src/HOL/Tools/meson.ML
author wenzelm
Sat, 21 Jul 2007 23:25:00 +0200
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tactics: avoid dynamic reference to accidental theory context (via ML_Context.the_context etc.);
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(*  Title:      HOL/Tools/meson.ML
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    ID:         $Id$
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    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
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    Copyright   1992  University of Cambridge
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The MESON resolution proof procedure for HOL.
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When making clauses, avoids using the rewriter -- instead uses RS recursively
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NEED TO SORT LITERALS BY # OF VARS, USING ==>I/E.  ELIMINATES NEED FOR
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FUNCTION nodups -- if done to goal clauses too!
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*)
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signature BASIC_MESON =
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sig
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  val size_of_subgoals	: thm -> int
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  val make_cnf		: thm list -> thm -> thm list
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  val finish_cnf	: thm list -> thm list
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  val make_nnf		: thm -> thm
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  val make_nnf1		: thm -> thm
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  val skolemize		: thm -> thm
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  val make_clauses	: thm list -> thm list
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  val make_horns	: thm list -> thm list
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  val best_prolog_tac	: (thm -> int) -> thm list -> tactic
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  val depth_prolog_tac	: thm list -> tactic
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  val gocls		: thm list -> thm list
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  val skolemize_prems_tac	: thm list -> int -> tactic
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  val MESON		: (thm list -> thm list) -> (thm list -> tactic) -> int -> tactic
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  val best_meson_tac	: (thm -> int) -> int -> tactic
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  val safe_best_meson_tac	: int -> tactic
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  val depth_meson_tac	: int -> tactic
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  val prolog_step_tac'	: thm list -> int -> tactic
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  val iter_deepen_prolog_tac	: thm list -> tactic
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  val iter_deepen_meson_tac	: thm list -> int -> tactic
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  val meson_tac		: int -> tactic
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  val negate_head	: thm -> thm
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  val select_literal	: int -> thm -> thm
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  val skolemize_tac	: int -> tactic
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end
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structure Meson =
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struct
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val not_conjD = thm "meson_not_conjD";
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val not_disjD = thm "meson_not_disjD";
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val not_notD = thm "meson_not_notD";
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val not_allD = thm "meson_not_allD";
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val not_exD = thm "meson_not_exD";
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val imp_to_disjD = thm "meson_imp_to_disjD";
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val not_impD = thm "meson_not_impD";
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val iff_to_disjD = thm "meson_iff_to_disjD";
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val not_iffD = thm "meson_not_iffD";
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val conj_exD1 = thm "meson_conj_exD1";
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val conj_exD2 = thm "meson_conj_exD2";
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val disj_exD = thm "meson_disj_exD";
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val disj_exD1 = thm "meson_disj_exD1";
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val disj_exD2 = thm "meson_disj_exD2";
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val disj_assoc = thm "meson_disj_assoc";
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val disj_comm = thm "meson_disj_comm";
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val disj_FalseD1 = thm "meson_disj_FalseD1";
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val disj_FalseD2 = thm "meson_disj_FalseD2";
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val depth_limit = ref 2000;
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(**** Operators for forward proof ****)
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(** First-order Resolution **)
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fun typ_pair_of (ix, (sort,ty)) = (TVar (ix,sort), ty);
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fun term_pair_of (ix, (ty,t)) = (Var (ix,ty), t);
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val Envir.Envir {asol = tenv0, iTs = tyenv0, ...} = Envir.empty 0
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(*FIXME: currently does not "rename variables apart"*)
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fun first_order_resolve thA thB =
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  let val thy = theory_of_thm thA
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      val tmA = concl_of thA
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      val Const("==>",_) $ tmB $ _ = prop_of thB
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      val (tyenv,tenv) = Pattern.first_order_match thy (tmB,tmA) (tyenv0,tenv0)
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      val ct_pairs = map (pairself (cterm_of thy) o term_pair_of) (Vartab.dest tenv)
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  in  thA RS (cterm_instantiate ct_pairs thB)  end
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  handle _ => raise THM ("first_order_resolve", 0, [thA,thB]);
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fun flexflex_first_order th = 
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  case (tpairs_of th) of
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      [] => th
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    | pairs =>
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	let val thy = theory_of_thm th
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	    val (tyenv,tenv) = 
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	          foldl (uncurry (Pattern.first_order_match thy)) (tyenv0,tenv0) pairs
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	    val t_pairs = map term_pair_of (Vartab.dest tenv)
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	    val th' = Thm.instantiate ([], map (pairself (cterm_of thy)) t_pairs) th
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	in  th'  end
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	handle THM _ => th;
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(*raises exception if no rules apply -- unlike RL*)
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fun tryres (th, rls) = 
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  let fun tryall [] = raise THM("tryres", 0, th::rls)
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        | tryall (rl::rls) = (th RS rl handle THM _ => tryall rls)
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  in  tryall rls  end;
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(*Permits forward proof from rules that discharge assumptions. The supplied proof state st,
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  e.g. from conj_forward, should have the form
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    "[| P' ==> ?P; Q' ==> ?Q |] ==> ?P & ?Q"
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  and the effect should be to instantiate ?P and ?Q with normalized versions of P' and Q'.*)
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fun forward_res nf st =
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  let fun forward_tacf [prem] = rtac (nf prem) 1
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        | forward_tacf prems = 
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            error ("Bad proof state in forward_res, please inform lcp@cl.cam.ac.uk:\n" ^
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                   string_of_thm st ^
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                   "\nPremises:\n" ^
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                   cat_lines (map string_of_thm prems))
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  in
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    case Seq.pull (ALLGOALS (METAHYPS forward_tacf) st)
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    of SOME(th,_) => th
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     | NONE => raise THM("forward_res", 0, [st])
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  end;
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(*Are any of the logical connectives in "bs" present in the term?*)
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fun has_conns bs =
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  let fun has (Const(a,_)) = false
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        | has (Const("Trueprop",_) $ p) = has p
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        | has (Const("Not",_) $ p) = has p
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        | has (Const("op |",_) $ p $ q) = member (op =) bs "op |" orelse has p orelse has q
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        | has (Const("op &",_) $ p $ q) = member (op =) bs "op &" orelse has p orelse has q
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        | has (Const("All",_) $ Abs(_,_,p)) = member (op =) bs "All" orelse has p
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        | has (Const("Ex",_) $ Abs(_,_,p)) = member (op =) bs "Ex" orelse has p
