src/Pure/Tools/find_theorems.ML
 author wenzelm Fri Feb 27 16:05:40 2009 +0100 (2009-02-27) changeset 30143 98a986b02022 parent 30142 8d6145694bb5 child 30186 1f836e949ac2 permissions -rw-r--r--
observe basic Isabelle/ML coding conventions;
1 (*  Title:      Pure/Tools/find_theorems.ML
2     Author:     Rafal Kolanski and Gerwin Klein, NICTA
4 Retrieve theorems from proof context.
5 *)
7 signature FIND_THEOREMS =
8 sig
9   val limit: int ref
10   val tac_limit: int ref
12   datatype 'term criterion =
13     Name of string | Intro | Elim | Dest | Solves | Simp of 'term |
14     Pattern of 'term
16   val find_theorems: Proof.context -> thm option -> bool ->
17     (bool * string criterion) list -> (Facts.ref * thm) list
19   val print_theorems: Proof.context -> thm option -> int option -> bool ->
20     (bool * string criterion) list -> unit
21 end;
23 structure FindTheorems: FIND_THEOREMS =
24 struct
26 (** search criteria **)
28 datatype 'term criterion =
29   Name of string | Intro | Elim | Dest | Solves | Simp of 'term |
30   Pattern of 'term;
32 fun read_criterion _ (Name name) = Name name
33   | read_criterion _ Intro = Intro
34   | read_criterion _ Elim = Elim
35   | read_criterion _ Dest = Dest
36   | read_criterion _ Solves = Solves
37   | read_criterion ctxt (Simp str) = Simp (ProofContext.read_term_pattern ctxt str)
38   | read_criterion ctxt (Pattern str) = Pattern (ProofContext.read_term_pattern ctxt str);
40 fun pretty_criterion ctxt (b, c) =
41   let
42     fun prfx s = if b then s else "-" ^ s;
43   in
44     (case c of
45       Name name => Pretty.str (prfx "name: " ^ quote name)
46     | Intro => Pretty.str (prfx "intro")
47     | Elim => Pretty.str (prfx "elim")
48     | Dest => Pretty.str (prfx "dest")
49     | Solves => Pretty.str (prfx "solves")
50     | Simp pat => Pretty.block [Pretty.str (prfx "simp:"), Pretty.brk 1,
51         Pretty.quote (Syntax.pretty_term ctxt (Term.show_dummy_patterns pat))]
52     | Pattern pat => Pretty.enclose (prfx " \"") "\""
53         [Syntax.pretty_term ctxt (Term.show_dummy_patterns pat)])
54   end;
58 (** search criterion filters **)
60 (*generated filters are to be of the form
61   input: (Facts.ref * thm)
62   output: (p:int, s:int) option, where
63     NONE indicates no match
64     p is the primary sorting criterion
65       (eg. number of assumptions in the theorem)
66     s is the secondary sorting criterion
67       (eg. size of the substitution for intro, elim and dest)
68   when applying a set of filters to a thm, fold results in:
69     (biggest p, sum of all s)
70   currently p and s only matter for intro, elim, dest and simp filters,
71   otherwise the default ordering is used.
72 *)
75 (* matching theorems *)
77 fun is_nontrivial thy = Term.is_Const o Term.head_of o ObjectLogic.drop_judgment thy;
79 (*extract terms from term_src, refine them to the parts that concern us,
80   if po try match them against obj else vice versa.
81   trivial matches are ignored.
