wenzelm@4078
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(* Title: Provers/blast.ML
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paulson@2894
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ID: $Id$
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Author: Lawrence C Paulson, Cambridge University Computer Laboratory
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Copyright 1997 University of Cambridge
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Generic tableau prover with proof reconstruction
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SKOLEMIZES ReplaceI WRONGLY: allow new vars in prems, or forbid such rules??
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Needs explicit instantiation of assumptions?
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paulson@2924
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Blast_tac is often more powerful than fast_tac, but has some limitations.
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paulson@2924
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Blast_tac...
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oheimb@4651
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* ignores wrappers (addss, addbefore, addafter, addWrapper, ...);
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oheimb@4651
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this restriction is intrinsic
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paulson@2894
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* ignores elimination rules that don't have the correct format
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(conclusion must be a formula variable)
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* ignores types, which can make HOL proofs fail
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paulson@2924
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* rules must not require higher-order unification, e.g. apply_type in ZF
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paulson@2924
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+ message "Function Var's argument not a bound variable" relates to this
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* its proof strategy is more general but can actually be slower
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Known problems:
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paulson@3092
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"Recursive" chains of rules can sometimes exclude other unsafe formulae
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from expansion. This happens because newly-created formulae always
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have priority over existing ones. But obviously recursive rules
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such as transitivity are treated specially to prevent this. Sometimes
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paulson@5343
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the formulae get into the wrong order (see WRONG below).
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paulson@3021
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paulson@2952
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With overloading:
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Calls to Blast.overloaded (see HOL/Set.ML for examples) are needed
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to tell Blast_tac when to retain some type information. Make sure
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you know the constant's internal name, which might be "op <=" or
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"Relation.op ^^".
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paulson@2952
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paulson@2924
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With substition for equalities (hyp_subst_tac):
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When substitution affects a haz formula or literal, it is moved
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back to the list of safe formulae.
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But there's no way of putting it in the right place. A "moved" or
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"no DETERM" flag would prevent proofs failing here.
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*)
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(*Should be a type abbreviation?*)
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type netpair = (int*(bool*thm)) Net.net * (int*(bool*thm)) Net.net;
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(*Assumptions about constants:
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--The negation symbol is "Not"
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--The equality symbol is "op ="
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--The is-true judgement symbol is "Trueprop"
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--There are no constants named "*Goal* or "*False*"
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*)
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signature BLAST_DATA =
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sig
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type claset
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val notE : thm (* [| ~P; P |] ==> R *)
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val ccontr : thm
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val contr_tac : int -> tactic
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val dup_intr : thm -> thm
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val hyp_subst_tac : bool ref -> int -> tactic
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val claset : unit -> claset
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val rep_cs : (* dependent on classical.ML *)
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claset -> {safeIs: thm list, safeEs: thm list,
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hazIs: thm list, hazEs: thm list,
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xtraIs: thm list, xtraEs: thm list,
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swrappers: (string * wrapper) list,
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uwrappers: (string * wrapper) list,
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safe0_netpair: netpair, safep_netpair: netpair,
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haz_netpair: netpair, dup_netpair: netpair, xtra_netpair: netpair}
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wenzelm@7272
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val cla_modifiers: (Args.T list -> (Method.modifier * Args.T list)) list
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val cla_meth': (claset -> int -> tactic) -> thm list -> Proof.context -> Proof.method
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end;
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signature BLAST =
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sig
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type claset
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exception TRANS of string (*reports translation errors*)
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datatype term =
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Const of string
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| TConst of string * term
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| Skolem of string * term option ref list
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| Free of string
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| Var of term option ref
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| Bound of int
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| Abs of string*term
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| $ of term*term;
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type branch
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val depth_tac : claset -> int -> int -> tactic
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val blast_tac : claset -> int -> tactic
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val Blast_tac : int -> tactic
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val overloaded : string * (Term.typ -> Term.typ) -> unit
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val setup : (theory -> theory) list
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(*debugging tools*)
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val stats : bool ref
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val trace : bool ref
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val fullTrace : branch list list ref
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val fromType : (indexname * term) list ref -> Term.typ -> term
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val fromTerm : Term.term -> term
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val fromSubgoal : Term.term -> term
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val instVars : term -> (unit -> unit)
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val toTerm : int -> term -> Term.term
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val readGoal : Sign.sg -> string -> term
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val tryInThy : theory -> int -> string ->
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(int->tactic) list * branch list list * (int*int*exn) list
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val trygl : claset -> int -> int ->
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(int->tactic) list * branch list list * (int*int*exn) list
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val Trygl : int -> int ->
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(int->tactic) list * branch list list * (int*int*exn) list
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val normBr : branch -> branch
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end;
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functor BlastFun(Data: BLAST_DATA) : BLAST =
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struct
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type claset = Data.claset;
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val trace = ref false
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and stats = ref false; (*for runtime and search statistics*)
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datatype term =
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Const of string