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	| has _ = false
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  in  has  end;
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(**** Clause handling ****)
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fun literals (Const("Trueprop",_) $ P) = literals P
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  | literals (Const("op |",_) $ P $ Q) = literals P @ literals Q
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  | literals (Const("Not",_) $ P) = [(false,P)]
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  | literals P = [(true,P)];
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(*number of literals in a term*)
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val nliterals = length o literals;
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(*** Tautology Checking ***)
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fun signed_lits_aux (Const ("op |", _) $ P $ Q) (poslits, neglits) = 
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      signed_lits_aux Q (signed_lits_aux P (poslits, neglits))
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  | signed_lits_aux (Const("Not",_) $ P) (poslits, neglits) = (poslits, P::neglits)
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  | signed_lits_aux P (poslits, neglits) = (P::poslits, neglits);
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fun signed_lits th = signed_lits_aux (HOLogic.dest_Trueprop (concl_of th)) ([],[]);
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(*Literals like X=X are tautologous*)
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fun taut_poslit (Const("op =",_) $ t $ u) = t aconv u
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  | taut_poslit (Const("True",_)) = true
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  | taut_poslit _ = false;
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fun is_taut th =
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  let val (poslits,neglits) = signed_lits th
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  in  exists taut_poslit poslits
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      orelse
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      exists (member (op aconv) neglits) (HOLogic.false_const :: poslits)
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  end
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  handle TERM _ => false;	(*probably dest_Trueprop on a weird theorem*)		      
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(*** To remove trivial negated equality literals from clauses ***)
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(*They are typically functional reflexivity axioms and are the converses of
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  injectivity equivalences*)
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val not_refl_disj_D = thm"meson_not_refl_disj_D";
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(*Is either term a Var that does not properly occur in the other term?*)
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fun eliminable (t as Var _, u) = t aconv u orelse not (Logic.occs(t,u))
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  | eliminable (u, t as Var _) = t aconv u orelse not (Logic.occs(t,u))
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  | eliminable _ = false;
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fun refl_clause_aux 0 th = th
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  | refl_clause_aux n th =
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       case HOLogic.dest_Trueprop (concl_of th) of
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	  (Const ("op |", _) $ (Const ("op |", _) $ _ $ _) $ _) => 
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            refl_clause_aux n (th RS disj_assoc)    (*isolate an atom as first disjunct*)
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	| (Const ("op |", _) $ (Const("Not",_) $ (Const("op =",_) $ t $ u)) $ _) => 
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	    if eliminable(t,u) 
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	    then refl_clause_aux (n-1) (th RS not_refl_disj_D)  (*Var inequation: delete*)
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	    else refl_clause_aux (n-1) (th RS disj_comm)  (*not between Vars: ignore*)
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	| (Const ("op |", _) $ _ $ _) => refl_clause_aux n (th RS disj_comm)
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	| _ => (*not a disjunction*) th;
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fun notequal_lits_count (Const ("op |", _) $ P $ Q) = 
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      notequal_lits_count P + notequal_lits_count Q
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  | notequal_lits_count (Const("Not",_) $ (Const("op =",_) $ _ $ _)) = 1
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  | notequal_lits_count _ = 0;
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(*Simplify a clause by applying reflexivity to its negated equality literals*)
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fun refl_clause th = 
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  let val neqs = notequal_lits_count (HOLogic.dest_Trueprop (concl_of th))
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  in  zero_var_indexes (refl_clause_aux neqs th)  end
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  handle TERM _ => th;	(*probably dest_Trueprop on a weird theorem*)		      
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(*** The basic CNF transformation ***)
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val max_clauses = ref 40;
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fun sum x y = if x < !max_clauses andalso y < !max_clauses then x+y else !max_clauses;
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fun prod x y = if x < !max_clauses andalso y < !max_clauses then x*y else !max_clauses;
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(*Estimate the number of clauses in order to detect infeasible theorems*)
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fun signed_nclauses b (Const("Trueprop",_) $ t) = signed_nclauses b t
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  | signed_nclauses b (Const("Not",_) $ t) = signed_nclauses (not b) t
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  | signed_nclauses b (Const("op &",_) $ t $ u) = 
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      if b then sum (signed_nclauses b t) (signed_nclauses b u)
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           else prod (signed_nclauses b t) (signed_nclauses b u)
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  | signed_nclauses b (Const("op |",_) $ t $ u) = 
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      if b then prod (signed_nclauses b t) (signed_nclauses b u)
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           else sum (signed_nclauses b t) (signed_nclauses b u)
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  | signed_nclauses b (Const("op -->",_) $ t $ u) = 
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      if b then prod (signed_nclauses (not b) t) (signed_nclauses b u)
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           else sum (signed_nclauses (not b) t) (signed_nclauses b u)
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  | signed_nclauses b (Const("op =", Type ("fun", [T, _])) $ t $ u) = 
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      if T = HOLogic.boolT then (*Boolean equality is if-and-only-if*)
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	  if b then sum (prod (signed_nclauses (not b) t) (signed_nclauses b u))
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			(prod (signed_nclauses (not b) u) (signed_nclauses b t))
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	       else sum (prod (signed_nclauses b t) (signed_nclauses b u))
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			(prod (signed_nclauses (not b) t) (signed_nclauses (not b) u))
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      else 1 
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  | signed_nclauses b (Const("Ex", _) $ Abs (_,_,t)) = signed_nclauses b t
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  | signed_nclauses b (Const("All",_) $ Abs (_,_,t)) = signed_nclauses b t
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  | signed_nclauses _ _ = 1; (* literal *)
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val nclauses = signed_nclauses true;
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fun too_many_clauses t = nclauses t >= !max_clauses;
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(*Replaces universally quantified variables by FREE variables -- because
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  assumptions may not contain scheme variables.  Later, we call "generalize". *)
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fun freeze_spec th =
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  let val newname = gensym "mes_"
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      val spec' = read_instantiate [("x", newname)] spec
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  in  th RS spec'  end;
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(*Used with METAHYPS below. There is one assumption, which gets bound to prem
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  and then normalized via function nf. The normal form is given to resolve_tac,
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  instantiate a Boolean variable created by resolution with disj_forward. Since
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  (nf prem) returns a LIST of theorems, we can backtrack to get all combinations.*)
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fun resop nf [prem] = resolve_tac (nf prem) 1;
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(*Any need to extend this list with 
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  "HOL.type_class","HOL.eq_class","ProtoPure.term"?*)
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val has_meta_conn = 
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    exists_Const (member (op =) ["==", "==>", "all", "prop"] o #1);
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fun apply_skolem_ths (th, rls) = 
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  let fun tryall [] = raise THM("apply_skolem_ths", 0, th::rls)
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        | tryall (rl::rls) = (first_order_resolve th rl handle THM _ => tryall rls)
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  in  tryall rls  end;
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(*Conjunctive normal form, adding clauses from th in front of ths (for foldr).
