end;
   372   in map mk_dist (sym_product cos) end;
   373 
   374 local
   375   val not_sym = thm "HOL.not_sym";
   376   val not_false_true = iffD2 OF [nth (thms "HOL.simp_thms") 7, TrueI];
   377   val refl = thm "refl";
   378   val eqTrueI = thm "eqTrueI";
   379 in
   380 
   381 fun get_eq_datatype thy dtco =
   382   let
   383     val SOME (vs, cs) = DatatypePackage.get_datatype_spec thy dtco;
   384     fun mk_triv_inject co =
   385       let
   386         val ct' = Thm.cterm_of thy
   387           (Const (co, Type (dtco, map (fn (v, sort) => TVar ((v, 0), sort)) vs)))
   388         val cty' = Thm.ctyp_of_term ct';
   389         val SOME (ct, cty) = fold_aterms (fn Var (v, ty) =>
   390           (K o SOME) (Thm.cterm_of thy (Var (v, Thm.typ_of cty')), Thm.ctyp_of thy ty) | _ => I)
   391           (Thm.prop_of refl) NONE;
   392       in eqTrueI OF [Thm.instantiate ([(cty, cty')], [(ct, ct')]) refl] end;
   393     val inject1 = map_filter (fn (co, []) => SOME (mk_triv_inject co) | _ => NONE) cs
   394     val inject2 = (#inject o DatatypePackage.the_datatype thy) dtco;
   395     val ctxt = ProofContext.init thy;
   396     val simpset = Simplifier.context ctxt
   397       (MetaSimplifier.empty_ss addsimprocs [distinct_simproc]);
   398     val cos = map (fn (co, tys) =>
   399         (Const (co, tys ---> Type (dtco, map TFree vs)), tys)) cs;
   400     val tac = ALLGOALS (simp_tac simpset)
   401       THEN ALLGOALS (ProofContext.fact_tac [not_false_true, TrueI]);
   402     val distinct =
   403       mk_distinct cos
   404       |> map (fn t => Goal.prove_global thy [] [] t (K tac))
   405       |> (fn thms => thms @ map (fn thm => not_sym OF [thm]) thms)
   406   in inject1 @ inject2 @ distinct end;
   407 
   408 end;
   409 
   410 fun get_case_cert thy tyco =
   411   let
   412     val raw_thms =
   413       (#case_rewrites o DatatypePackage.the_datatype thy) tyco;
   414     val thms as hd_thm :: _ = raw_thms
   415       |> Conjunction.intr_balanced
   416       |> Drule.unvarify
   417       |> Conjunction.elim_balanced (length raw_thms)
   418       |> map Simpdata.mk_meta_eq
   419       |> map Drule.zero_var_indexes
   420     val params = fold_aterms (fn (Free (v, _)) => insert (op =) v
   421       | _ => I) (Thm.prop_of hd_thm) [];
   422     val rhs = hd_thm
   423       |> Thm.prop_of
   424       |> Logic.dest_equals
   425       |> fst
   426       |> Term.strip_comb
   427       |> apsnd (fst o split_last)
   428       |> list_comb;
   429     val lhs = Free (Name.variant params "case", Term.fastype_of rhs);
   430     val asm = (Thm.cterm_of thy o Logic.mk_equals) (lhs, rhs);
   431   in
   432     thms
   433     |> Conjunction.intr_balanced
   434     |> MetaSimplifier.rewrite_rule [(Thm.symmetric o Thm.assume) asm]
   435     |> Thm.implies_intr asm
   436     |> Thm.generalize ([], params) 0
   437     |> Thm.varifyT
   438   end;
   439 
   440 
   441 
   442 (** codetypes for code 2nd generation **)
   443 
   444 (* abstraction over datatypes vs. type copies *)
   445 
   446 fun codetypes_dependency thy =
   447   let
   448     val names =
   449       map (rpair true) (Symtab.keys (DatatypePackage.get_datatypes thy))
   450         @ map (rpair false) (TypecopyPackage.get_typecopies thy);
   451     fun add_node (name, is_dt) =
   452       let
   453         fun add_tycos (Type (tyco, tys)) = insert (op =) tyco #> fold add_tycos tys
   454           | add_tycos _ = I;
   455         val tys = if is_dt then
   456             (maps snd o snd o the o DatatypePackage.get_datatype_spec thy) name
   457           else
   458             [(#typ o the o TypecopyPackage.get_typecopy_info thy) name]
   459         val deps = (filter (AList.defined (op =) names) o maps (fn ty =>
   460           add_tycos ty [])) tys;
   461       in
