4 Goals in tactical theorem proving.
9 val parallel_proofs: int Unsynchronized.ref
10 val parallel_proofs_threshold: int Unsynchronized.ref
11 val SELECT_GOAL: tactic -> int -> tactic
12 val CONJUNCTS: tactic -> int -> tactic
13 val PRECISE_CONJUNCTS: int -> tactic -> int -> tactic
14 val PARALLEL_CHOICE: tactic list -> tactic
15 val PARALLEL_GOALS: tactic -> tactic
21 val init: cterm -> thm
22 val protect: thm -> thm
23 val conclude: thm -> thm
24 val check_finished: Proof.context -> thm -> unit
25 val finish: Proof.context -> thm -> thm
26 val norm_result: thm -> thm
27 val fork_name: string -> (unit -> 'a) -> 'a future
28 val fork: (unit -> 'a) -> 'a future
29 val future_enabled: unit -> bool
30 val local_future_enabled: unit -> bool
31 val future_result: Proof.context -> thm future -> term -> thm
32 val prove_internal: cterm list -> cterm -> (thm list -> tactic) -> thm
33 val prove_multi: Proof.context -> string list -> term list -> term list ->
34 ({prems: thm list, context: Proof.context} -> tactic) -> thm list
35 val prove_future: Proof.context -> string list -> term list -> term ->
36 ({prems: thm list, context: Proof.context} -> tactic) -> thm
37 val prove: Proof.context -> string list -> term list -> term ->
38 ({prems: thm list, context: Proof.context} -> tactic) -> thm
39 val prove_global: theory -> string list -> term list -> term ->
40 ({prems: thm list, context: Proof.context} -> tactic) -> thm
41 val extract: int -> int -> thm -> thm Seq.seq
42 val retrofit: int -> int -> thm -> thm -> thm Seq.seq
43 val conjunction_tac: int -> tactic
44 val precise_conjunction_tac: int -> int -> tactic
45 val recover_conjunction_tac: tactic
46 val norm_hhf_tac: int -> tactic
47 val compose_hhf_tac: thm -> int -> tactic
48 val assume_rule_tac: Proof.context -> int -> tactic
51 structure Goal: GOAL =
61 let val A = #1 (Thm.dest_implies (Thm.cprop_of Drule.protectI))
62 in fn C => Thm.instantiate ([], [(A, C)]) Drule.protectI end;
69 fun protect th = Drule.comp_no_flatten (th, 0) 1 Drule.protectI;
73 ---------------- (conclude)
76 fun conclude th = Drule.comp_no_flatten (th, Thm.nprems_of th) 1 Drule.protectD;
83 fun check_finished ctxt th =
84 (case Thm.nprems_of th of
86 | n => raise THM ("Proof failed.\n" ^
87 Pretty.string_of (Pretty.chunks
88 (Goal_Display.pretty_goals
90 |> Config.put Goal_Display.goals_limit n
91 |> Config.put Goal_Display.show_main_goal true) th)) ^
92 "\n" ^ string_of_int n ^ " unsolved goal(s)!", 0, [th]));
94 fun finish ctxt th = (check_finished ctxt th; conclude th);
103 Drule.flexflex_unique
104 #> Raw_Simplifier.norm_hhf_protect
106 #> Drule.zero_var_indexes;
111 val forked_proofs = Synchronized.var "forked_proofs" 0;
114 Synchronized.change forked_proofs (fn m =>
118 Multithreading.tracing 2 (fn () =>
119 ("PROOFS " ^ Time.toString (Time.now ()) ^ ": " ^ string_of_int n));
122 fun fork_name name e =
123 uninterruptible (fn _ => fn () =>
127 singleton (Future.forks {name = name, group = NONE, deps = [], pri = ~1})
131 (Exn.capture Future.status e before forked ~1
132 handle exn => (forked ~1; reraise exn)));
135 fun fork e = fork_name "Goal.fork" e;
138 (* scheduling parameters *)
140 val parallel_proofs = Unsynchronized.ref 1;
141 val parallel_proofs_threshold = Unsynchronized.ref 50;
143 fun future_enabled () =
144 Multithreading.enabled () andalso ! parallel_proofs >= 1 andalso
145 is_some (Future.worker_task ());
147 fun local_future_enabled () =