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  Strips universal quantifiers and breaks up conjunctions.
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  Eliminates existential quantifiers using skoths: Skolemization theorems.*)
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fun cnf skoths (th,ths) =
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  let fun cnf_aux (th,ths) =
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  	if not (can HOLogic.dest_Trueprop (prop_of th)) then ths (*meta-level: ignore*)
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        else if not (has_conns ["All","Ex","op &"] (prop_of th))  
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	then th::ths (*no work to do, terminate*)
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	else case head_of (HOLogic.dest_Trueprop (concl_of th)) of
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	    Const ("op &", _) => (*conjunction*)
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		cnf_aux (th RS conjunct1, cnf_aux (th RS conjunct2, ths))
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	  | Const ("All", _) => (*universal quantifier*)
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	        cnf_aux (freeze_spec th, ths)
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	  | Const ("Ex", _) => 
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	      (*existential quantifier: Insert Skolem functions*)
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	      cnf_aux (apply_skolem_ths (th,skoths), ths)
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	  | Const ("op |", _) => 
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	      (*Disjunction of P, Q: Create new goal of proving ?P | ?Q and solve it using
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	        all combinations of converting P, Q to CNF.*)
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	      let val tac =
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		  (METAHYPS (resop cnf_nil) 1) THEN
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		   (fn st' => st' |> METAHYPS (resop cnf_nil) 1)
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	      in  Seq.list_of (tac (th RS disj_forward)) @ ths  end 
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	  | _ => (*no work to do*) th::ths 
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      and cnf_nil th = cnf_aux (th,[])
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  in 
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    if too_many_clauses (concl_of th) 
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    then (Output.debug (fn () => ("cnf is ignoring: " ^ string_of_thm th)); ths)
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    else cnf_aux (th,ths)
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  end;
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fun all_names (Const ("all", _) $ Abs(x,_,P)) = x :: all_names P
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  | all_names _ = [];
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fun new_names n [] = []
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  | new_names n (x::xs) = 
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      if String.isPrefix "mes_" x then (x, radixstring(26,"A",n)) :: new_names (n+1) xs
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      else new_names n xs;
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(*The gensym names are ugly, so don't let the user see them. When forall_elim_vars
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  is called, it will ensure that no name clauses ensue.*)
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fun nice_names th =
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  let val old_names = all_names (prop_of th)
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  in  Drule.rename_bvars (new_names 0 old_names) th  end;
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(*Convert all suitable free variables to schematic variables, 
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  but don't discharge assumptions.*)
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fun generalize th = Thm.varifyT (forall_elim_vars 0 (nice_names (forall_intr_frees th)));
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fun make_cnf skoths th = cnf skoths (th, []);
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(*Generalization, removal of redundant equalities, removal of tautologies.*)
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fun finish_cnf ths = filter (not o is_taut) (map (refl_clause o generalize) ths);
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(**** Removal of duplicate literals ****)
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(*Forward proof, passing extra assumptions as theorems to the tactic*)
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fun forward_res2 nf hyps st =
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  case Seq.pull
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	(REPEAT
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	 (METAHYPS (fn major::minors => rtac (nf (minors@hyps) major) 1) 1)
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	 st)
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  of SOME(th,_) => th
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   | NONE => raise THM("forward_res2", 0, [st]);
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(*Remove duplicates in P|Q by assuming ~P in Q
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  rls (initially []) accumulates assumptions of the form P==>False*)
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fun nodups_aux rls th = nodups_aux rls (th RS disj_assoc)
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    handle THM _ => tryres(th,rls)
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    handle THM _ => tryres(forward_res2 nodups_aux rls (th RS disj_forward2),
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			   [disj_FalseD1, disj_FalseD2, asm_rl])
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    handle THM _ => th;
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(*Remove duplicate literals, if there are any*)
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fun nodups th =
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  if has_duplicates (op =) (literals (prop_of th))
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    then nodups_aux [] th
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    else th;
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(**** Generation of contrapositives ****)
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fun is_left (Const ("Trueprop", _) $ 
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               (Const ("op |", _) $ (Const ("op |", _) $ _ $ _) $ _)) = true
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  | is_left _ = false;
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(*Associate disjuctions to right -- make leftmost disjunct a LITERAL*)
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fun assoc_right th = 
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  if is_left (prop_of th) then assoc_right (th RS disj_assoc)
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  else th;
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(*Must check for negative literal first!*)
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val clause_rules = [disj_assoc, make_neg_rule, make_pos_rule];
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(*For ordinary resolution. *)
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val resolution_clause_rules = [disj_assoc, make_neg_rule', make_pos_rule'];
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(*Create a goal or support clause, conclusing False*)
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fun make_goal th =   (*Must check for negative literal first!*)
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    make_goal (tryres(th, clause_rules))
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  handle THM _ => tryres(th, [make_neg_goal, make_pos_goal]);
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(*Sort clauses by number of literals*)
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fun fewerlits(th1,th2) = nliterals(prop_of th1) < nliterals(prop_of th2);
