--- a/src/Sequents/prover.ML Tue Jul 27 19:00:55 1999 +0200
+++ b/src/Sequents/prover.ML Tue Jul 27 19:01:46 1999 +0200
@@ -2,12 +2,14 @@
ID: $Id$
Author: Lawrence C Paulson, Cambridge University Computer Laboratory
Copyright 1992 University of Cambridge
+
+Simple classical reasoner for the sequent calculus, based on "theorem packs"
*)
-(**** Theorem Packs ****)
-(* based largely on LK *)
+(*Higher precedence than := facilitates use of references*)
+infix 4 add_safes add_unsafes;
datatype pack = Pack of thm list * thm list;
@@ -19,17 +21,37 @@
val empty_pack = Pack([],[]);
-infix 4 add_safes add_unsafes;
+fun warn_duplicates [] = []
+ | warn_duplicates dups =
+ (warning (String.concat ("Ignoring duplicate theorems:\n"::
+ map (suffix "\n" o string_of_thm) dups));
+ dups);
fun (Pack(safes,unsafes)) add_safes ths =
- Pack(sort (make_ord less) (ths@safes), unsafes);
+ let val dups = warn_duplicates (gen_inter eq_thm (ths,safes))
+ val ths' = gen_rems eq_thm (ths,dups)
+ in
+ Pack(sort (make_ord less) (ths'@safes), unsafes)
+ end;
fun (Pack(safes,unsafes)) add_unsafes ths =
- Pack(safes, sort (make_ord less) (ths@unsafes));
+ let val dups = warn_duplicates (gen_inter eq_thm (ths,unsafes))
+ val ths' = gen_rems eq_thm (ths,dups)
+ in
+ Pack(safes, sort (make_ord less) (ths'@unsafes))
+ end;
+
+fun merge_pack (Pack(safes,unsafes), Pack(safes',unsafes')) =
+ Pack(sort (make_ord less) (safes@safes'),
+ sort (make_ord less) (unsafes@unsafes'));
+fun print_pack (Pack(safes,unsafes)) =
+ (writeln "Safe rules:"; print_thms safes;
+ writeln "Unsafe rules:"; print_thms unsafes);
+
(*Returns the list of all formulas in the sequent*)
-fun forms_of_seq (Const("Sequents.SeqO'",_) $ P $ u) = P :: forms_of_seq u
+fun forms_of_seq (Const("SeqO'",_) $ P $ u) = P :: forms_of_seq u
| forms_of_seq (H $ u) = forms_of_seq u
| forms_of_seq _ = [];
@@ -112,11 +134,13 @@
(*Tries safe rules only*)
-fun safe_goal_tac (Pack(safes,unsafes)) = reresolve_tac safes;
+fun safe_tac (Pack(safes,unsafes)) = reresolve_tac safes;
+
+val safe_goal_tac = safe_tac; (*backwards compatibility*)
(*Tries a safe rule or else a unsafe rule. Single-step for tracing. *)
fun step_tac (thm_pack as Pack(safes,unsafes)) =
- safe_goal_tac thm_pack ORELSE'
+ safe_tac thm_pack ORELSE'
filseq_resolve_tac unsafes 9999;
@@ -138,87 +162,38 @@
-signature MODAL_PROVER_RULE =
-sig
- val rewrite_rls : thm list
- val safe_rls : thm list
- val unsafe_rls : thm list
- val bound_rls : thm list
- val aside_rls : thm list
-end;
-
-signature MODAL_PROVER =
-sig
- val rule_tac : thm list -> int ->tactic
- val step_tac : int -> tactic
- val solven_tac : int -> int -> tactic
- val solve_tac : int -> tactic
-end;
+structure ProverArgs =
+ struct
+ val name = "Sequents/prover";
+ type T = pack ref;
+ val empty = ref empty_pack
+ fun copy (ref pack) = ref pack;
+ val prep_ext = copy;
+ fun merge (ref pack1, ref pack2) = ref (merge_pack (pack1, pack2));
+ fun print _ (ref pack) = print_pack pack;
+ end;
-functor Modal_ProverFun (Modal_Rule: MODAL_PROVER_RULE) : MODAL_PROVER =
-struct
-local open Modal_Rule
-in
+structure ProverData = TheoryDataFun(ProverArgs);
-(*Returns the list of all formulas in the sequent*)
-fun forms_of_seq (Const("Sequents.SeqO",_) $ P $ u) = P :: forms_of_seq u
- | forms_of_seq (H $ u) = forms_of_seq u
- | forms_of_seq _ = [];
-
-(*Tests whether two sequences (left or right sides) could be resolved.