   462         Graph.default_node (name, ())
   463         #> fold (fn name' =>
   464              Graph.default_node (name', ())
   465              #> Graph.add_edge (name', name)
   466            ) deps
   467       end
   468   in
   469     Graph.empty
   470     |> fold add_node names
   471     |> Graph.strong_conn
   472     |> map (AList.make (the o AList.lookup (op =) names))
   473   end;
   474 
   475 fun get_spec thy (dtco, true) =
   476       (the o DatatypePackage.get_datatype_spec thy) dtco
   477   | get_spec thy (tyco, false) =
   478       TypecopyPackage.get_spec thy tyco;
   479 
   480 local
   481   fun get_eq_thms thy tyco = case DatatypePackage.get_datatype thy tyco
   482    of SOME _ => get_eq_datatype thy tyco
   483     | NONE => [TypecopyPackage.get_eq thy tyco];
   484   fun constrain_op_eq_thms thy thms =
   485     let
   486       fun add_eq (Const ("op =", ty)) =
   487             fold (insert (eq_fst (op =))) (Term.add_tvarsT ty [])
   488         | add_eq _ =
   489             I
   490       val eqs = fold (fold_aterms add_eq o Thm.prop_of) thms [];
   491       val instT = map (fn (v_i, sort) =>
   492         (Thm.ctyp_of thy (TVar (v_i, sort)),
   493            Thm.ctyp_of thy (TVar (v_i, Sorts.inter_sort (Sign.classes_of thy)
   494              (sort, [HOLogic.class_eq]))))) eqs;
   495     in
   496       thms
   497       |> map (Thm.instantiate (instT, []))
   498     end;
   499 in
   500   fun get_eq thy tyco =
   501     get_eq_thms thy tyco
   502     |> maps ((#mk o #mk_rews o snd o MetaSimplifier.rep_ss o Simplifier.simpset_of) thy)
   503     |> constrain_op_eq_thms thy
   504 end;
   505 
   506 type hook = (string * (bool * ((string * sort) list * (string * typ list) list))) list
   507   -> theory -> theory;
   508 
   509 fun add_codetypes_hook_bootstrap hook thy =
   510   let
   511     fun add_spec thy (tyco, is_dt) =
   512       (tyco, (is_dt, get_spec thy (tyco, is_dt)));
   513     fun datatype_hook dtcos thy =
   514       hook (map (add_spec thy) (map (rpair true) dtcos)) thy;
   515     fun typecopy_hook ((tyco, _)) thy =
   516       hook ([(tyco, (false, TypecopyPackage.get_spec thy tyco))]) thy;
   517   in
   518     thy
   519     |> fold hook ((map o map) (add_spec thy) (codetypes_dependency thy))
   520     |> DatatypeHooks.add datatype_hook
   521     |> TypecopyPackage.add_hook typecopy_hook
   522   end;
   523 
   524 fun the_codetypes_mut_specs thy ([(tyco, is_dt)]) =
   525       let
   526         val (vs, cs) = get_spec thy (tyco, is_dt)
   527       in (vs, [(tyco, (is_dt, cs))]) end
   528   | the_codetypes_mut_specs thy (tycos' as (tyco, true) :: _) =
   529       let
   530         val tycos = map fst tycos';
   531         val tycos'' = (map (#1 o snd) o #descr o DatatypePackage.the_datatype thy) tyco;
   532         val _ = if gen_subset (op =) (tycos, tycos'') then () else
   533           error ("type constructors are not mutually recursive: " ^ (commas o map quote) tycos);
   534         val (vs::_, css) = split_list (map (the o DatatypePackage.get_datatype_spec thy) tycos);
   535       in (vs, map2 (fn (tyco, is_dt) => fn cs => (tyco, (is_dt, cs))) tycos' css) end;
   536 
   537 
   538 (* registering code types in code generator *)
   539 
   540 fun add_datatype_spec (tyco, (vs, cos)) thy =
   541   let
   542     val cs = map (fn (c, tys) => (c, tys ---> Type (tyco, map TFree vs))) cos;
   543   in try (Code.add_datatype cs) thy |> the_default thy end;
   544 
   545 val codetype_hook =
   546   fold (fn (dtco, (_, spec)) => add_datatype_spec (dtco, spec));
   547 
   548 
   549 (* instrumentalizing the sort algebra *)
   550 
   551 fun get_codetypes_arities thy tycos sort =
   552   let
   553     val pp = Sign.pp thy;
   554     val algebra = Sign.classes_of thy;