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fun sort_clauses ths = sort (make_ord fewerlits) ths;
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(*True if the given type contains bool anywhere*)
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fun has_bool (Type("bool",_)) = true
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  | has_bool (Type(_, Ts)) = exists has_bool Ts
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  | has_bool _ = false;
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(*Is the string the name of a connective? Really only | and Not can remain, 
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  since this code expects to be called on a clause form.*)  
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val is_conn = member (op =)
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    ["Trueprop", "op &", "op |", "op -->", "Not", 
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     "All", "Ex", "Ball", "Bex"];
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(*True if the term contains a function--not a logical connective--where the type 
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  of any argument contains bool.*)
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val has_bool_arg_const = 
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    exists_Const
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      (fn (c,T) => not(is_conn c) andalso exists (has_bool) (binder_types T));
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(*A higher-order instance of a first-order constant? Example is the definition of 
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  HOL.one, 1, at a function type in theory SetsAndFunctions.*)
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fun higher_inst_const thy (c,T) = 
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  case binder_types T of
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      [] => false (*not a function type, OK*)
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    | Ts => length (binder_types (Sign.the_const_type thy c)) <> length Ts;
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(*Raises an exception if any Vars in the theorem mention type bool. 
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  Also rejects functions whose arguments are Booleans or other functions.*)
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fun is_fol_term thy t =
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    Term.is_first_order ["all","All","Ex"] t andalso
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    not (exists (has_bool o fastype_of) (term_vars t)  orelse
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	 has_bool_arg_const t  orelse  
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	 exists_Const (higher_inst_const thy) t orelse
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	 has_meta_conn t);
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parents: 19154
diff changeset
   401
21102
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   402
fun rigid t = not (is_Var (head_of t));
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   403
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   404
fun ok4horn (Const ("Trueprop",_) $ (Const ("op |", _) $ t $ _)) = rigid t
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   405
  | ok4horn (Const ("Trueprop",_) $ t) = rigid t
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   406
  | ok4horn _ = false;
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   407
15579
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   408
(*Create a meta-level Horn clause*)
21102
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   409
fun make_horn crules th = 
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   410
  if ok4horn (concl_of th) 
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   411
  then make_horn crules (tryres(th,crules)) handle THM _ => th
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   412
  else th;
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   413
16563
a92f96951355 meson method taking an argument list
paulson
parents: 16173
diff changeset
   414
(*Generate Horn clauses for all contrapositives of a clause. The input, th,
a92f96951355 meson method taking an argument list
paulson
parents: 16173
diff changeset
   415
  is a HOL disjunction.*)
15579
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   416
fun add_contras crules (th,hcs) =
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   417
  let fun rots (0,th) = hcs
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   418
	| rots (k,th) = zero_var_indexes (make_horn crules th) ::
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   419
			rots(k-1, assoc_right (th RS disj_comm))
15862
67574c1b15a0 removed unnecessary (?) check
paulson
parents: 15779
diff changeset
   420
  in case nliterals(prop_of th) of
15579
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   421
	1 => th::hcs
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   422
      | n => rots(n, assoc_right th)
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   423
  end;
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   424
15579
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   425
(*Use "theorem naming" to label the clauses*)
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   426
fun name_thms label =
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   427
    let fun name1 (th, (k,ths)) =
21646
c07b5b0e8492 thm/prf: separate official name vs. additional tags;
wenzelm
parents: 21616
diff changeset
   428
	  (k-1, PureThy.put_name_hint (label ^ string_of_int k) th :: ths)
15579
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   429
    in  fn ths => #2 (foldr name1 (length ths, []) ths)  end;
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   430
16563
a92f96951355 meson method taking an argument list
paulson
parents: 16173
diff changeset
   431
(*Is the given disjunction an all-negative support clause?*)
15579
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   432
fun is_negative th = forall (not o #1) (literals (prop_of th));
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   433
15579
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   434
val neg_clauses = List.filter is_negative;
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   435
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   436
15579
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   437
(***** MESON PROOF PROCEDURE *****)
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   438
15579
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   439
fun rhyps (Const("==>",_) $ (Const("Trueprop",_) $ A) $ phi,
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   440
	   As) = rhyps(phi, A::As)
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   441
  | rhyps (_, As) = As;
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   442
15579
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   443
(** Detecting repeated assumptions in a subgoal **)
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   444
15579
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   445
(*The stringtree detects repeated assumptions.*)
16801
4bb13fa6ae72 tuned concat_with_and;
wenzelm
parents: 16588
diff changeset
   446
fun ins_term (net,t) = Net.insert_term (op aconv) (t,t) net;
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   447
15579
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   448
(*detects repetitions in a list of terms*)
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   449
fun has_reps [] = false
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   450
  | has_reps [_] = false
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   451
  | has_reps [t,u] = (t aconv u)
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   452
  | has_reps ts = (Library.foldl ins_term (Net.empty, ts);  false)
19875
7405ce9d4f25 avoid unqualified exception names;
wenzelm
parents: 19728
diff changeset
   453
		  handle Net.INSERT => true;
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   454
15579
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   455
(*Like TRYALL eq_assume_tac, but avoids expensive THEN calls*)
18508
paulson
parents: 18405
diff changeset
   456
fun TRYING_eq_assume_tac 0 st = Seq.single st