82   returns: smallest substitution size*)
83 fun is_matching_thm (extract_terms, refine_term) ctxt po obj term_src =
84   let
85     val thy = ProofContext.theory_of ctxt;
87     fun matches pat =
88       is_nontrivial thy pat andalso
89       Pattern.matches thy (if po then (pat, obj) else (obj, pat));
91     fun substsize pat =
92       let val (_, subst) =
93         Pattern.match thy (if po then (pat, obj) else (obj, pat)) (Vartab.empty, Vartab.empty)
94       in Vartab.fold (fn (_, (_, t)) => fn n => size_of_term t + n) subst 0 end;
96     fun bestmatch [] = NONE
97      |  bestmatch xs = SOME (foldr1 Int.min xs);
99     val match_thm = matches o refine_term;
100   in
101     map (substsize o refine_term) (filter match_thm (extract_terms term_src))
102     |> bestmatch
103   end;
106 (* filter_name *)
108 fun filter_name str_pat (thmref, _) =
109   if match_string str_pat (Facts.name_of_ref thmref)
110   then SOME (0, 0) else NONE;
113 (* filter intro/elim/dest/solves rules *)
115 fun filter_dest ctxt goal (_, thm) =
116   let
117     val extract_dest =
118      (fn thm => if Thm.no_prems thm then [] else [Thm.full_prop_of thm],
119       hd o Logic.strip_imp_prems);
120     val prems = Logic.prems_of_goal goal 1;
122     fun try_subst prem = is_matching_thm extract_dest ctxt true prem thm;
123     val successful = prems |> map_filter try_subst;
124   in
125     (*if possible, keep best substitution (one with smallest size)*)
126     (*dest rules always have assumptions, so a dest with one
127       assumption is as good as an intro rule with none*)
128     if not (null successful)
129     then SOME (Thm.nprems_of thm - 1, foldr1 Int.min successful) else NONE
130   end;
132 fun filter_intro ctxt goal (_, thm) =
133   let
134     val extract_intro = (single o Thm.full_prop_of, Logic.strip_imp_concl);
135     val concl = Logic.concl_of_goal goal 1;
136     val ss = is_matching_thm extract_intro ctxt true concl thm;
137   in
138     if is_some ss then SOME (Thm.nprems_of thm, the ss) else NONE
139   end;
141 fun filter_elim ctxt goal (_, thm) =
142   if not (Thm.no_prems thm) then
143     let
144       val rule = Thm.full_prop_of thm;
145       val prems = Logic.prems_of_goal goal 1;
146       val goal_concl = Logic.concl_of_goal goal 1;
147       val rule_mp = hd (Logic.strip_imp_prems rule);
148       val rule_concl = Logic.strip_imp_concl rule;
149       fun combine t1 t2 = Const ("*combine*", dummyT --> dummyT) \$ (t1 \$ t2);
150       val rule_tree = combine rule_mp rule_concl;
151       fun goal_tree prem = combine prem goal_concl;
152       fun try_subst prem =
153         is_matching_thm (single, I) ctxt true (goal_tree prem) rule_tree;
154       val successful = prems |> map_filter try_subst;
155     in
156     (*elim rules always have assumptions, so an elim with one
157       assumption is as good as an intro rule with none*)
158       if is_nontrivial (ProofContext.theory_of ctxt) (Thm.major_prem_of thm)
159         andalso not (null successful)
160       then SOME (Thm.nprems_of thm - 1, foldr1 Int.min successful) else NONE
161     end
162   else NONE
164 val tac_limit = ref 5;
166 fun filter_solves ctxt goal =
167   let
168     val baregoal = Logic.get_goal (Thm.prop_of goal) 1;
170     fun etacn thm i = Seq.take (! tac_limit) o etac thm i;
171     fun try_thm thm =
172       if Thm.no_prems thm then rtac thm 1 goal
173       else (etacn thm THEN_ALL_NEW
174              (Goal.norm_hhf_tac THEN'
175                Method.assumption_tac ctxt)) 1 goal;
176   in
177     fn (_, thm) =>
178       if (is_some o Seq.pull o try_thm) thm
179       then SOME (Thm.nprems_of thm, 0) else NONE
180   end;
183 (* filter_simp *)
185 fun filter_simp ctxt t (_, thm) =
186   let
187     val (_, {mk_rews = {mk, ...}, ...}) =
188       Simplifier.rep_ss (Simplifier.local_simpset_of ctxt);
189     val extract_simp =
190       (map Thm.full_prop_of o mk, #1 o Logic.dest_equals o Logic.strip_imp_concl);
191     val ss = is_matching_thm extract_simp ctxt false t thm
192   in
193     if is_some ss then SOME (Thm.nprems_of thm, the ss) else NONE
194   end;
197 (* filter_pattern *)
199 fun get_names t = (Term.add_const_names t []) union (Term.add_free_names t []);
200 fun get_thm_names (_, thm) = get_names (Thm.full_prop_of thm);
202 (*Including all constants and frees is only sound because
203   matching uses higher-order patterns. If full matching
204   were used, then constants that may be subject to
205   beta-reduction after substitution of frees should
206   not be included for LHS set because they could be
207   thrown away by the substituted function.