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| TConst of string * term (*type of overloaded constant--as a term!*)
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| Skolem of string * term option ref list
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| Free of string
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| Var of term option ref
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| Bound of int
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| Abs of string*term
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| op $ of term*term;
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(** Basic syntactic operations **)
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fun is_Var (Var _) = true
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| is_Var _ = false;
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fun dest_Var (Var x) = x;
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fun rand (f$x) = x;
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(* maps (f, [t1,...,tn]) to f(t1,...,tn) *)
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val list_comb : term * term list -> term = foldl (op $);
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(* maps f(t1,...,tn) to (f, [t1,...,tn]) ; naturally tail-recursive*)
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fun strip_comb u : term * term list =
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let fun stripc (f$t, ts) = stripc (f, t::ts)
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| stripc x = x
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in stripc(u,[]) end;
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(* maps f(t1,...,tn) to f , which is never a combination *)
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fun head_of (f$t) = head_of f
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| head_of u = u;
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(** Particular constants **)
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fun negate P = Const"Not" $ P;
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fun mkGoal P = Const"*Goal*" $ P;
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fun isGoal (Const"*Goal*" $ _) = true
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| isGoal _ = false;
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val Trueprop = Term.Const("Trueprop", Type("o",[])-->propT);
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fun mk_tprop P = Term.$ (Trueprop, P);
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fun isTrueprop (Term.Const("Trueprop",_)) = true
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| isTrueprop _ = false;
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(*** Dealing with overloaded constants ***)
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(*alist is a map from TVar names to Vars. We need to unify the TVars
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faithfully in order to track overloading*)
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fun fromType alist (Term.Type(a,Ts)) = list_comb (Const a,
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map (fromType alist) Ts)
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| fromType alist (Term.TFree(a,_)) = Free a
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paulson@4065
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| fromType alist (Term.TVar (ixn,_)) =
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paulson@4065
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(case (assoc_string_int(!alist,ixn)) of
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None => let val t' = Var(ref None)
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in alist := (ixn, t') :: !alist; t'
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end
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| Some v => v)
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local
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val overloads = ref ([]: (string * (Term.typ -> Term.typ)) list)
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in
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fun overloaded arg = (overloads := arg :: (!overloads));
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(*Convert a possibly overloaded Term.Const to a Blast.Const or Blast.TConst,
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converting its type to a Blast.term in the latter case.*)
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fun fromConst alist (a,T) =
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case assoc_string (!overloads, a) of
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None => Const a (*not overloaded*)
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| Some f =>
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let val T' = f T
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handle Match => error
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("Blast_tac: unexpected type for overloaded constant " ^ a)
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in TConst(a, fromType alist T') end;
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end;
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(*Tests whether 2 terms are alpha-convertible; chases instantiations*)
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fun (Const a) aconv (Const b) = a=b
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| (TConst (a,ta)) aconv (TConst (b,tb)) = a=b andalso ta aconv tb
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| (Skolem (a,_)) aconv (Skolem (b,_)) = a=b (*arglists must then be equal*)
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| (Free a) aconv (Free b) = a=b
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| (Var(ref(Some t))) aconv u = t aconv u
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| t aconv (Var(ref(Some u))) = t aconv u
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| (Var v) aconv (Var w) = v=w (*both Vars are un-assigned*)
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| (Bound i) aconv (Bound j) = i=j
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| (Abs(_,t)) aconv (Abs(_,u)) = t aconv u
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paulson@2854
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| (f$t) aconv (g$u) = (f aconv g) andalso (t aconv u)
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| _ aconv _ = false;
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fun mem_term (_, []) = false
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| mem_term (t, t'::ts) = t aconv t' orelse mem_term(t,ts);
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fun ins_term(t,ts) = if mem_term(t,ts) then ts else t :: ts;
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fun mem_var (v: term option ref, []) = false
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| mem_var (v, v'::vs) = v=v' orelse mem_var(v,vs);
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fun ins_var(v,vs) = if mem_var(v,vs) then vs else v :: vs;
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(** Vars **)
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(*Accumulates the Vars in the term, suppressing duplicates*)
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fun add_term_vars (Skolem(a,args), vars) = add_vars_vars(args,vars)
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| add_term_vars (Var (v as ref None), vars) = ins_var (v, vars)
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| add_term_vars (Var (ref (Some u)), vars) = add_term_vars(u,vars)
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paulson@4065
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| add_term_vars (TConst (_,t), vars) = add_term_vars(t,vars)
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paulson@2854
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| add_term_vars (Abs (_,body), vars) = add_term_vars(body,vars)
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| add_term_vars (f$t, vars) = add_term_vars (f, add_term_vars(t, vars))
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| add_term_vars (_, vars) = vars
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(*Term list version. [The fold functionals are slow]*)
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and add_terms_vars ([], vars) = vars
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| add_terms_vars (t::ts, vars) = add_terms_vars (ts, add_term_vars(t,vars))
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(*Var list version.*)
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and add_vars_vars ([], vars) = vars
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paulson@2854
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| add_vars_vars (ref (Some u) :: vs, vars) =
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paulson@2854
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add_vars_vars (vs, add_term_vars(u,vars))
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| add_vars_vars (v::vs, vars) = (*v must be a ref None*)
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add_vars_vars (vs, ins_var (v, vars));
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(*Chase assignments in "vars"; return a list of unassigned variables*)
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fun vars_in_vars vars = add_vars_vars(vars,[]);
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(*increment a term's non-local bound variables
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inc is increment for bound variables
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lev is level at which a bound variable is considered 'loose'*)
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fun incr_bv (inc, lev, u as Bound i) = if i>=lev then Bound(i+inc) else u
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| incr_bv (inc, lev, Abs(a,body)) = Abs(a, incr_bv(inc,lev+1,body))
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paulson@2854
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| incr_bv (inc, lev, f$t) = incr_bv(inc,lev,f) $ incr_bv(inc,lev,t)
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paulson@2854
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| incr_bv (inc, lev, u) = u;
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fun incr_boundvars 0 t = t
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| incr_boundvars inc t = incr_bv(inc,0,t);
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(*Accumulate all 'loose' bound vars referring to level 'lev' or beyond.