paulson
parents: 18405
diff changeset
   457
  | TRYING_eq_assume_tac i st =
paulson
parents: 18405
diff changeset
   458
       TRYING_eq_assume_tac (i-1) (eq_assumption i st)
paulson
parents: 18405
diff changeset
   459
       handle THM _ => TRYING_eq_assume_tac (i-1) st;
paulson
parents: 18405
diff changeset
   460
paulson
parents: 18405
diff changeset
   461
fun TRYALL_eq_assume_tac st = TRYING_eq_assume_tac (nprems_of st) st;
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   462
15579
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   463
(*Loop checking: FAIL if trying to prove the same thing twice
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   464
  -- if *ANY* subgoal has repeated literals*)
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   465
fun check_tac st =
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   466
  if exists (fn prem => has_reps (rhyps(prem,[]))) (prems_of st)
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   467
  then  Seq.empty  else  Seq.single st;
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   468
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   469
15579
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   470
(* net_resolve_tac actually made it slower... *)
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   471
fun prolog_step_tac horns i =
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   472
    (assume_tac i APPEND resolve_tac horns i) THEN check_tac THEN
18508
paulson
parents: 18405
diff changeset
   473
    TRYALL_eq_assume_tac;
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   474
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   475
(*Sums the sizes of the subgoals, ignoring hypotheses (ancestors)*)
15579
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   476
fun addconcl(prem,sz) = size_of_term(Logic.strip_assums_concl prem) + sz
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   477
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   478
fun size_of_subgoals st = foldr addconcl 0 (prems_of st);
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   479
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   480
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   481
(*Negation Normal Form*)
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   482
val nnf_rls = [imp_to_disjD, iff_to_disjD, not_conjD, not_disjD,
9869
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   483
               not_impD, not_iffD, not_allD, not_exD, not_notD];
15581
f07e865d9d40 now checks for higher-order vars
paulson
parents: 15579
diff changeset
   484
21102
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   485
fun ok4nnf (Const ("Trueprop",_) $ (Const ("Not", _) $ t)) = rigid t
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   486
  | ok4nnf (Const ("Trueprop",_) $ t) = rigid t
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   487
  | ok4nnf _ = false;
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   488
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   489
fun make_nnf1 th = 
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   490
  if ok4nnf (concl_of th) 
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   491
  then make_nnf1 (tryres(th, nnf_rls))
9869
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   492
    handle THM _ =>
15581
f07e865d9d40 now checks for higher-order vars
paulson
parents: 15579
diff changeset
   493
        forward_res make_nnf1
9869
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   494
           (tryres(th, [conj_forward,disj_forward,all_forward,ex_forward]))
21102
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   495
    handle THM _ => th
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   496
  else th;
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   497
20018
5419a71d0baa removed the "tagging" feature
paulson
parents: 19894
diff changeset
   498
(*The simplification removes defined quantifiers and occurrences of True and False. 
5419a71d0baa removed the "tagging" feature
paulson
parents: 19894
diff changeset
   499
  nnf_ss also includes the one-point simprocs,
18405
afb1a52a7011 removal of some redundancies (e.g. one-point-rules) in clause production
paulson
parents: 18389
diff changeset
   500
  which are needed to avoid the various one-point theorems from generating junk clauses.*)
19894
7c7e15b27145 the "all_theorems" option and some fixes
paulson
parents: 19875
diff changeset
   501
val nnf_simps =
20018
5419a71d0baa removed the "tagging" feature
paulson
parents: 19894
diff changeset
   502
     [simp_implies_def, Ex1_def, Ball_def, Bex_def, if_True, 
19894
7c7e15b27145 the "all_theorems" option and some fixes
paulson
parents: 19875
diff changeset
   503
      if_False, if_cancel, if_eq_cancel, cases_simp];
7c7e15b27145 the "all_theorems" option and some fixes
paulson
parents: 19875
diff changeset
   504
val nnf_extra_simps =
7c7e15b27145 the "all_theorems" option and some fixes
paulson
parents: 19875
diff changeset
   505
      thms"split_ifs" @ ex_simps @ all_simps @ simp_thms;
18405
afb1a52a7011 removal of some redundancies (e.g. one-point-rules) in clause production
paulson
parents: 18389
diff changeset
   506
afb1a52a7011 removal of some redundancies (e.g. one-point-rules) in clause production
paulson
parents: 18389
diff changeset
   507
val nnf_ss =
19894
7c7e15b27145 the "all_theorems" option and some fixes
paulson
parents: 19875
diff changeset
   508
    HOL_basic_ss addsimps nnf_extra_simps 
7c7e15b27145 the "all_theorems" option and some fixes
paulson
parents: 19875
diff changeset
   509
                 addsimprocs [defALL_regroup,defEX_regroup,neq_simproc,let_simproc];
15872
8336ff711d80 fixed treatment of higher-order simprules
paulson
parents: 15862
diff changeset
   510
21050
d0447a511edb More robust error handling in make_nnf and forward_res
paulson
parents: 21046
diff changeset
   511
fun make_nnf th = case prems_of th of
d0447a511edb More robust error handling in make_nnf and forward_res
paulson
parents: 21046
diff changeset
   512
    [] => th |> rewrite_rule (map safe_mk_meta_eq nnf_simps)
21102
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   513
	     |> simplify nnf_ss  
21050
d0447a511edb More robust error handling in make_nnf and forward_res
paulson
parents: 21046
diff changeset
   514
	     |> make_nnf1
d0447a511edb More robust error handling in make_nnf and forward_res
paulson
parents: 21046
diff changeset
   515
  | _ => raise THM ("make_nnf: premises in argument", 0, [th]);
15581
f07e865d9d40 now checks for higher-order vars
paulson
parents: 15579
diff changeset
   516
15965
f422f8283491 Use of IntInf.int instead of int in most numeric simprocs; avoids
paulson
parents: 15946
diff changeset
   517
(*Pull existential quantifiers to front. This accomplishes Skolemization for
f422f8283491 Use of IntInf.int instead of int in most numeric simprocs; avoids
paulson
parents: 15946
diff changeset
   518
  clauses that arise from a subgoal.*)
9869
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   519
fun skolemize th =
20134
73cb53843190 has_consts renamed to has_conn, now actually parses the first-order formula
paulson
parents: 20119
diff changeset
   520
  if not (has_conns ["Ex"] (prop_of th)) then th
15773
f14ae2432710 Completed integration of reconstruction code. Now finds and displays proofs when used with modified version
quigley
parents: 15736
diff changeset
   521
  else (skolemize (tryres(th, [choice, conj_exD1, conj_exD2,
15679
28eb0fe50533 Integrating the reconstruction files into the building of HOL
quigley
parents: 15653
diff changeset
   522
                              disj_exD, disj_exD1, disj_exD2])))
9869
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   523
    handle THM _ =>
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   524
        skolemize (forward_res skolemize
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   525
                   (tryres (th, [conj_forward, disj_forward, all_forward])))
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   526
    handle THM _ => forward_res skolemize (th RS ex_forward);
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   527
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   528
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   529
(*Make clauses from a list of theorems, previously Skolemized and put into nnf.
