src/Pure/Tools/find_theorems.ML
 author wenzelm Wed Aug 11 17:50:29 2010 +0200 (2010-08-11) changeset 38334 c677c2c1d333 parent 36953 2af1ad9aa1a3 child 38335 630f379f2660 permissions -rw-r--r--
simplified/unified command setup;
```     1 (*  Title:      Pure/Tools/find_theorems.ML
```
```     2     Author:     Rafal Kolanski and Gerwin Klein, NICTA
```
```     3
```
```     4 Retrieve theorems from proof context.
```
```     5 *)
```
```     6
```
```     7 signature FIND_THEOREMS =
```
```     8 sig
```
```     9   datatype 'term criterion =
```
```    10     Name of string | Intro | IntroIff | Elim | Dest | Solves | Simp of 'term |
```
```    11     Pattern of 'term
```
```    12   val tac_limit: int Unsynchronized.ref
```
```    13   val limit: int Unsynchronized.ref
```
```    14   val find_theorems: Proof.context -> thm option -> int option -> bool ->
```
```    15     (bool * string criterion) list -> int option * (Facts.ref * thm) list
```
```    16   val pretty_thm: Proof.context -> Facts.ref * thm -> Pretty.T
```
```    17   val print_theorems: Proof.context -> thm option -> int option -> bool ->
```
```    18     (bool * string criterion) list -> unit
```
```    19 end;
```
```    20
```
```    21 structure Find_Theorems: FIND_THEOREMS =
```
```    22 struct
```
```    23
```
```    24 (** search criteria **)
```
```    25
```
```    26 datatype 'term criterion =
```
```    27   Name of string | Intro | IntroIff | Elim | Dest | Solves | Simp of 'term |
```
```    28   Pattern of 'term;
```
```    29
```
```    30 fun apply_dummies tm =
```
```    31   let
```
```    32     val (xs, _) = Term.strip_abs tm;
```
```    33     val tm' = Term.betapplys (tm, map (Term.dummy_pattern o #2) xs);
```
```    34   in #1 (Term.replace_dummy_patterns tm' 1) end;
```
```    35
```
```    36 fun parse_pattern ctxt nm =
```
```    37   let
```
```    38     val consts = ProofContext.consts_of ctxt;
```
```    39     val nm' =
```
```    40       (case Syntax.parse_term ctxt nm of
```
```    41         Const (c, _) => c
```
```    42       | _ => Consts.intern consts nm);
```
```    43   in
```
```    44     (case try (Consts.the_abbreviation consts) nm' of
```
```    45       SOME (_, rhs) => apply_dummies (ProofContext.expand_abbrevs ctxt rhs)
```
```    46     | NONE => ProofContext.read_term_pattern ctxt nm)
```
```    47   end;
```
```    48
```
```    49 fun read_criterion _ (Name name) = Name name
```
```    50   | read_criterion _ Intro = Intro
```
```    51   | read_criterion _ IntroIff = IntroIff
```
```    52   | read_criterion _ Elim = Elim
```
```    53   | read_criterion _ Dest = Dest
```
```    54   | read_criterion _ Solves = Solves
```
```    55   | read_criterion ctxt (Simp str) = Simp (ProofContext.read_term_pattern ctxt str)
```
```    56   | read_criterion ctxt (Pattern str) = Pattern (parse_pattern ctxt str);
```
```    57
```
```    58 fun pretty_criterion ctxt (b, c) =
```
```    59   let
```
```    60     fun prfx s = if b then s else "-" ^ s;
```
```    61   in
```
```    62     (case c of
```
```    63       Name name => Pretty.str (prfx "name: " ^ quote name)
```
```    64     | Intro => Pretty.str (prfx "intro")
```
```    65     | IntroIff => Pretty.str (prfx "introiff")
```
```    66     | Elim => Pretty.str (prfx "elim")
```
```    67     | Dest => Pretty.str (prfx "dest")
```
```    68     | Solves => Pretty.str (prfx "solves")
```
```    69     | Simp pat => Pretty.block [Pretty.str (prfx "simp:"), Pretty.brk 1,
```
```    70         Pretty.quote (Syntax.pretty_term ctxt (Term.show_dummy_patterns pat))]
```
```    71     | Pattern pat => Pretty.enclose (prfx " \"") "\""
```
```    72         [Syntax.pretty_term ctxt (Term.show_dummy_patterns pat)])
```
```    73   end;
```
```    74
```
```    75
```
```    76
```
```    77 (** search criterion filters **)
```
```    78
```
```    79 (*generated filters are to be of the form
```
```    80   input: (Facts.ref * thm)
```
```    81   output: (p:int, s:int) option, where
```
```    82     NONE indicates no match
```
```    83     p is the primary sorting criterion
```
```    84       (eg. number of assumptions in the theorem)
```
```    85     s is the secondary sorting criterion
```
```    86       (eg. size of the substitution for intro, elim and dest)
```
```    87   when applying a set of filters to a thm, fold results in:
```
```    88     (biggest p, sum of all s)
```
```    89   currently p and s only matter for intro, elim, dest and simp filters,
```
```    90   otherwise the default ordering is used.