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(Bound 0) is loose at level 0 *)
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fun add_loose_bnos (Bound i, lev, js) = if i<lev then js
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else (i-lev) ins_int js
|
paulson@2854
|
276 |
| add_loose_bnos (Abs (_,t), lev, js) = add_loose_bnos (t, lev+1, js)
|
paulson@2854
|
277 |
| add_loose_bnos (f$t, lev, js) =
|
paulson@2854
|
278 |
add_loose_bnos (f, lev, add_loose_bnos (t, lev, js))
|
paulson@2854
|
279 |
| add_loose_bnos (_, _, js) = js;
|
paulson@2854
|
280 |
|
paulson@2854
|
281 |
fun loose_bnos t = add_loose_bnos (t, 0, []);
|
paulson@2854
|
282 |
|
paulson@2854
|
283 |
fun subst_bound (arg, t) : term =
|
paulson@2854
|
284 |
let fun subst (t as Bound i, lev) =
|
paulson@2854
|
285 |
if i<lev then t (*var is locally bound*)
|
paulson@2854
|
286 |
else if i=lev then incr_boundvars lev arg
|
paulson@2854
|
287 |
else Bound(i-1) (*loose: change it*)
|
paulson@2854
|
288 |
| subst (Abs(a,body), lev) = Abs(a, subst(body,lev+1))
|
paulson@2854
|
289 |
| subst (f$t, lev) = subst(f,lev) $ subst(t,lev)
|
paulson@2854
|
290 |
| subst (t,lev) = t
|
paulson@2854
|
291 |
in subst (t,0) end;
|
paulson@2854
|
292 |
|
paulson@2854
|
293 |
|
paulson@3101
|
294 |
(*Normalize...but not the bodies of ABSTRACTIONS*)
|
paulson@2854
|
295 |
fun norm t = case t of
|
paulson@2952
|
296 |
Skolem (a,args) => Skolem(a, vars_in_vars args)
|
paulson@4065
|
297 |
| TConst(a,aT) => TConst(a, norm aT)
|
paulson@2854
|
298 |
| (Var (ref None)) => t
|
paulson@2854
|
299 |
| (Var (ref (Some u))) => norm u
|
paulson@2854
|
300 |
| (f $ u) => (case norm f of
|
paulson@3101
|
301 |
Abs(_,body) => norm (subst_bound (u, body))
|
paulson@3101
|
302 |
| nf => nf $ norm u)
|
paulson@2854
|
303 |
| _ => t;
|
paulson@2854
|
304 |
|
paulson@2854
|
305 |
|
paulson@2854
|
306 |
(*Weak (one-level) normalize for use in unification*)
|
paulson@2854
|
307 |
fun wkNormAux t = case t of
|
paulson@2854
|
308 |
(Var v) => (case !v of
|
paulson@2854
|
309 |
Some u => wkNorm u
|
paulson@2854
|
310 |
| None => t)
|
paulson@2854
|
311 |
| (f $ u) => (case wkNormAux f of
|
paulson@2854
|
312 |
Abs(_,body) => wkNorm (subst_bound (u, body))
|
paulson@2854
|
313 |
| nf => nf $ u)
|
paulson@2952
|
314 |
| Abs (a,body) => (*eta-contract if possible*)
|
paulson@2952
|
315 |
(case wkNormAux body of
|
paulson@2952
|
316 |
nb as (f $ t) =>
|
paulson@2952
|
317 |
if (0 mem_int loose_bnos f) orelse wkNorm t <> Bound 0
|
paulson@2952
|
318 |
then Abs(a,nb)
|
paulson@2952
|
319 |
else wkNorm (incr_boundvars ~1 f)
|
paulson@3092
|
320 |
| nb => Abs (a,nb))
|
paulson@2854
|
321 |
| _ => t
|
paulson@2854
|
322 |
and wkNorm t = case head_of t of
|
paulson@2854
|
323 |
Const _ => t
|
paulson@4065
|
324 |
| TConst _ => t
|
paulson@2854
|
325 |
| Skolem(a,args) => t
|
paulson@2854
|
326 |
| Free _ => t
|
paulson@2854
|
327 |
| _ => wkNormAux t;
|
paulson@2854
|
328 |
|
paulson@2854
|
329 |
|
paulson@5734
|
330 |
(*Does variable v occur in u? For unification.
|
paulson@5734
|
331 |
Dangling bound vars are also forbidden.*)
|
paulson@2854
|
332 |
fun varOccur v =
|
paulson@5734
|
333 |
let fun occL lev [] = false (*same as (exists occ), but faster*)
|
paulson@5734
|
334 |
| occL lev (u::us) = occ lev u orelse occL lev us
|
paulson@5734
|
335 |
and occ lev (Var w) =
|
paulson@2854
|
336 |
v=w orelse
|
paulson@2854
|
337 |
(case !w of None => false
|
paulson@5734
|
338 |
| Some u => occ lev u)
|
paulson@5734
|
339 |
| occ lev (Skolem(_,args)) = occL lev (map Var args)
|
paulson@5734
|
340 |
(*ignore TConst, since term variables can't occur in types (?) *)
|
paulson@5734
|
341 |
| occ lev (Bound i) = lev <= i
|
paulson@5734
|
342 |
| occ lev (Abs(_,u)) = occ (lev+1) u
|
paulson@5734
|
343 |
| occ lev (f$u) = occ lev u orelse occ lev f
|
paulson@5734
|
344 |
| occ lev _ = false;
|
paulson@5734
|
345 |
in occ 0 end;
|
paulson@2854
|
346 |
|
paulson@2854
|
347 |
exception UNIFY;
|
paulson@2854
|
348 |
|
paulson@2854
|
349 |
val trail = ref [] : term option ref list ref;
|
paulson@2854
|
350 |
val ntrail = ref 0;
|
paulson@2854
|
351 |
|
paulson@2854
|
352 |
|
paulson@2854
|
353 |
(*Restore the trail to some previous state: for backtracking*)
|
paulson@2854
|
354 |
fun clearTo n =
|
paulson@3083
|
355 |
while !ntrail<>n do
|
paulson@2854
|
356 |
(hd(!trail) := None;
|
paulson@2854
|
357 |
trail := tl (!trail);
|
paulson@2854
|
358 |
ntrail := !ntrail - 1);
|
paulson@2854
|
359 |
|
paulson@2854
|
360 |
|
paulson@2854
|
361 |
(*First-order unification with bound variables.