   555     val (vs_proto, css_proto) = the_codetypes_mut_specs thy tycos;
   556     val vs = map (fn (v, vsort) => (v, Sorts.inter_sort algebra (vsort, sort))) vs_proto;
   557     val css = map (fn (tyco, (_, cs)) => (tyco, cs)) css_proto;
   558     val algebra' = algebra
   559       |> fold (fn (tyco, _) =>
   560            Sorts.add_arities pp (tyco, map (fn class => (class, map snd vs)) sort)) css;
   561     fun typ_sort_inst ty = CodeUnit.typ_sort_inst algebra' (Logic.varifyT ty, sort);
   562     val venv = Vartab.empty
   563       |> fold (fn (v, sort) => Vartab.update_new ((v, 0), sort)) vs
   564       |> fold (fn (_, cs) => fold (fn (_, tys) => fold typ_sort_inst tys) cs) css;
   565     fun inst (v, _) = (v, (the o Vartab.lookup venv) (v, 0));
   566     val vs' = map inst vs;
   567     fun mk_arity tyco = (tyco, map snd vs', sort);
   568     fun mk_cons tyco (c, tys) =
   569       let
   570         val tys' = (map o Term.map_type_tfree) (TFree o inst) tys;
   571         val ts = Name.names Name.context "a" tys';
   572         val ty = (tys' ---> Type (tyco, map TFree vs'));
   573       in list_comb (Const (c, ty), map Free ts) end;
   574   in
   575     map (fn (tyco, cs) => (tyco, (mk_arity tyco, map (mk_cons tyco) cs))) css |> SOME
   576   end handle Class_Error => NONE;
   577 
   578 fun prove_codetypes_arities tac tycos sort f after_qed thy =
   579   case get_codetypes_arities thy tycos sort
   580    of NONE => thy
   581     | SOME insts => let
   582         fun proven (tyco, asorts, sort) =
   583           Sorts.of_sort (Sign.classes_of thy)
   584             (Type (tyco, map TFree (Name.names Name.context "'a" asorts)), sort);
   585         val (arities, css) = (split_list o map_filter
   586           (fn (tyco, (arity, cs)) => if proven arity
   587             then NONE else SOME (arity, (tyco, cs)))) insts;
   588       in
   589         thy
   590         |> not (null arities) ? (
   591             f arities css
   592             #-> (fn defs =>
   593               Class.prove_instance_arity tac arities defs
   594             #-> (fn defs =>
   595               after_qed arities css defs)))
   596       end;
   597 
   598 
   599 (* operational equality *)
   600 
   601 fun eq_hook specs =
   602   let
   603     fun add_eq_thms (dtco, (_, (vs, cs))) thy =
   604       let
   605         val thy_ref = Theory.check_thy thy;
   606         val const = Class.inst_const thy ("op =", dtco);
   607         val get_thms = (fn () => get_eq (Theory.deref thy_ref) dtco |> rev);
   608       in
   609         Code.add_funcl (const, Susp.delay get_thms) thy
   610       end;
   611   in
   612     prove_codetypes_arities (Class.intro_classes_tac [])
   613       (map (fn (tyco, (is_dt, _)) => (tyco, is_dt)) specs)
   614       [HOLogic.class_eq] ((K o K o pair) []) ((K o K o K) (fold add_eq_thms specs))
   615   end;
   616 
   617 
   618 
   619 (** theory setup **)
   620 
   621 fun add_datatype_case_const dtco thy =
   622   let
   623     val {case_name, index, descr, ...} = DatatypePackage.the_datatype thy dtco;
   624   in
   625     CodePackage.add_appconst (case_name, CodePackage.appgen_case dest_case_expr) thy
   626   end;
   627 
   628 fun add_datatype_case_defs dtco thy =
   629   let
   630     val {case_rewrites, ...} = DatatypePackage.the_datatype thy dtco
   631   in
   632     fold_rev (Code.add_func true) case_rewrites thy
   633   end;
   634 
   635 val setup = 
   636   add_codegen "datatype" datatype_codegen
   637   #> add_tycodegen "datatype" datatype_tycodegen 
   638   #> DatatypeHooks.add (fold add_datatype_case_const)
   639   #> DatatypeHooks.add (fold add_datatype_case_defs)
   640 
   641 val setup_hooks =
   642   add_codetypes_hook_bootstrap codetype_hook
   643   #> add_codetypes_hook_bootstrap eq_hook
   644 
   645 
   646 end;