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   530
  The resulting clauses are HOL disjunctions.*)
9869
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   531
fun make_clauses ths =
15998
bc916036cf84 new cnf function taking Skolemization theorems as an extra argument
paulson
parents: 15965
diff changeset
   532
    (sort_clauses (map (generalize o nodups) (foldr (cnf[]) [] ths)));
15773
f14ae2432710 Completed integration of reconstruction code. Now finds and displays proofs when used with modified version
quigley
parents: 15736
diff changeset
   533
16563
a92f96951355 meson method taking an argument list
paulson
parents: 16173
diff changeset
   534
(*Convert a list of clauses (disjunctions) to Horn clauses (contrapositives)*)
9869
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   535
fun make_horns ths =
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   536
    name_thms "Horn#"
22360
26ead7ed4f4b moved eq_thm etc. to structure Thm in Pure/more_thm.ML;
wenzelm
parents: 22130
diff changeset
   537
      (distinct Thm.eq_thm_prop (foldr (add_contras clause_rules) [] ths));
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   538
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   539
(*Could simply use nprems_of, which would count remaining subgoals -- no
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   540
  discrimination as to their size!  With BEST_FIRST, fails for problem 41.*)
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   541
9869
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   542
fun best_prolog_tac sizef horns =
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   543
    BEST_FIRST (has_fewer_prems 1, sizef) (prolog_step_tac horns 1);
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   544
9869
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   545
fun depth_prolog_tac horns =
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   546
    DEPTH_FIRST (has_fewer_prems 1) (prolog_step_tac horns 1);
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   547
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   548
(*Return all negative clauses, as possible goal clauses*)
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   549
fun gocls cls = name_thms "Goal#" (map make_goal (neg_clauses cls));
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   550
15008
5abd18710a1f new method for explicit classical resolution
paulson
parents: 14890
diff changeset
   551
fun skolemize_prems_tac prems =
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   552
    cut_facts_tac (map (skolemize o make_nnf) prems)  THEN'
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   553
    REPEAT o (etac exE);
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   554
22546
c40d7ab8cbc5 MESON tactical takes an additional argument: the clausification function.
paulson
parents: 22515
diff changeset
   555
(*Basis of all meson-tactics.  Supplies cltac with clauses: HOL disjunctions.
c40d7ab8cbc5 MESON tactical takes an additional argument: the clausification function.
paulson
parents: 22515
diff changeset
   556
  Function mkcl converts theorems to clauses.*)
c40d7ab8cbc5 MESON tactical takes an additional argument: the clausification function.
paulson
parents: 22515
diff changeset
   557
fun MESON mkcl cltac i st = 
16588
8de758143786 stricter first-order check for meson
paulson
parents: 16563
diff changeset
   558
  SELECT_GOAL
23590
ad95084a5c63 renamed ObjectLogic.atomize_tac to ObjectLogic.atomize_prems_tac;
wenzelm
parents: 23552
diff changeset
   559
    (EVERY [ObjectLogic.atomize_prems_tac 1,
23552
6403d06abe25 to handle non-atomic assumptions
paulson
parents: 23440
diff changeset
   560
            rtac ccontr 1,
16588
8de758143786 stricter first-order check for meson
paulson
parents: 16563
diff changeset
   561
	    METAHYPS (fn negs =>
8de758143786 stricter first-order check for meson
paulson
parents: 16563
diff changeset
   562
		      EVERY1 [skolemize_prems_tac negs,
22724
3002683a6e0f Fixes for proof reconstruction, especially involving abstractions and definitions
paulson
parents: 22646
diff changeset
   563
			      METAHYPS (cltac o mkcl)]) 1]) i st
3002683a6e0f Fixes for proof reconstruction, especially involving abstractions and definitions
paulson
parents: 22646
diff changeset
   564
  handle THM _ => no_tac st;	(*probably from make_meta_clause, not first-order*)
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   565
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   566
(** Best-first search versions **)
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   567
16563
a92f96951355 meson method taking an argument list
paulson
parents: 16173
diff changeset
   568
(*ths is a list of additional clauses (HOL disjunctions) to use.*)
9869
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   569
fun best_meson_tac sizef =
22546
c40d7ab8cbc5 MESON tactical takes an additional argument: the clausification function.