|
paulson@2854
|
362 |
"vars" is a list of variables local to the rule and NOT to be put
|
paulson@2854
|
363 |
on the trail (no point in doing so)
|
paulson@2854
|
364 |
*)
|
paulson@4065
|
365 |
fun unify(vars,t,u) =
|
paulson@2854
|
366 |
let val n = !ntrail
|
paulson@2854
|
367 |
fun update (t as Var v, u) =
|
paulson@2854
|
368 |
if t aconv u then ()
|
paulson@2854
|
369 |
else if varOccur v u then raise UNIFY
|
paulson@2854
|
370 |
else if mem_var(v, vars) then v := Some u
|
paulson@2854
|
371 |
else (*avoid updating Vars in the branch if possible!*)
|
paulson@2854
|
372 |
if is_Var u andalso mem_var(dest_Var u, vars)
|
paulson@2854
|
373 |
then dest_Var u := Some t
|
paulson@2854
|
374 |
else (v := Some u;
|
paulson@2854
|
375 |
trail := v :: !trail; ntrail := !ntrail + 1)
|
paulson@2854
|
376 |
fun unifyAux (t,u) =
|
paulson@2854
|
377 |
case (wkNorm t, wkNorm u) of
|
paulson@2854
|
378 |
(nt as Var v, nu) => update(nt,nu)
|
paulson@2854
|
379 |
| (nu, nt as Var v) => update(nt,nu)
|
paulson@4065
|
380 |
| (TConst(a,at), TConst(b,bt)) => if a=b then unifyAux(at,bt)
|
paulson@4065
|
381 |
else raise UNIFY
|
paulson@2854
|
382 |
| (Abs(_,t'), Abs(_,u')) => unifyAux(t',u')
|
paulson@2854
|
383 |
(*NB: can yield unifiers having dangling Bound vars!*)
|
paulson@2854
|
384 |
| (f$t', g$u') => (unifyAux(f,g); unifyAux(t',u'))
|
paulson@2854
|
385 |
| (nt, nu) => if nt aconv nu then () else raise UNIFY
|
paulson@3083
|
386 |
in (unifyAux(t,u); true) handle UNIFY => (clearTo n; false)
|
paulson@2854
|
387 |
end;
|
paulson@2854
|
388 |
|
paulson@2854
|
389 |
|
paulson@4065
|
390 |
(*Convert from "real" terms to prototerms; eta-contract
|
paulson@4065
|
391 |
Code is duplicated with fromSubgoal. Correct this?*)
|
paulson@4065
|
392 |
fun fromTerm t =
|
paulson@4065
|
393 |
let val alistVar = ref []
|
paulson@4065
|
394 |
and alistTVar = ref []
|
paulson@4065
|
395 |
fun from (Term.Const aT) = fromConst alistTVar aT
|
paulson@2854
|
396 |
| from (Term.Free (a,_)) = Free a
|
paulson@2854
|
397 |
| from (Term.Bound i) = Bound i
|
paulson@2854
|
398 |
| from (Term.Var (ixn,T)) =
|
paulson@4065
|
399 |
(case (assoc_string_int(!alistVar,ixn)) of
|
paulson@2854
|
400 |
None => let val t' = Var(ref None)
|
paulson@4065
|
401 |
in alistVar := (ixn, t') :: !alistVar; t'
|
paulson@2854
|
402 |
end
|
paulson@4065
|
403 |
| Some v => v)
|
paulson@2854
|
404 |
| from (Term.Abs (a,_,u)) =
|
paulson@2854
|
405 |
(case from u of
|
paulson@2854
|
406 |
u' as (f $ Bound 0) =>
|
paulson@2854
|
407 |
if (0 mem_int loose_bnos f) then Abs(a,u')
|
paulson@2854
|
408 |
else incr_boundvars ~1 f
|
paulson@2854
|
409 |
| u' => Abs(a,u'))
|
paulson@2854
|
410 |
| from (Term.$ (f,u)) = from f $ from u
|
paulson@2854
|
411 |
in from t end;
|
paulson@2854
|
412 |
|
paulson@4065
|
413 |
(*A debugging function: replaces all Vars by dummy Frees for visual inspection
|
paulson@4065
|
414 |
of whether they are distinct. Function revert undoes the assignments.*)
|
paulson@4065
|
415 |
fun instVars t =
|
paulson@4065
|
416 |
let val name = ref "A"
|
paulson@4065
|
417 |
val updated = ref []
|
paulson@4065
|
418 |
fun inst (TConst(a,t)) = inst t
|
paulson@4065
|
419 |
| inst (Var(v as ref None)) = (updated := v :: (!updated);
|
paulson@4065
|
420 |
v := Some (Free ("?" ^ !name));
|
paulson@4065
|
421 |
name := bump_string (!name))
|
paulson@4065
|
422 |
| inst (Abs(a,t)) = inst t
|
paulson@4065
|
423 |
| inst (f $ u) = (inst f; inst u)
|
paulson@4065
|
424 |
| inst _ = ()
|
paulson@4065
|
425 |
fun revert() = seq (fn v => v:=None) (!updated)
|
paulson@4065
|
426 |
in inst t; revert end;
|
paulson@4065
|
427 |
|
paulson@4065
|
428 |
|
paulson@2854
|
429 |
(* A1==>...An==>B goes to [A1,...,An], where B is not an implication *)
|
paulson@2854
|
430 |
fun strip_imp_prems (Const"==>" $ (Const"Trueprop" $ A) $ B) =
|
paulson@2854
|
431 |
A :: strip_imp_prems B
|
paulson@2854
|
432 |
| strip_imp_prems (Const"==>" $ A $ B) = A :: strip_imp_prems B
|
paulson@2854
|
433 |
| strip_imp_prems _ = [];
|
paulson@2854
|
434 |
|
paulson@2854
|
435 |
(* A1==>...An==>B goes to B, where B is not an implication *)
|
paulson@2854
|
436 |
fun strip_imp_concl (Const"==>" $ A $ B) = strip_imp_concl B
|
paulson@2854
|
437 |
| strip_imp_concl (Const"Trueprop" $ A) = A
|
paulson@2854
|
438 |
| strip_imp_concl A = A : term;
|
paulson@2854
|
439 |
|
paulson@2854
|
440 |
|
paulson@2854
|
441 |
(*** Conversion of Elimination Rules to Tableau Operations ***)
|
paulson@2854
|
442 |
|
paulson@2854
|
443 |