```
```    91 *)
```
```    92
```
```    93
```
```    94 (* matching theorems *)
```
```    95
```
```    96 fun is_nontrivial thy = Term.is_Const o Term.head_of o Object_Logic.drop_judgment thy;
```
```    97
```
```    98 (*educated guesses on HOL*)  (* FIXME broken *)
```
```    99 val boolT = Type ("bool", []);
```
```   100 val iff_const = Const ("op =", boolT --> boolT --> boolT);
```
```   101
```
```   102 (*extract terms from term_src, refine them to the parts that concern us,
```
```   103   if po try match them against obj else vice versa.
```
```   104   trivial matches are ignored.
```
```   105   returns: smallest substitution size*)
```
```   106 fun is_matching_thm doiff (extract_terms, refine_term) ctxt po obj term_src =
```
```   107   let
```
```   108     val thy = ProofContext.theory_of ctxt;
```
```   109
```
```   110     fun check_match pat = Pattern.matches thy (if po then (pat, obj) else (obj, pat));
```
```   111     fun matches pat =
```
```   112       let
```
```   113         val jpat = Object_Logic.drop_judgment thy pat;
```
```   114         val c = Term.head_of jpat;
```
```   115         val pats =
```
```   116           if Term.is_Const c
```
```   117           then
```
```   118             if doiff andalso c = iff_const then
```
```   119               (pat :: map (Object_Logic.ensure_propT thy) (snd (strip_comb jpat)))
```
```   120                 |> filter (is_nontrivial thy)
```
```   121             else [pat]
```
```   122           else [];
```
```   123       in filter check_match pats end;
```
```   124
```
```   125     fun substsize pat =
```
```   126       let val (_, subst) =
```
```   127         Pattern.match thy (if po then (pat, obj) else (obj, pat)) (Vartab.empty, Vartab.empty)
```
```   128       in Vartab.fold (fn (_, (_, t)) => fn n => size_of_term t + n) subst 0 end;
```
```   129
```
```   130     fun bestmatch [] = NONE
```
```   131       | bestmatch xs = SOME (foldl1 Int.min xs);
```
```   132
```
```   133     val match_thm = matches o refine_term;
```
```   134   in
```
```   135     maps match_thm (extract_terms term_src)
```
```   136     |> map substsize
```
```   137     |> bestmatch
```
```   138   end;
```
```   139
```
```   140
```
```   141 (* filter_name *)
```
```   142
```
```   143 fun filter_name str_pat (thmref, _) =
```
```   144   if match_string str_pat (Facts.name_of_ref thmref)
```
```   145   then SOME (0, 0) else NONE;
```
```   146
```
```   147
```
```   148 (* filter intro/elim/dest/solves rules *)
```
```   149
```
```   150 fun filter_dest ctxt goal (_, thm) =
```
```   151   let
```
```   152     val extract_dest =
```
```   153      (fn thm => if Thm.no_prems thm then [] else [Thm.full_prop_of thm],
```
```   154       hd o Logic.strip_imp_prems);
```
```   155     val prems = Logic.prems_of_goal goal 1;
```
```   156
```
```   157     fun try_subst prem = is_matching_thm false extract_dest ctxt true prem thm;
```
```   158     val successful = prems |> map_filter try_subst;
```
```   159   in
```
```   160     (*if possible, keep best substitution (one with smallest size)*)
```
```   161     (*dest rules always have assumptions, so a dest with one
```
```   162       assumption is as good as an intro rule with none*)
```
```   163     if not (null successful)
```
```   164     then SOME (Thm.nprems_of thm - 1, foldl1 Int.min successful) else NONE
```
```   165   end;
```
```   166
```
```   167 fun filter_intro doiff ctxt goal (_, thm) =
```