paulson
parents: 22515
diff changeset
   570
  MESON make_clauses 
c40d7ab8cbc5 MESON tactical takes an additional argument: the clausification function.
paulson
parents: 22515
diff changeset
   571
    (fn cls =>
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   572
         THEN_BEST_FIRST (resolve_tac (gocls cls) 1)
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   573
                         (has_fewer_prems 1, sizef)
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   574
                         (prolog_step_tac (make_horns cls) 1));
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   575
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   576
(*First, breaks the goal into independent units*)
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   577
val safe_best_meson_tac =
23894
1a4167d761ac tactics: avoid dynamic reference to accidental theory context (via ML_Context.the_context etc.);
wenzelm
parents: 23590
diff changeset
   578
     SELECT_GOAL (TRY (CLASET safe_tac) THEN
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   579
                  TRYALL (best_meson_tac size_of_subgoals));
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   580
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   581
(** Depth-first search version **)
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   582
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   583
val depth_meson_tac =
22546
c40d7ab8cbc5 MESON tactical takes an additional argument: the clausification function.
paulson
parents: 22515
diff changeset
   584
  MESON make_clauses
c40d7ab8cbc5 MESON tactical takes an additional argument: the clausification function.
paulson
parents: 22515
diff changeset
   585
    (fn cls => EVERY [resolve_tac (gocls cls) 1, depth_prolog_tac (make_horns cls)]);
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   586
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   587
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   588
(** Iterative deepening version **)
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   589
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   590
(*This version does only one inference per call;
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   591
  having only one eq_assume_tac speeds it up!*)
9869
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   592
fun prolog_step_tac' horns =
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   593
    let val (horn0s, hornps) = (*0 subgoals vs 1 or more*)
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   594
            take_prefix Thm.no_prems horns
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   595
        val nrtac = net_resolve_tac horns
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   596
    in  fn i => eq_assume_tac i ORELSE
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   597
                match_tac horn0s i ORELSE  (*no backtracking if unit MATCHES*)
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   598
                ((assume_tac i APPEND nrtac i) THEN check_tac)
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   599
    end;
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   600
9869
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   601
fun iter_deepen_prolog_tac horns =
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   602
    ITER_DEEPEN (has_fewer_prems 1) (prolog_step_tac' horns);
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   603
22546
c40d7ab8cbc5 MESON tactical takes an additional argument: the clausification function.
paulson
parents: 22515
diff changeset
   604
fun iter_deepen_meson_tac ths = MESON make_clauses 
21095
2c9f73fa973c Improved tracing
paulson
parents: 21069
diff changeset
   605
 (fn cls =>
2c9f73fa973c Improved tracing
paulson
parents: 21069
diff changeset
   606
      case (gocls (cls@ths)) of
2c9f73fa973c Improved tracing
paulson
parents: 21069
diff changeset
   607
	   [] => no_tac  (*no goal clauses*)
2c9f73fa973c Improved tracing
paulson
parents: 21069
diff changeset
   608
	 | goes => 
2c9f73fa973c Improved tracing
paulson
parents: 21069
diff changeset
   609
	     let val horns = make_horns (cls@ths)
22130
0906fd95e0b5 Output.debug: non-strict;
wenzelm
parents: 21999
diff changeset
   610
	         val _ =
0906fd95e0b5 Output.debug: non-strict;
wenzelm
parents: 21999
diff changeset
   611
	             Output.debug (fn () => ("meson method called:\n" ^ 
21095
2c9f73fa973c Improved tracing
paulson
parents: 21069
diff changeset
   612
	     	                  space_implode "\n" (map string_of_thm (cls@ths)) ^ 
2c9f73fa973c Improved tracing
paulson
parents: 21069
diff changeset
   613
	     	                  "\nclauses:\n" ^ 
22130
0906fd95e0b5 Output.debug: non-strict;
wenzelm
parents: 21999
diff changeset
   614
	     	                  space_implode "\n" (map string_of_thm horns)))
21095
2c9f73fa973c Improved tracing
paulson
parents: 21069
diff changeset
   615
	     in THEN_ITER_DEEPEN (resolve_tac goes 1) (has_fewer_prems 1) (prolog_step_tac' horns)
2c9f73fa973c Improved tracing
paulson
parents: 21069
diff changeset
   616
	     end
2c9f73fa973c Improved tracing
paulson
parents: 21069
diff changeset
   617
 );
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   618
16563
a92f96951355 meson method taking an argument list
paulson
parents: 16173
diff changeset
   619
fun meson_claset_tac ths cs =
a92f96951355 meson method taking an argument list
paulson
parents: 16173
diff changeset
   620
  SELECT_GOAL (TRY (safe_tac cs) THEN TRYALL (iter_deepen_meson_tac ths));
9869
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   621
16563
a92f96951355 meson method taking an argument list
paulson
parents: 16173
diff changeset
   622
val meson_tac = CLASET' (meson_claset_tac []);
9869
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   623
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   624
14813
826edbc317e6 new skolemize_tac and skolemize method
paulson
parents: 14763
diff changeset
   625
(**** Code to support ordinary resolution, rather than Model Elimination ****)
14744
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   626
15008
5abd18710a1f new method for explicit classical resolution
paulson
parents: 14890
diff changeset
   627
(*Convert a list of clauses (disjunctions) to meta-level clauses (==>), 
5abd18710a1f new method for explicit classical resolution
paulson
parents: 14890
diff changeset
   628
  with no contrapositives, for ordinary resolution.*)
14744
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   629
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   630
(*Rules to convert the head literal into a negated assumption. If the head
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   631
  literal is already negated, then using notEfalse instead of notEfalse'
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   632
  prevents a double negation.*)
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   633
val notEfalse = read_instantiate [("R","False")] notE;
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   634
val notEfalse' = rotate_prems 1 notEfalse;
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   635
15448
fb7b8313a20d negate_nead (???) changed to negated_asm_of_head
paulson
parents: 15151
diff changeset
   636
fun negated_asm_of_head th = 
14744
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   637
    th RS notEfalse handle THM _ => th RS notEfalse';
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   638
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   639
(*Converting one clause*)
22646
197f6c4ff9a5 Zero variable indexes in clauses
paulson
parents: 22546
diff changeset
   640
val make_meta_clause = 
197f6c4ff9a5 Zero variable indexes in clauses
paulson
parents: 22546
diff changeset
   641
  zero_var_indexes o negated_asm_of_head o make_horn resolution_clause_rules;
21102
7f2ebe5c5b72 Conversion to clause form now tolerates Boolean variables without looping.