208   e.g. for (?F 1 2) do not include 1 or 2, if it were
209        possible for ?F to be (% x y. 3)
210   The largest possible set should always be included on
211   the RHS.*)
213 fun filter_pattern ctxt pat =
214   let
215     val pat_consts = get_names pat;
217     fun check (t, NONE) = check (t, SOME (get_thm_names t))
218       | check ((_, thm), c as SOME thm_consts) =
219           (if pat_consts subset_string thm_consts
220               andalso (Pattern.matches_subterm (ProofContext.theory_of ctxt)
221                                                (pat, Thm.full_prop_of thm))
222            then SOME (0, 0) else NONE, c);
223   in check end;
226 (* interpret criteria as filters *)
228 local
230 fun err_no_goal c =
231   error ("Current goal required for " ^ c ^ " search criterion");
233 val fix_goal = Thm.prop_of;
234 val fix_goalo = Option.map fix_goal;
236 fun filter_crit _ _ (Name name) = apfst (filter_name name)
237   | filter_crit _ NONE Intro = err_no_goal "intro"
238   | filter_crit _ NONE Elim = err_no_goal "elim"
239   | filter_crit _ NONE Dest = err_no_goal "dest"
240   | filter_crit _ NONE Solves = err_no_goal "solves"
241   | filter_crit ctxt (SOME goal) Intro = apfst (filter_intro ctxt (fix_goal goal))
242   | filter_crit ctxt (SOME goal) Elim = apfst (filter_elim ctxt (fix_goal goal))
243   | filter_crit ctxt (SOME goal) Dest = apfst (filter_dest ctxt (fix_goal goal))
244   | filter_crit ctxt (SOME goal) Solves = apfst (filter_solves ctxt goal)
245   | filter_crit ctxt _ (Simp pat) = apfst (filter_simp ctxt pat)
246   | filter_crit ctxt _ (Pattern pat) = filter_pattern ctxt pat;
248 fun opt_not x = if is_some x then NONE else SOME (0, 0);
250 fun opt_add (SOME (a, x)) (SOME (b, y)) = SOME (Int.max (a, b), x + y : int)
251   | opt_add _ _ = NONE;
253 fun app_filters thm =
254   let
255     fun app (NONE, _, _) = NONE
256       | app (SOME v, consts, []) = SOME (v, thm)
257       | app (r, consts, f :: fs) =
258           let val (r', consts') = f (thm, consts)
259           in app (opt_add r r', consts', fs) end;
260   in app end;
262 in
264 fun filter_criterion ctxt opt_goal (b, c) =
265   (if b then I else (apfst opt_not)) o filter_crit ctxt opt_goal c;
267 fun all_filters filters thms =
268   let
269     fun eval_filters thm = app_filters thm (SOME (0, 0), NONE, filters);
271     (*filters return: (number of assumptions, substitution size) option, so
272       sort (desc. in both cases) according to number of assumptions first,
273       then by the substitution size*)
274     fun thm_ord (((p0, s0), _), ((p1, s1), _)) =
275       prod_ord int_ord int_ord ((p1, s1), (p0, s0));
276   in map_filter eval_filters thms |> sort thm_ord |> map #2 end;
278 end;
281 (* removing duplicates, preferring nicer names, roughly n log n *)
283 local
285 val index_ord = option_ord (K EQUAL);
286 val hidden_ord = bool_ord o pairself NameSpace.is_hidden;
287 val qual_ord = int_ord o pairself (length o NameSpace.explode);
288 val txt_ord = int_ord o pairself size;
290 fun nicer_name (x, i) (y, j) =
291   (case hidden_ord (x, y) of EQUAL =>
292     (case index_ord (i, j) of EQUAL =>
293       (case qual_ord (x, y) of EQUAL => txt_ord (x, y) | ord => ord)
294     | ord => ord)
295   | ord => ord) <> GREATER;
297 fun rem_cdups nicer xs =
298   let
299     fun rem_c rev_seen [] = rev rev_seen
300       | rem_c rev_seen [x] = rem_c (x :: rev_seen) []
301       | rem_c rev_seen ((x as ((n, t), _)) :: (y as ((n', t'), _)) :: xs) =
302         if Thm.eq_thm_prop (t, t')
303         then rem_c rev_seen ((if nicer n n' then x else y) :: xs)
304         else rem_c (x :: rev_seen) (y :: xs)
305   in rem_c [] xs end;
307 in
309 fun nicer_shortest ctxt =
310   let
311     val ns = ProofContext.theory_of ctxt
312              |> PureThy.facts_of
313              |> Facts.space_of;
315     val len_sort = sort (int_ord o (pairself size));