- seqp is a premise (subgoal), seqc is a conclusion of an object-rule.
- Assumes each formula in seqc is surrounded by sequence variables
- -- checks that each concl formula looks like some subgoal formula.*)
-fun could_res (seqp,seqc) =
- forall (fn Qc => exists (fn Qp => could_unify (Qp,Qc))
- (forms_of_seq seqp))
- (forms_of_seq seqc);
+val prover_setup = [ProverData.init];
-(*Tests whether two sequents G|-H could be resolved, comparing each side.*)
-fun could_resolve_seq (prem,conc) =
- case (prem,conc) of
- (_ $ Abs(_,_,leftp) $ Abs(_,_,rightp),
- _ $ Abs(_,_,leftc) $ Abs(_,_,rightc)) =>
- could_res (leftp,leftc) andalso could_res (rightp,rightc)
- | _ => false;
+val print_thm_pack = ProverData.print;
+val thm_pack_ref_of_sg = ProverData.get_sg;
+val thm_pack_ref_of = ProverData.get;
-(*Like filt_resolve_tac, using could_resolve_seq
- Much faster than resolve_tac when there are many rules.
- Resolve subgoal i using the rules, unless more than maxr are compatible. *)
-fun filseq_resolve_tac rules maxr = SUBGOAL(fn (prem,i) =>
- let val rls = filter_thms could_resolve_seq (maxr+1, prem, rules)
- in if length rls > maxr then no_tac else resolve_tac rls i
- end);
+(* access global thm_pack *)
-fun fresolve_tac rls n = filseq_resolve_tac rls 999 n;
-
-(* NB No back tracking possible with aside rules *)
-
-fun aside_tac n = DETERM(REPEAT (filt_resolve_tac aside_rls 999 n));
-fun rule_tac rls n = fresolve_tac rls n THEN aside_tac n;
+val thm_pack_of_sg = ! o thm_pack_ref_of_sg;
+val thm_pack_of = thm_pack_of_sg o sign_of;
-val fres_safe_tac = fresolve_tac safe_rls;
-val fres_unsafe_tac = fresolve_tac unsafe_rls THEN' aside_tac;
-val fres_bound_tac = fresolve_tac bound_rls;
+val thm_pack = thm_pack_of o Context.the_context;
+val thm_pack_ref = thm_pack_ref_of_sg o sign_of o Context.the_context;
-fun UPTOGOAL n tf = let fun tac i = if i<n then all_tac
- else tf(i) THEN tac(i-1)
- in fn st => tac (nprems_of st) st end;
+
+(* change global thm_pack *)
-(* Depth first search bounded by d *)
-fun solven_tac d n state = state |>
- (if d<0 then no_tac
- else if (nprems_of state = 0) then all_tac
- else (DETERM(fres_safe_tac n) THEN UPTOGOAL n (solven_tac d)) ORELSE
- ((fres_unsafe_tac n THEN UPTOGOAL n (solven_tac d)) APPEND
- (fres_bound_tac n THEN UPTOGOAL n (solven_tac (d-1)))));
+fun change_thm_pack f x = thm_pack_ref () := (f (thm_pack (), x));
-fun solve_tac d = rewrite_goals_tac rewrite_rls THEN solven_tac d 1;
+val Add_safes = change_thm_pack (op add_safes);
+val Add_unsafes = change_thm_pack (op add_unsafes);
-fun step_tac n =
- COND (has_fewer_prems 1) all_tac
- (DETERM(fres_safe_tac n) ORELSE
- (fres_unsafe_tac n APPEND fres_bound_tac n));
-
-end;
-end;