(*The conclusion becomes the goal/negated assumption *False*: delete it!*)
|
paulson@2854
|
444 |
fun squash_nots [] = []
|
paulson@2854
|
445 |
| squash_nots (Const "*Goal*" $ (Var (ref (Some (Const"*False*")))) :: Ps) =
|
paulson@2854
|
446 |
squash_nots Ps
|
paulson@2854
|
447 |
| squash_nots (Const "Not" $ (Var (ref (Some (Const"*False*")))) :: Ps) =
|
paulson@2854
|
448 |
squash_nots Ps
|
paulson@2854
|
449 |
| squash_nots (P::Ps) = P :: squash_nots Ps;
|
paulson@2854
|
450 |
|
paulson@2854
|
451 |
fun skoPrem vars (Const "all" $ Abs (_, P)) =
|
paulson@2854
|
452 |
skoPrem vars (subst_bound (Skolem (gensym "S_", vars), P))
|
paulson@2854
|
453 |
| skoPrem vars P = P;
|
paulson@2854
|
454 |
|
paulson@2854
|
455 |
fun convertPrem t =
|
paulson@2854
|
456 |
squash_nots (mkGoal (strip_imp_concl t) :: strip_imp_prems t);
|
paulson@2854
|
457 |
|
paulson@2854
|
458 |
(*Expects elimination rules to have a formula variable as conclusion*)
|
paulson@2854
|
459 |
fun convertRule vars t =
|
paulson@2854
|
460 |
let val (P::Ps) = strip_imp_prems t
|
paulson@2854
|
461 |
val Var v = strip_imp_concl t
|
paulson@2854
|
462 |
in v := Some (Const"*False*");
|
paulson@2854
|
463 |
(P, map (convertPrem o skoPrem vars) Ps)
|
paulson@2854
|
464 |
end;
|
paulson@2854
|
465 |
|
paulson@2854
|
466 |
|
paulson@2854
|
467 |
(*Like dup_elim, but puts the duplicated major premise FIRST*)
|
wenzelm@4271
|
468 |
fun rev_dup_elim th = th RSN (2, revcut_rl) |> assumption 2 |> Seq.hd;
|
paulson@2854
|
469 |
|
paulson@2854
|
470 |
|
paulson@4391
|
471 |
(*Rotate the assumptions in all new subgoals for the LIFO discipline*)
|
paulson@4391
|
472 |
local
|
paulson@4391
|
473 |
(*Count new hyps so that they can be rotated*)
|
paulson@4391
|
474 |
fun nNewHyps [] = 0
|
paulson@4391
|
475 |
| nNewHyps (Const "*Goal*" $ _ :: Ps) = nNewHyps Ps
|
paulson@4391
|
476 |
| nNewHyps (P::Ps) = 1 + nNewHyps Ps;
|
paulson@2854
|
477 |
|
paulson@5463
|
478 |
fun rot_tac [] i st = Seq.single st
|
paulson@4391
|
479 |
| rot_tac (0::ks) i st = rot_tac ks (i+1) st
|
paulson@4391
|
480 |
| rot_tac (k::ks) i st = rot_tac ks (i+1) (rotate_rule (~k) i st);
|
paulson@4391
|
481 |
in
|
paulson@4391
|
482 |
fun rot_subgoals_tac (rot, rl) =
|
paulson@4391
|
483 |
rot_tac (if rot then map nNewHyps rl else [])
|
paulson@4391
|
484 |
end;
|
paulson@4391
|
485 |
|
paulson@2854
|
486 |
|
paulson@2999
|
487 |
fun TRACE rl tac st i = if !trace then (prth rl; tac st i) else tac st i;
|
paulson@2854
|
488 |
|
paulson@5343
|
489 |
(*Resolution/matching tactics: if upd then the proof state may be updated.
|
paulson@5343
|
490 |
Matching makes the tactics more deterministic in the presence of Vars.*)
|
paulson@5343
|
491 |
fun emtac upd rl = TRACE rl (if upd then etac rl else ematch_tac [rl]);
|
paulson@5343
|
492 |
fun rmtac upd rl = TRACE rl (if upd then rtac rl else match_tac [rl]);
|
paulson@5343
|
493 |
|
paulson@5343
|
494 |
(*Tableau rule from elimination rule.
|
paulson@5343
|
495 |
Flag "upd" says that the inference updated the branch.
|
paulson@5343
|
496 |
Flag "dup" requests duplication of the affected formula.*)
|
paulson@2854
|
497 |
fun fromRule vars rl =
|
paulson@4065
|
498 |
let val trl = rl |> rep_thm |> #prop |> fromTerm |> convertRule vars
|
paulson@5343
|
499 |
fun tac (upd, dup,rot) i =
|
paulson@5343
|
500 |
emtac upd (if dup then rev_dup_elim rl else rl) i
|
paulson@4391
|
501 |
THEN
|
paulson@4391
|
502 |
rot_subgoals_tac (rot, #2 trl) i
|
paulson@3244
|
503 |
in Option.SOME (trl, tac) end
|
paulson@2924
|
504 |
handle Bind => (*reject: conclusion is not just a variable*)
|
wenzelm@3533
|
505 |
(if !trace then (warning ("ignoring ill-formed elimination rule\n" ^
|
wenzelm@3533
|
506 |
string_of_thm rl))
|
paulson@2924
|
507 |
else ();
|
paulson@3244
|
508 |
Option.NONE);
|
paulson@2854
|
509 |
|
paulson@2854
|
510 |
|
paulson@3101
|
511 |
(*** Conversion of Introduction Rules ***)
|
paulson@2854
|
512 |
|
paulson@2854
|
513 |
fun convertIntrPrem t = mkGoal (strip_imp_concl t) :: strip_imp_prems t;
|
paulson@2854
|
514 |
|
paulson@2854
|
515 |
fun convertIntrRule vars t =
|
paulson@2854
|
516 |
let val Ps = strip_imp_prems t
|
paulson@2854
|
517 |
val P = strip_imp_concl t
|
paulson@2854
|
518 |
in (mkGoal P, map (convertIntrPrem o skoPrem vars) Ps)
|
paulson@2854
|
519 |
end;
|
paulson@2854
|
520 |
|
paulson@5343
|
521 |
(*Tableau rule from introduction rule.
|
paulson@5343
|
522 |
Flag "upd" says that the inference updated the branch.
|
paulson@5343
|
523 |
Flag "dup" requests duplication of the affected formula.