```   168   let
```
```   169     val extract_intro = (single o Thm.full_prop_of, Logic.strip_imp_concl);
```
```   170     val concl = Logic.concl_of_goal goal 1;
```
```   171     val ss = is_matching_thm doiff extract_intro ctxt true concl thm;
```
```   172   in
```
```   173     if is_some ss then SOME (Thm.nprems_of thm, the ss) else NONE
```
```   174   end;
```
```   175
```
```   176 fun filter_elim ctxt goal (_, thm) =
```
```   177   if not (Thm.no_prems thm) then
```
```   178     let
```
```   179       val rule = Thm.full_prop_of thm;
```
```   180       val prems = Logic.prems_of_goal goal 1;
```
```   181       val goal_concl = Logic.concl_of_goal goal 1;
```
```   182       val rule_mp = hd (Logic.strip_imp_prems rule);
```
```   183       val rule_concl = Logic.strip_imp_concl rule;
```
```   184       fun combine t1 t2 = Const ("*combine*", dummyT --> dummyT) \$ (t1 \$ t2);
```
```   185       val rule_tree = combine rule_mp rule_concl;
```
```   186       fun goal_tree prem = combine prem goal_concl;
```
```   187       fun try_subst prem =
```
```   188         is_matching_thm false (single, I) ctxt true (goal_tree prem) rule_tree;
```
```   189       val successful = prems |> map_filter try_subst;
```
```   190     in
```
```   191       (*elim rules always have assumptions, so an elim with one
```
```   192         assumption is as good as an intro rule with none*)
```
```   193       if is_nontrivial (ProofContext.theory_of ctxt) (Thm.major_prem_of thm)
```
```   194         andalso not (null successful)
```
```   195       then SOME (Thm.nprems_of thm - 1, foldl1 Int.min successful) else NONE
```
```   196     end
```
```   197   else NONE
```
```   198
```
```   199 val tac_limit = Unsynchronized.ref 5;
```
```   200
```
```   201 fun filter_solves ctxt goal =
```
```   202   let
```
```   203     fun etacn thm i = Seq.take (! tac_limit) o etac thm i;
```
```   204     fun try_thm thm =
```
```   205       if Thm.no_prems thm then rtac thm 1 goal
```
```   206       else (etacn thm THEN_ALL_NEW (Goal.norm_hhf_tac THEN' Method.assm_tac ctxt)) 1 goal;
```
```   207   in
```
```   208     fn (_, thm) =>
```
```   209       if is_some (Seq.pull (try_thm thm))
```
```   210       then SOME (Thm.nprems_of thm, 0) else NONE
```
```   211   end;
```
```   212
```
```   213
```
```   214 (* filter_simp *)
```
```   215
```
```   216 fun filter_simp ctxt t (_, thm) =
```
```   217   let
```
```   218     val mksimps = Simplifier.mksimps (simpset_of ctxt);
```
```   219     val extract_simp =
```
```   220       (map Thm.full_prop_of o mksimps, #1 o Logic.dest_equals o Logic.strip_imp_concl);
```
```   221     val ss = is_matching_thm false extract_simp ctxt false t thm;
```
```   222   in
```
```   223     if is_some ss then SOME (Thm.nprems_of thm, the ss) else NONE
```
```   224   end;
```
```   225
```
```   226
```
```   227 (* filter_pattern *)
```
```   228
```
```   229 fun get_names t = Term.add_const_names t (Term.add_free_names t []);
```
```   230 fun get_thm_names (_, thm) = get_names (Thm.full_prop_of thm);
```
```   231
```
```   232 (*Including all constants and frees is only sound because
```
```   233   matching uses higher-order patterns. If full matching
```
```   234   were used, then constants that may be subject to
```
```   235   beta-reduction after substitution of frees should
```
```   236   not be included for LHS set because they could be
```
```   237   thrown away by the substituted function.