148 future_enabled () andalso ! parallel_proofs >= 2 andalso
149 Synchronized.value forked_proofs <
150 ! parallel_proofs_threshold * Multithreading.max_threads_value ();
155 fun future_result ctxt result prop =
157 val thy = Proof_Context.theory_of ctxt;
158 val _ = Context.reject_draft thy;
159 val cert = Thm.cterm_of thy;
160 val certT = Thm.ctyp_of thy;
162 val assms = Assumption.all_assms_of ctxt;
163 val As = map Thm.term_of assms;
165 val xs = map Free (fold Term.add_frees (prop :: As) []);
166 val fixes = map cert xs;
168 val tfrees = fold Term.add_tfrees (prop :: As) [];
169 val instT = map (fn (a, S) => (certT (TVar ((a, 0), S)), certT (TFree (a, S)))) tfrees;
172 cert (Term.map_types Logic.varifyT_global
173 (fold_rev Logic.all xs (Logic.list_implies (As, prop))))
174 |> Thm.weaken_sorts (Variable.sorts_of ctxt);
175 val global_result = result |> Future.map
176 (Drule.flexflex_unique #>
177 Thm.adjust_maxidx_thm ~1 #>
178 Drule.implies_intr_list assms #>
179 Drule.forall_intr_list fixes #>
180 Thm.generalize (map #1 tfrees, []) 0 #>
183 Thm.future global_result global_prop
184 |> Thm.instantiate (instT, [])
185 |> Drule.forall_elim_list fixes
186 |> fold (Thm.elim_implies o Thm.assume) assms;
191 (** tactical theorem proving **)
193 (* prove_internal -- minimal checks, no normalization of result! *)
195 fun prove_internal casms cprop tac =
196 (case SINGLE (tac (map Assumption.assume casms)) (init cprop) of
197 SOME th => Drule.implies_intr_list casms
198 (finish (Syntax.init_pretty_global (Thm.theory_of_thm th)) th)
199 | NONE => error "Tactic failed");
202 (* prove_common etc. *)
204 fun prove_common immediate ctxt xs asms props tac =
206 val thy = Proof_Context.theory_of ctxt;
207 val string_of_term = Syntax.string_of_term ctxt;
209 val pos = Position.thread_data ();
210 fun err msg = cat_error msg
211 ("The error(s) above occurred for the goal statement:\n" ^
212 string_of_term (Logic.list_implies (asms, Logic.mk_conjunction_list props)) ^
213 (case Position.str_of pos of "" => "" | s => "\n" ^ s));
215 fun cert_safe t = Thm.cterm_of thy (Envir.beta_norm (Term.no_dummy_patterns t))
216 handle TERM (msg, _) => err msg | TYPE (msg, _, _) => err msg;
217 val casms = map cert_safe asms;
218 val cprops = map cert_safe props;
220 val (prems, ctxt') = ctxt
221 |> Variable.add_fixes_direct xs
222 |> fold Variable.declare_term (asms @ props)
223 |> Assumption.add_assumes casms
224 ||> Variable.set_body true;
225 val sorts = Variable.sorts_of ctxt';
227 val stmt = Thm.weaken_sorts sorts (Conjunction.mk_conjunction_balanced cprops);
230 (case SINGLE (tac {prems = prems, context = ctxt'}) (init stmt) of
231 NONE => err "Tactic failed"
233 let val res = finish ctxt' st handle THM (msg, _, _) => err msg in
234 if Unify.matches_list thy [Thm.term_of stmt] [Thm.prop_of res]
235 then Thm.check_shyps sorts res
236 else err ("Proved a different theorem: " ^ string_of_term (Thm.prop_of res))
239 if immediate orelse #maxidx (Thm.rep_cterm stmt) >= 0 orelse not (future_enabled ())
241 else future_result ctxt' (fork result) (Thm.term_of stmt);
243 Conjunction.elim_balanced (length props) res
244 |> map (Assumption.export false ctxt' ctxt)
245 |> Variable.export ctxt' ctxt
246 |> map Drule.zero_var_indexes
249 val prove_multi = prove_common true;
251 fun prove_future ctxt xs asms prop tac = hd (prove_common false ctxt xs asms [prop] tac);