|
paulson@5343
|
524 |
Since haz rules are now delayed, "dup" is always FALSE for
|
paulson@5343
|
525 |
introduction rules.*)
|
paulson@2854
|
526 |
fun fromIntrRule vars rl =
|
paulson@4065
|
527 |
let val trl = rl |> rep_thm |> #prop |> fromTerm |> convertIntrRule vars
|
paulson@5343
|
528 |
fun tac (upd,dup,rot) i =
|
paulson@5343
|
529 |
rmtac upd (if dup then Data.dup_intr rl else rl) i
|
paulson@4391
|
530 |
THEN
|
paulson@4391
|
531 |
rot_subgoals_tac (rot, #2 trl) i
|
paulson@2854
|
532 |
in (trl, tac) end;
|
paulson@2854
|
533 |
|
paulson@2854
|
534 |
|
paulson@3030
|
535 |
val dummyVar = Term.Var (("etc",0), dummyT);
|
paulson@2854
|
536 |
|
paulson@2854
|
537 |
(*Convert from prototerms to ordinary terms with dummy types
|
paulson@2924
|
538 |
Ignore abstractions; identify all Vars; STOP at given depth*)
|
paulson@2924
|
539 |
fun toTerm 0 _ = dummyVar
|
paulson@2924
|
540 |
| toTerm d (Const a) = Term.Const (a,dummyT)
|
paulson@4065
|
541 |
| toTerm d (TConst(a,_)) = Term.Const (a,dummyT) (*no need to convert type*)
|
paulson@2924
|
542 |
| toTerm d (Skolem(a,_)) = Term.Const (a,dummyT)
|
paulson@2924
|
543 |
| toTerm d (Free a) = Term.Free (a,dummyT)
|
paulson@2924
|
544 |
| toTerm d (Bound i) = Term.Bound i
|
paulson@2924
|
545 |
| toTerm d (Var _) = dummyVar
|
paulson@2924
|
546 |
| toTerm d (Abs(a,_)) = dummyVar
|
paulson@2924
|
547 |
| toTerm d (f $ u) = Term.$ (toTerm d f, toTerm (d-1) u);
|
paulson@2854
|
548 |
|
paulson@2854
|
549 |
|
paulson@2854
|
550 |
fun netMkRules P vars (nps: netpair list) =
|
paulson@2854
|
551 |
case P of
|
paulson@2854
|
552 |
(Const "*Goal*" $ G) =>
|
paulson@2924
|
553 |
let val pG = mk_tprop (toTerm 2 G)
|
paulson@2854
|
554 |
val intrs = List.concat
|
paulson@2854
|
555 |
(map (fn (inet,_) => Net.unify_term inet pG)
|
paulson@2854
|
556 |
nps)
|
paulson@2854
|
557 |
in map (fromIntrRule vars o #2) (orderlist intrs) end
|
paulson@2854
|
558 |
| _ =>
|
paulson@2924
|
559 |
let val pP = mk_tprop (toTerm 3 P)
|
paulson@2854
|
560 |
val elims = List.concat
|
paulson@2854
|
561 |
(map (fn (_,enet) => Net.unify_term enet pP)
|
paulson@2854
|
562 |
nps)
|
paulson@2854
|
563 |
in List.mapPartial (fromRule vars o #2) (orderlist elims) end;
|
paulson@2854
|
564 |
|
paulson@2854
|
565 |
(**
|
paulson@2854
|
566 |
end;
|
paulson@2854
|
567 |
**)
|
paulson@2854
|
568 |
|
paulson@3092
|
569 |
|
paulson@3092
|
570 |
(*Pending formulae carry md (may duplicate) flags*)
|
paulson@5463
|
571 |
type branch =
|
paulson@5463
|
572 |
{pairs: ((term*bool) list * (*safe formulae on this level*)
|
paulson@5463
|
573 |
(term*bool) list) list, (*haz formulae on this level*)
|
paulson@5463
|
574 |
lits: term list, (*literals: irreducible formulae*)
|
paulson@5463
|
575 |
vars: term option ref list, (*variables occurring in branch*)
|
paulson@5463
|
576 |
lim: int}; (*resource limit*)
|
paulson@3092
|
577 |
|
paulson@3092
|
578 |
val fullTrace = ref[] : branch list list ref;
|
paulson@3092
|
579 |
|
paulson@3092
|
580 |
(*Normalize a branch--for tracing*)
|
paulson@3092
|
581 |
fun norm2 (G,md) = (norm G, md);
|
paulson@3092
|
582 |
|
paulson@3092
|
583 |
fun normLev (Gs,Hs) = (map norm2 Gs, map norm2 Hs);
|
paulson@3092
|
584 |
|
paulson@5463
|
585 |
fun normBr {pairs, lits, vars, lim} =
|
paulson@5463
|
586 |
{pairs = map normLev pairs,
|
paulson@5463
|
587 |
lits = map norm lits,
|
paulson@5463
|
588 |
vars = vars,
|
paulson@5463
|
589 |
lim = lim};
|
paulson@3092
|
590 |
|
paulson@3092
|
591 |
|
paulson@4065
|
592 |
val dummyTVar = Term.TVar(("a",0), []);
|
paulson@3092
|
593 |
val dummyVar2 = Term.Var(("var",0), dummyT);
|
paulson@3092
|
594 |
|
paulson@4065
|
595 |
(*convert Blast_tac's type representation to real types for tracing*)
|
paulson@4065
|
596 |
fun showType (Free a) = Term.TFree (a,[])
|
paulson@4065
|
597 |
| showType (Var _) = dummyTVar
|
paulson@4065
|
598 |
| showType t =
|
paulson@4065
|
599 |
(case strip_comb t of
|
paulson@4065
|
600 |
(Const a, us) => Term.Type(a, map showType us)
|
paulson@4065
|
601 |
| _ => dummyT);
|
paulson@4065
|
602 |
|
paulson@4065
|
603 |
(*Display top-level overloading if any*)
|
paulson@4065
|
604 |
fun topType (TConst(a,t)) = Some (showType t)
|
paulson@4065
|
605 |
| topType (Abs(a,t)) = topType t
|
paulson@4065
|
606 |
| topType (f $ u) = (case topType f of
|
paulson@4065
|
607 |
None => topType u
|
paulson@4065
|
608 |
| some => some)
|
paulson@4065
|
609 |
| topType _ = None;
|
paulson@4065
|
610 |
|
paulson@4065
|
611 |
|
paulson@3092
|
612 |
(*Convert from prototerms to ordinary terms with dummy types for tracing*)
|
paulson@3092
|
613 |
fun showTerm d (Const a) = Term.Const (a,dummyT)
|
paulson@4065
|
614 |
| showTerm d (TConst(a,_)) = Term.Const (a,dummyT)
|
paulson@3092
|
615 |
| showTerm d (Skolem(a,_)) = Term.Const (a,dummyT)
|
paulson@3092
|
616 |
| showTerm d (Free a) = Term.Free (a,dummyT)
|
paulson@3092
|
617 |
| showTerm d (Bound i) = Term.Bound i
|
paulson@3101
|