```
```   238   e.g. for (?F 1 2) do not include 1 or 2, if it were
```
```   239        possible for ?F to be (% x y. 3)
```
```   240   The largest possible set should always be included on
```
```   241   the RHS.*)
```
```   242
```
```   243 fun filter_pattern ctxt pat =
```
```   244   let
```
```   245     val pat_consts = get_names pat;
```
```   246
```
```   247     fun check (t, NONE) = check (t, SOME (get_thm_names t))
```
```   248       | check ((_, thm), c as SOME thm_consts) =
```
```   249          (if subset (op =) (pat_consts, thm_consts) andalso
```
```   250             Pattern.matches_subterm (ProofContext.theory_of ctxt) (pat, Thm.full_prop_of thm)
```
```   251           then SOME (0, 0) else NONE, c);
```
```   252   in check end;
```
```   253
```
```   254
```
```   255 (* interpret criteria as filters *)
```
```   256
```
```   257 local
```
```   258
```
```   259 fun err_no_goal c =
```
```   260   error ("Current goal required for " ^ c ^ " search criterion");
```
```   261
```
```   262 val fix_goal = Thm.prop_of;
```
```   263
```
```   264 fun filter_crit _ _ (Name name) = apfst (filter_name name)
```
```   265   | filter_crit _ NONE Intro = err_no_goal "intro"
```
```   266   | filter_crit _ NONE Elim = err_no_goal "elim"
```
```   267   | filter_crit _ NONE Dest = err_no_goal "dest"
```
```   268   | filter_crit _ NONE Solves = err_no_goal "solves"
```
```   269   | filter_crit ctxt (SOME goal) Intro = apfst (filter_intro false ctxt (fix_goal goal))
```
```   270   | filter_crit ctxt (SOME goal) IntroIff = apfst (filter_intro true ctxt (fix_goal goal))
```
```   271   | filter_crit ctxt (SOME goal) Elim = apfst (filter_elim ctxt (fix_goal goal))
```
```   272   | filter_crit ctxt (SOME goal) Dest = apfst (filter_dest ctxt (fix_goal goal))
```
```   273   | filter_crit ctxt (SOME goal) Solves = apfst (filter_solves ctxt goal)
```
```   274   | filter_crit ctxt _ (Simp pat) = apfst (filter_simp ctxt pat)
```
```   275   | filter_crit ctxt _ (Pattern pat) = filter_pattern ctxt pat;
```
```   276
```
```   277 fun opt_not x = if is_some x then NONE else SOME (0, 0);
```
```   278
```
```   279 fun opt_add (SOME (a, x)) (SOME (b, y)) = SOME (Int.max (a, b), x + y : int)
```
```   280   | opt_add _ _ = NONE;
```
```   281
```
```   282 fun app_filters thm =
```
```   283   let
```
```   284     fun app (NONE, _, _) = NONE
```
```   285       | app (SOME v, _, []) = SOME (v, thm)
```
```   286       | app (r, consts, f :: fs) =
```
```   287           let val (r', consts') = f (thm, consts)
```
```   288           in app (opt_add r r', consts', fs) end;
```
```   289   in app end;
```
```   290
```
```   291
```
```   292 in
```
```   293
```
```   294 fun filter_criterion ctxt opt_goal (b, c) =
```
```   295   (if b then I else (apfst opt_not)) o filter_crit ctxt opt_goal c;
```
```   296
```
```   297 fun sorted_filter filters thms =
```
```   298   let
```
```   299     fun eval_filters thm = app_filters thm (SOME (0, 0), NONE, filters);
```
```   300
```
```   301     (*filters return: (number of assumptions, substitution size) option, so
```
```   302       sort (desc. in both cases) according to number of assumptions first,
```
```   303       then by the substitution size*)
```
```   304     fun thm_ord (((p0, s0), _), ((p1, s1), _)) =
```
```   305       prod_ord int_ord int_ord ((p1, s1), (p0, s0));
```
```   306   in map_filter eval_filters thms |> sort thm_ord |> map #2 end;
```
```   307
```
```   308 fun lazy_filter filters =
```
```   309   let
```
```   310     fun lazy_match thms = Seq.make (fn () => first_match thms)
```
```   311
```
```   312     and first_match [] = NONE
```
```   313       | first_match (thm :: thms) =
```
```   314           (case app_filters thm (SOME (0, 0), NONE, filters) of
```
```   315             NONE => first_match thms
```
```   316           | SOME (_, t) => SOME (t, lazy_match thms));