316     fun shorten s = (case len_sort (NameSpace.get_accesses ns s) of
317                        [] => s
318                      | s'::_ => s');
320     fun nicer (Facts.Named ((x, _), i)) (Facts.Named ((y, _), j)) =
321           nicer_name (shorten x, i) (shorten y, j)
322       | nicer (Facts.Fact _) (Facts.Named _) = true
323       | nicer (Facts.Named _) (Facts.Fact _) = false;
324   in nicer end;
326 fun rem_thm_dups nicer xs =
327   xs ~~ (1 upto length xs)
328   |> sort (TermOrd.fast_term_ord o pairself (Thm.prop_of o #2 o #1))
329   |> rem_cdups nicer
330   |> sort (int_ord o pairself #2)
331   |> map #1;
333 end;
336 (* print_theorems *)
338 fun all_facts_of ctxt =
339   maps Facts.selections
340    (Facts.dest_static [] (PureThy.facts_of (ProofContext.theory_of ctxt)) @
341     Facts.dest_static [] (ProofContext.facts_of ctxt));
343 val limit = ref 40;
345 fun find_theorems ctxt opt_goal rem_dups raw_criteria =
346   let
347     val add_prems = Seq.hd o (TRY (Method.insert_tac
348                                      (Assumption.prems_of ctxt) 1));
349     val opt_goal' = Option.map add_prems opt_goal;
351     val criteria = map (apsnd (read_criterion ctxt)) raw_criteria;
352     val filters = map (filter_criterion ctxt opt_goal') criteria;
354     val raw_matches = all_filters filters (all_facts_of ctxt);
356     val matches =
357       if rem_dups
358       then rem_thm_dups (nicer_shortest ctxt) raw_matches
359       else raw_matches;
360   in matches end;
362 fun print_theorems ctxt opt_goal opt_limit rem_dups raw_criteria =
363   let
364     val start = start_timing ();
366     val criteria = map (apsnd (read_criterion ctxt)) raw_criteria;
367     val matches = find_theorems ctxt opt_goal rem_dups raw_criteria;
369     val len = length matches;
370     val lim = the_default (! limit) opt_limit;
371     val thms = Library.drop (len - lim, matches);
373     val end_msg = " in " ^
374                   (List.nth (String.tokens Char.isSpace (end_timing start), 3))
375                   ^ " secs"
376   in
377     Pretty.big_list "searched for:" (map (pretty_criterion ctxt) criteria)
378         :: Pretty.str "" ::
379      (if null thms then [Pretty.str ("nothing found" ^ end_msg)]
380       else
381         [Pretty.str ("found " ^ string_of_int len ^ " theorems" ^
382           (if len <= lim then ""
383            else " (" ^ string_of_int lim ^ " displayed)")
384            ^ end_msg ^ ":"), Pretty.str ""] @
385         map Display.pretty_fact thms)
386     |> Pretty.chunks |> Pretty.writeln
387   end;
391 (** command syntax **)
393 fun find_theorems_cmd ((opt_lim, rem_dups), spec) =
394   Toplevel.unknown_theory o Toplevel.keep (fn state =>
395   let
396     val proof_state = Toplevel.enter_proof_body state;
397     val ctxt = Proof.context_of proof_state;
398     val opt_goal = try Proof.get_goal proof_state |> Option.map (#2 o #2);
399   in print_theorems ctxt opt_goal opt_lim rem_dups spec end);
401 local
403 structure P = OuterParse and K = OuterKeyword;
405 val criterion =
406   P.reserved "name" |-- P.!!! (P.\$\$\$ ":" |-- P.xname) >> Name ||
407   P.reserved "intro" >> K Intro ||
408   P.reserved "elim" >> K Elim ||
409   P.reserved "dest" >> K Dest ||
410   P.reserved "solves" >> K Solves ||
411   P.reserved "simp" |-- P.!!! (P.\$\$\$ ":" |-- P.term) >> Simp ||
412   P.term >> Pattern;
414 val options =
415   Scan.optional
416     (P.\$\$\$ "(" |--
417       P.!!! (Scan.option P.nat -- Scan.optional (P.reserved "with_dups" >> K false) true
418         --| P.\$\$\$ ")")) (NONE, true);
419 in
421 val _ =
422   OuterSyntax.improper_command "find_theorems" "print theorems meeting specified criteria" K.diag
423     (options -- Scan.repeat (((Scan.option P.minus >> is_none) -- criterion))
424       >> (Toplevel.no_timing oo find_theorems_cmd));
426 end;
428 end;