618 |
| showTerm d (Var(ref(Some u))) = showTerm d u
|
paulson@3101
|
619 |
| showTerm d (Var(ref None)) = dummyVar2
|
paulson@3092
|
620 |
| showTerm d (Abs(a,t)) = if d=0 then dummyVar
|
paulson@3092
|
621 |
else Term.Abs(a, dummyT, showTerm (d-1) t)
|
paulson@3092
|
622 |
| showTerm d (f $ u) = if d=0 then dummyVar
|
paulson@3092
|
623 |
else Term.$ (showTerm d f, showTerm (d-1) u);
|
paulson@3092
|
624 |
|
paulson@4065
|
625 |
fun string_of sign d t = Sign.string_of_term sign (showTerm d t);
|
paulson@3092
|
626 |
|
paulson@4065
|
627 |
fun traceTerm sign t =
|
paulson@4065
|
628 |
let val t' = norm t
|
paulson@4065
|
629 |
val stm = string_of sign 8 t'
|
paulson@4065
|
630 |
in
|
paulson@4065
|
631 |
case topType t' of
|
paulson@4065
|
632 |
None => stm (*no type to attach*)
|
paulson@4065
|
633 |
| Some T => stm ^ "\t:: " ^ Sign.string_of_typ sign T
|
paulson@4065
|
634 |
end;
|
paulson@3092
|
635 |
|
paulson@3092
|
636 |
|
wenzelm@5961
|
637 |
val prs = std_output;
|
wenzelm@5961
|
638 |
|
paulson@3092
|
639 |
(*Print tracing information at each iteration of prover*)
|
paulson@3092
|
640 |
fun tracing sign brs =
|
paulson@3092
|
641 |
let fun printPairs (((G,_)::_,_)::_) = prs(traceTerm sign G)
|
paulson@3092
|
642 |
| printPairs (([],(H,_)::_)::_) = prs(traceTerm sign H ^ "\t (Unsafe)")
|
paulson@3092
|
643 |
| printPairs _ = ()
|
paulson@5463
|
644 |
fun printBrs (brs0 as {pairs, lits, lim, ...} :: brs) =
|
paulson@3092
|
645 |
(fullTrace := brs0 :: !fullTrace;
|
paulson@3092
|
646 |
seq (fn _ => prs "+") brs;
|
paulson@3092
|
647 |
prs (" [" ^ Int.toString lim ^ "] ");
|
paulson@3092
|
648 |
printPairs pairs;
|
paulson@3092
|
649 |
writeln"")
|
paulson@3092
|
650 |
in if !trace then printBrs (map normBr brs) else ()
|
paulson@3092
|
651 |
end;
|
paulson@3092
|
652 |
|
paulson@5343
|
653 |
fun traceMsg s = if !trace then writeln s else ();
|
paulson@4065
|
654 |
|
paulson@3092
|
655 |
(*Tracing: variables updated in the last branch operation?*)
|
paulson@4065
|
656 |
fun traceVars sign ntrl =
|
paulson@4065
|
657 |
if !trace then
|
paulson@4065
|
658 |
(case !ntrail-ntrl of
|
paulson@4065
|
659 |
0 => ()
|
paulson@4065
|
660 |
| 1 => prs"\t1 variable UPDATED:"
|
paulson@4065
|
661 |
| n => prs("\t" ^ Int.toString n ^ " variables UPDATED:");
|
paulson@4065
|
662 |
(*display the instantiations themselves, though no variable names*)
|
paulson@4065
|
663 |
seq (fn v => prs(" " ^ string_of sign 4 (the (!v))))
|
paulson@4065
|
664 |
(List.take(!trail, !ntrail-ntrl));
|
paulson@4065
|
665 |
writeln"")
|
paulson@3092
|
666 |
else ();
|
paulson@3092
|
667 |
|
paulson@3092
|
668 |
(*Tracing: how many new branches are created?*)
|
paulson@3092
|
669 |
fun traceNew prems =
|
paulson@3092
|
670 |
if !trace then
|
paulson@3092
|
671 |
case length prems of
|
paulson@3092
|
672 |
0 => prs"branch closed by rule"
|
paulson@3092
|
673 |
| 1 => prs"branch extended (1 new subgoal)"
|
paulson@3092
|
674 |
| n => prs("branch split: "^ Int.toString n ^ " new subgoals")
|
paulson@3092
|
675 |
else ();
|
paulson@3092
|
676 |
|
paulson@3092
|
677 |
|
paulson@3092
|
678 |
|
paulson@2854
|
679 |
(*** Code for handling equality: naive substitution, like hyp_subst_tac ***)
|
paulson@2854
|
680 |
|
paulson@2854
|
681 |
(*Replace the ATOMIC term "old" by "new" in t*)
|
paulson@2854
|
682 |
fun subst_atomic (old,new) t =
|
paulson@2854
|
683 |
let fun subst (Var(ref(Some u))) = subst u
|
paulson@2854
|
684 |
| subst (Abs(a,body)) = Abs(a, subst body)
|
paulson@2854
|
685 |
| subst (f$t) = subst f $ subst t
|
paulson@2854
|
686 |
| subst t = if t aconv old then new else t
|
paulson@2854
|
687 |
in subst t end;
|
paulson@2854
|
688 |
|
paulson@2854
|
689 |
(*Eta-contract a term from outside: just enough to reduce it to an atom*)
|
paulson@2854
|
690 |
fun eta_contract_atom (t0 as Abs(a, body)) =
|
paulson@2854
|
691 |
(case eta_contract2 body of
|
paulson@2854
|
692 |
f $ Bound 0 => if (0 mem_int loose_bnos f) then t0
|
paulson@2854
|
693 |
else eta_contract_atom (incr_boundvars ~1 f)
|
paulson@2854
|
694 |
| _ => t0)
|
paulson@2854
|
695 |
| eta_contract_atom t = t
|
paulson@2854
|
696 |
and eta_contract2 (f$t) = f $ eta_contract_atom t
|
paulson@2854
|
697 |
| eta_contract2 t = eta_contract_atom t;
|
paulson@2854
|
698 |
|
paulson@2854
|
699 |
|
paulson@2854
|
700 |
(*When can we safely delete the equality?
|
paulson@2854
|
701 |
Not if it equates two constants; consider 0=1.
|
paulson@2854
|
702 |
Not if it resembles x=t[x], since substitution does not eliminate x.
|
paulson@2854
|
703 |
Not if it resembles ?x=0; another goal could instantiate ?x to Suc(i)
|
paulson@2854
|
704 |
Prefer to eliminate Bound variables if possible.
|
paulson@2854
|
705 |
Result: true = use as is, false = reorient first *)
|
paulson@2854
|
706 |
|
paulson@4354
|
707 |
(*Can t occur in u? For substitution.
|
paulson@4354
|
708 |
Does NOT examine the args of Skolem terms: substitution does not affect them.