```
```   317   in lazy_match end;
```
```   318
```
```   319 end;
```
```   320
```
```   321
```
```   322 (* removing duplicates, preferring nicer names, roughly n log n *)
```
```   323
```
```   324 local
```
```   325
```
```   326 val index_ord = option_ord (K EQUAL);
```
```   327 val hidden_ord = bool_ord o pairself Name_Space.is_hidden;
```
```   328 val qual_ord = int_ord o pairself (length o Long_Name.explode);
```
```   329 val txt_ord = int_ord o pairself size;
```
```   330
```
```   331 fun nicer_name (x, i) (y, j) =
```
```   332   (case hidden_ord (x, y) of EQUAL =>
```
```   333     (case index_ord (i, j) of EQUAL =>
```
```   334       (case qual_ord (x, y) of EQUAL => txt_ord (x, y) | ord => ord)
```
```   335     | ord => ord)
```
```   336   | ord => ord) <> GREATER;
```
```   337
```
```   338 fun rem_cdups nicer xs =
```
```   339   let
```
```   340     fun rem_c rev_seen [] = rev rev_seen
```
```   341       | rem_c rev_seen [x] = rem_c (x :: rev_seen) []
```
```   342       | rem_c rev_seen ((x as ((n, t), _)) :: (y as ((n', t'), _)) :: xs) =
```
```   343           if Thm.eq_thm_prop (t, t')
```
```   344           then rem_c rev_seen ((if nicer n n' then x else y) :: xs)
```
```   345           else rem_c (x :: rev_seen) (y :: xs)
```
```   346   in rem_c [] xs end;
```
```   347
```
```   348 in
```
```   349
```
```   350 fun nicer_shortest ctxt =
```
```   351   let
```
```   352     (* FIXME global name space!? *)
```
```   353     val space = Facts.space_of (PureThy.facts_of (ProofContext.theory_of ctxt));
```
```   354
```
```   355     val shorten =
```
```   356       Name_Space.extern_flags
```
```   357         {long_names = false, short_names = false, unique_names = false} space;
```
```   358
```
```   359     fun nicer (Facts.Named ((x, _), i)) (Facts.Named ((y, _), j)) =
```
```   360           nicer_name (shorten x, i) (shorten y, j)
```
```   361       | nicer (Facts.Fact _) (Facts.Named _) = true
```
```   362       | nicer (Facts.Named _) (Facts.Fact _) = false;
```
```   363   in nicer end;
```
```   364
```
```   365 fun rem_thm_dups nicer xs =
```
```   366   xs ~~ (1 upto length xs)
```
```   367   |> sort (Term_Ord.fast_term_ord o pairself (Thm.prop_of o #2 o #1))
```
```   368   |> rem_cdups nicer
```
```   369   |> sort (int_ord o pairself #2)
```
```   370   |> map #1;
```
```   371
```
```   372 end;
```
```   373
```
```   374
```
```   375 (* print_theorems *)
```
```   376
```
```   377 fun all_facts_of ctxt =
```
```   378   let
```
```   379     fun visible_facts facts =
```
```   380       Facts.dest_static [] facts
```
```   381       |> filter_out (Facts.is_concealed facts o #1);
```
```   382   in
```
```   383     maps Facts.selections
```
```   384      (visible_facts (PureThy.facts_of (ProofContext.theory_of ctxt)) @
```
```   385       visible_facts (ProofContext.facts_of ctxt))
```
```   386   end;
```
```   387
```
```   388 val limit = Unsynchronized.ref 40;
```
```   389
```
```   390 fun find_theorems ctxt opt_goal opt_limit rem_dups raw_criteria =
```
```   391   let
```
```   392     val assms =
```
```   393       ProofContext.get_fact ctxt (Facts.named "local.assms")
```
```   394         handle ERROR _ => [];
```
```   395     val add_prems = Seq.hd o TRY (Method.insert_tac assms 1);
```
```   396     val opt_goal' = Option.map add_prems opt_goal;
```
```   397
```
```   398     val criteria = map (apsnd (read_criterion ctxt)) raw_criteria;
```
```   399     val filters = map (filter_criterion ctxt opt_goal') criteria;
```
```   400
```
```   401     fun find_all facts =
```
```   402       let
```
```   403         val raw_matches = sorted_filter filters facts;
```
```   404
```
```   405         val matches =
```
```   406           if rem_dups
```
```   407           then rem_thm_dups (nicer_shortest ctxt) raw_matches
```