252 fun prove ctxt xs asms prop tac = hd (prove_common true ctxt xs asms [prop] tac);
254 fun prove_global thy xs asms prop tac =
255 Drule.export_without_context (prove (Proof_Context.init_global thy) xs asms prop tac);
259 (** goal structure **)
264 (if i < 1 orelse n < 1 orelse i + n - 1 > Thm.nprems_of st then Seq.empty
265 else if n = 1 then Seq.single (Thm.cprem_of st i)
267 Seq.single (Conjunction.mk_conjunction_balanced (map (Thm.cprem_of st) (i upto i + n - 1))))
268 |> Seq.map (Thm.adjust_maxidx_cterm ~1 #> init);
270 fun retrofit i n st' st =
272 else st |> Drule.with_subgoal i (Conjunction.uncurry_balanced n))
273 |> Thm.compose_no_flatten false (conclude st', Thm.nprems_of st') i;
275 fun SELECT_GOAL tac i st =
276 if Thm.nprems_of st = 1 andalso i = 1 then tac st
277 else Seq.lifts (retrofit i 1) (Seq.maps tac (extract i 1 st)) st;
282 fun precise_conjunction_tac 0 i = eq_assume_tac i
283 | precise_conjunction_tac 1 i = SUBGOAL (K all_tac) i
284 | precise_conjunction_tac n i = PRIMITIVE (Drule.with_subgoal i (Conjunction.curry_balanced n));
286 val adhoc_conjunction_tac = REPEAT_ALL_NEW
287 (SUBGOAL (fn (goal, i) =>
288 if can Logic.dest_conjunction goal then rtac Conjunction.conjunctionI i
291 val conjunction_tac = SUBGOAL (fn (goal, i) =>
292 precise_conjunction_tac (length (Logic.dest_conjunctions goal)) i ORELSE
293 TRY (adhoc_conjunction_tac i));
295 val recover_conjunction_tac = PRIMITIVE (fn th =>
296 Conjunction.uncurry_balanced (Thm.nprems_of th) th);
298 fun PRECISE_CONJUNCTS n tac =
299 SELECT_GOAL (precise_conjunction_tac n 1
301 THEN recover_conjunction_tac);
304 SELECT_GOAL (conjunction_tac 1
306 THEN recover_conjunction_tac);
309 (* hhf normal form *)
312 rtac Drule.asm_rl (*cheap approximation -- thanks to builtin Logic.flatten_params*)
313 THEN' SUBGOAL (fn (t, i) =>
314 if Drule.is_norm_hhf t then all_tac
315 else rewrite_goal_tac Drule.norm_hhf_eqs i);
317 fun compose_hhf_tac th i st =
318 PRIMSEQ (Thm.bicompose false (false, Drule.lift_all (Thm.cprem_of st i) th, 0) i) st;
321 (* non-atomic goal assumptions *)
323 fun non_atomic (Const ("==>", _) $ _ $ _) = true
324 | non_atomic (Const ("all", _) $ _) = true
325 | non_atomic _ = false;
327 fun assume_rule_tac ctxt = norm_hhf_tac THEN' CSUBGOAL (fn (goal, i) =>
329 val ((_, goal'), ctxt') = Variable.focus goal ctxt;
330 val goal'' = Drule.cterm_rule (singleton (Variable.export ctxt' ctxt)) goal';
331 val Rs = filter (non_atomic o Thm.term_of) (Drule.strip_imp_prems goal'');
332 val tacs = Rs |> map (fn R =>
333 Tactic.etac (Raw_Simplifier.norm_hhf (Thm.trivial R)) THEN_ALL_NEW assume_tac);
334 in fold_rev (curry op APPEND') tacs (K no_tac) i end);
337 (* parallel tacticals *)
339 (*parallel choice of single results*)
340 fun PARALLEL_CHOICE tacs st =
341 (case Par_List.get_some (fn tac => SINGLE tac st) tacs of
343 | SOME st' => Seq.single st');
345 (*parallel refinement of non-schematic goal by single results*)
346 exception FAILED of unit;
347 fun PARALLEL_GOALS tac =
348 Thm.adjust_maxidx_thm ~1 #>
350 if not (future_enabled ()) orelse Thm.maxidx_of st >= 0 orelse Thm.nprems_of st <= 1
355 (case SINGLE tac g of
356 NONE => raise FAILED ()
359 val goals = Drule.strip_imp_prems (Thm.cprop_of st);
360 val results = Par_List.map (try_tac o init) goals;
361 in ALLGOALS (fn i => retrofit i 1 (nth results (i - 1))) st end
362 handle FAILED () => Seq.empty);
366 structure Basic_Goal: BASIC_GOAL = Goal;