paulson
parents: 21095
diff changeset
   642
  
14744
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   643
fun make_meta_clauses ths =
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   644
    name_thms "MClause#"
22360
26ead7ed4f4b moved eq_thm etc. to structure Thm in Pure/more_thm.ML;
wenzelm
parents: 22130
diff changeset
   645
      (distinct Thm.eq_thm_prop (map make_meta_clause ths));
14744
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   646
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   647
(*Permute a rule's premises to move the i-th premise to the last position.*)
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   648
fun make_last i th =
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   649
  let val n = nprems_of th 
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   650
  in  if 1 <= i andalso i <= n 
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   651
      then Thm.permute_prems (i-1) 1 th
15118
e2bd080c7975 make_clauses now meta
paulson
parents: 15032
diff changeset
   652
      else raise THM("select_literal", i, [th])
14744
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   653
  end;
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   654
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   655
(*Maps a rule that ends "... ==> P ==> False" to "... ==> ~P" while suppressing
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   656
  double-negations.*)
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   657
val negate_head = rewrite_rule [atomize_not, not_not RS eq_reflection];
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   658
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   659
(*Maps the clause  [P1,...Pn]==>False to [P1,...,P(i-1),P(i+1),...Pn] ==> ~P*)
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   660
fun select_literal i cl = negate_head (make_last i cl);
7ccfc167e451 clauses for ordinary resolution
paulson
parents: 14733
diff changeset
   661
18508
paulson
parents: 18405
diff changeset
   662
14813
826edbc317e6 new skolemize_tac and skolemize method
paulson
parents: 14763
diff changeset
   663
(*Top-level Skolemization. Allows part of the conversion to clauses to be
826edbc317e6 new skolemize_tac and skolemize method
paulson
parents: 14763
diff changeset
   664
  expressed as a tactic (or Isar method).  Each assumption of the selected 
826edbc317e6 new skolemize_tac and skolemize method
paulson
parents: 14763
diff changeset
   665
  goal is converted to NNF and then its existential quantifiers are pulled
826edbc317e6 new skolemize_tac and skolemize method
paulson
parents: 14763
diff changeset
   666
  to the front. Finally, all existential quantifiers are eliminated, 
826edbc317e6 new skolemize_tac and skolemize method
paulson
parents: 14763
diff changeset
   667
  leaving !!-quantified variables. Perhaps Safe_tac should follow, but it
826edbc317e6 new skolemize_tac and skolemize method
paulson
parents: 14763
diff changeset
   668
  might generate many subgoals.*)
18194
940515d2fa26 -- removed "check_is_fol" from "make_nnf" so that the NNF procedure doesn't check whether a thm is FOL.
mengj
parents: 18175
diff changeset
   669
19204
b8f7de7ef629 Tidying, and getting rid of SELECT_GOAL (as it does something different now)
paulson
parents: 19154
diff changeset
   670
fun skolemize_tac i st = 
b8f7de7ef629 Tidying, and getting rid of SELECT_GOAL (as it does something different now)
paulson
parents: 19154
diff changeset
   671
  let val ts = Logic.strip_assums_hyp (List.nth (prems_of st, i-1))
b8f7de7ef629 Tidying, and getting rid of SELECT_GOAL (as it does something different now)
paulson
parents: 19154
diff changeset
   672
  in 
b8f7de7ef629 Tidying, and getting rid of SELECT_GOAL (as it does something different now)
paulson
parents: 19154
diff changeset
   673
     EVERY' [METAHYPS
15773
f14ae2432710 Completed integration of reconstruction code. Now finds and displays proofs when used with modified version
quigley
parents: 15736
diff changeset
   674
	    (fn hyps => (cut_facts_tac (map (skolemize o make_nnf) hyps) 1
14813
826edbc317e6 new skolemize_tac and skolemize method
paulson
parents: 14763
diff changeset
   675
                         THEN REPEAT (etac exE 1))),
19204
b8f7de7ef629 Tidying, and getting rid of SELECT_GOAL (as it does something different now)
paulson
parents: 19154
diff changeset
   676
            REPEAT_DETERM_N (length ts) o (etac thin_rl)] i st
b8f7de7ef629 Tidying, and getting rid of SELECT_GOAL (as it does something different now)
paulson
parents: 19154
diff changeset
   677
  end
b8f7de7ef629 Tidying, and getting rid of SELECT_GOAL (as it does something different now)
paulson
parents: 19154
diff changeset
   678
  handle Subscript => Seq.empty;
18194
940515d2fa26 -- removed "check_is_fol" from "make_nnf" so that the NNF procedure doesn't check whether a thm is FOL.
mengj
parents: 18175
diff changeset
   679
9840
9dfcb0224f8c meson.ML moved from HOL/ex to HOL/Tools: meson_tac installed by default
paulson
parents:
diff changeset
   680
end;
9869
95dca9f991f2 improved meson setup;
wenzelm
parents: 9840
diff changeset
   681
15579
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   682
structure BasicMeson: BASIC_MESON = Meson;
32bee18c675f Tools/meson.ML: signature, structure and "open" rather than "local"
paulson
parents: 15574
diff changeset
   683
open BasicMeson;