```   408           else raw_matches;
```
```   409
```
```   410         val len = length matches;
```
```   411         val lim = the_default (! limit) opt_limit;
```
```   412       in (SOME len, drop (Int.max (len - lim, 0)) matches) end;
```
```   413
```
```   414     val find =
```
```   415       if rem_dups orelse is_none opt_limit
```
```   416       then find_all
```
```   417       else pair NONE o Seq.list_of o Seq.take (the opt_limit) o lazy_filter filters;
```
```   418
```
```   419   in find (all_facts_of ctxt) end;
```
```   420
```
```   421
```
```   422 fun pretty_thm ctxt (thmref, thm) = Pretty.block
```
```   423   [Pretty.str (Facts.string_of_ref thmref), Pretty.str ":", Pretty.brk 1,
```
```   424     Display.pretty_thm ctxt thm];
```
```   425
```
```   426 fun print_theorems ctxt opt_goal opt_limit rem_dups raw_criteria =
```
```   427   let
```
```   428     val start = start_timing ();
```
```   429
```
```   430     val criteria = map (apsnd (read_criterion ctxt)) raw_criteria;
```
```   431     val (foundo, thms) = find_theorems ctxt opt_goal opt_limit rem_dups raw_criteria;
```
```   432     val returned = length thms;
```
```   433
```
```   434     val tally_msg =
```
```   435       (case foundo of
```
```   436         NONE => "displaying " ^ string_of_int returned ^ " theorems"
```
```   437       | SOME found =>
```
```   438           "found " ^ string_of_int found ^ " theorems" ^
```
```   439             (if returned < found
```
```   440              then " (" ^ string_of_int returned ^ " displayed)"
```
```   441              else ""));
```
```   442
```
```   443     val end_msg = " in " ^ Time.toString (#cpu (end_timing start)) ^ " secs";
```
```   444   in
```
```   445     Pretty.big_list "searched for:" (map (pretty_criterion ctxt) criteria)
```
```   446         :: Pretty.str "" ::
```
```   447      (if null thms then [Pretty.str ("nothing found" ^ end_msg)]
```
```   448       else
```
```   449         [Pretty.str (tally_msg ^ end_msg ^ ":"), Pretty.str ""] @
```
```   450         map (pretty_thm ctxt) thms)
```
```   451     |> Pretty.chunks |> Pretty.writeln
```
```   452   end;
```
```   453
```
```   454
```
```   455
```
```   456 (** command syntax **)
```
```   457
```
```   458 local
```
```   459
```
```   460 val criterion =
```
```   461   Parse.reserved "name" |-- Parse.!!! (Parse.\$\$\$ ":" |-- Parse.xname) >> Name ||
```
```   462   Parse.reserved "intro" >> K Intro ||
```
```   463   Parse.reserved "introiff" >> K IntroIff ||
```
```   464   Parse.reserved "elim" >> K Elim ||
```
```   465   Parse.reserved "dest" >> K Dest ||
```
```   466   Parse.reserved "solves" >> K Solves ||
```
```   467   Parse.reserved "simp" |-- Parse.!!! (Parse.\$\$\$ ":" |-- Parse.term) >> Simp ||
```
```   468   Parse.term >> Pattern;
```
```   469
```
```   470 val options =
```
```   471   Scan.optional
```
```   472     (Parse.\$\$\$ "(" |--
```
```   473       Parse.!!! (Scan.option Parse.nat -- Scan.optional (Parse.reserved "with_dups" >> K false) true
```
```   474         --| Parse.\$\$\$ ")")) (NONE, true);
```
```   475 in
```
```   476
```
```   477 val _ =
```
```   478   Outer_Syntax.improper_command "find_theorems" "print theorems meeting specified criteria"
```
```   479     Keyword.diag
```
```   480     (options -- Scan.repeat (((Scan.option Parse.minus >> is_none) -- criterion))
```
```   481       >> (fn ((opt_lim, rem_dups), spec) =>
```
```   482         Toplevel.no_timing o
```
```   483         Toplevel.keep (fn state =>
```
```   484           let
```
```   485             val ctxt = Toplevel.context_of state;
```
```   486             val opt_goal = try (Proof.simple_goal o Toplevel.proof_of) state |> Option.map #goal;
```
```   487           in print_theorems ctxt opt_goal opt_lim rem_dups spec end)));
```
```   488
```
```   489 end;
```
```   490
```
```   491 end;
```