|
paulson@4196
|
709 |
REFLEXIVE because hyp_subst_tac fails on x=x.*)
|
paulson@2854
|
710 |
fun substOccur t =
|
paulson@4354
|
711 |
let (*NO vars are permitted in u except the arguments of t, if it is
|
paulson@4354
|
712 |
a Skolem term. This ensures that no equations are deleted that could
|
paulson@4354
|
713 |
be instantiated to a cycle. For example, x=?a is rejected because ?a
|
paulson@4354
|
714 |
could be instantiated to Suc(x).*)
|
paulson@4354
|
715 |
val vars = case t of
|
paulson@4354
|
716 |
Skolem(_,vars) => vars
|
paulson@4354
|
717 |
| _ => []
|
paulson@4354
|
718 |
fun occEq u = (t aconv u) orelse occ u
|
paulson@4354
|
719 |
and occ (Var(ref(Some u))) = occEq u
|
paulson@4354
|
720 |
| occ (Var v) = not (mem_var (v, vars))
|
paulson@4354
|
721 |
| occ (Abs(_,u)) = occEq u
|
paulson@2854
|
722 |
| occ (f$u) = occEq u orelse occEq f
|
paulson@2854
|
723 |
| occ (_) = false;
|
paulson@2854
|
724 |
in occEq end;
|
paulson@2854
|
725 |
|
paulson@3092
|
726 |
exception DEST_EQ;
|
paulson@3092
|
727 |
|
paulson@3092
|
728 |
(*Take apart an equality (plain or overloaded). NO constant Trueprop*)
|
paulson@3092
|
729 |
fun dest_eq (Const "op =" $ t $ u) =
|
paulson@3092
|
730 |
(eta_contract_atom t, eta_contract_atom u)
|
paulson@4065
|
731 |
| dest_eq (TConst("op =",_) $ t $ u) =
|
paulson@3092
|
732 |
(eta_contract_atom t, eta_contract_atom u)
|
paulson@3092
|
733 |
| dest_eq _ = raise DEST_EQ;
|
paulson@3092
|
734 |
|
paulson@4196
|
735 |
(*Reject the equality if u occurs in (or equals!) t*)
|
paulson@2854
|
736 |
fun check (t,u,v) = if substOccur t u then raise DEST_EQ else v;
|
paulson@2854
|
737 |
|
paulson@2854
|
738 |
(*IF the goal is an equality with a substitutable variable
|
paulson@2854
|
739 |
THEN orient that equality ELSE raise exception DEST_EQ*)
|
paulson@3092
|
740 |
fun orientGoal (t,u) = case (t,u) of
|
paulson@2854
|
741 |
(Skolem _, _) => check(t,u,(t,u)) (*eliminates t*)
|
paulson@2854
|
742 |
| (_, Skolem _) => check(u,t,(u,t)) (*eliminates u*)
|
paulson@2854
|
743 |
| (Free _, _) => check(t,u,(t,u)) (*eliminates t*)
|
paulson@2854
|
744 |
| (_, Free _) => check(u,t,(u,t)) (*eliminates u*)
|
paulson@2854
|
745 |
| _ => raise DEST_EQ;
|
paulson@2854
|
746 |
|
paulson@2894
|
747 |
(*Substitute through the branch if an equality goal (else raise DEST_EQ).
|
paulson@2894
|
748 |
Moves affected literals back into the branch, but it is not clear where
|
paulson@4391
|
749 |
they should go: this could make proofs fail.*)
|
paulson@5463
|
750 |
fun equalSubst sign (G, {pairs, lits, vars, lim}) =
|
paulson@3092
|
751 |
let val (t,u) = orientGoal(dest_eq G)
|
paulson@3092
|
752 |
val subst = subst_atomic (t,u)
|
paulson@2854
|
753 |
fun subst2(G,md) = (subst G, md)
|
paulson@4466
|
754 |
(*substitute throughout list; extract affected formulae*)
|
paulson@4466
|
755 |
fun subForm ((G,md), (changed, pairs)) =
|
paulson@4466
|
756 |
let val nG = subst G
|
paulson@4466
|
757 |
in if nG aconv G then (changed, (G,md)::pairs)
|
paulson@4466
|
758 |
else ((nG,md)::changed, pairs)
|
paulson@2924
|
759 |
end
|
paulson@4466
|
760 |
(*substitute throughout "stack frame"; extract affected formulae*)
|
paulson@4466
|
761 |
fun subFrame ((Gs,Hs), (changed, frames)) =
|
paulson@4466
|
762 |
let val (changed', Gs') = foldr subForm (Gs, (changed, []))
|
paulson@4466
|
763 |
val (changed'', Hs') = foldr subForm (Hs, (changed', []))
|
paulson@4466
|
764 |
in (changed'', (Gs',Hs')::frames) end
|
paulson@4466
|
765 |
(*substitute throughout literals; extract affected ones*)
|
paulson@4466
|
766 |
fun subLit (lit, (changed, nlits)) =
|
paulson@2854
|
767 |
let val nlit = subst lit
|
paulson@4466
|
768 |
in if nlit aconv lit then (changed, nlit::nlits)
|
paulson@4466
|
769 |
else ((nlit,true)::changed, nlits)
|
paulson@2854
|
770 |
end
|
paulson@4466
|
771 |
val (changed, lits') = foldr subLit (lits, ([], []))
|
paulson@4466
|
772 |
val (changed', pairs') = foldr subFrame (pairs, (changed, []))
|
paulson@3092
|
773 |
in if !trace then writeln ("Substituting " ^ traceTerm sign u ^
|
paulson@3092
|
774 |
" for " ^ traceTerm sign t ^ " in branch" )
|
paulson@3092
|
775 |
else ();
|
paulson@5463
|
776 |
{pairs = (changed',[])::pairs', (*affected formulas, and others*)
|
paulson@5463
|
777 |
lits = lits', (*unaffected literals*)
|
paulson@5463
|
778 |
vars = vars,
|
paulson@5463
|
779 |
lim = lim}
|
paulson@2854
|
780 |
end;
|
paulson@2854
|
781 |
|
paulson@2854
|
782 |
|
paulson@2854
|
783 |
exception NEWBRANCHES and CLOSEF;
|
paulson@2854
|
784 |
|
paulson@2854
|
785 |
exception PROVE;
|
paulson@2854
|
786 |
|
paulson@4391
|
787 |
(*Trying eq_contr_tac first INCREASES the effort, slowing reconstruction*)
|
paulson@4391
|
788 |
val contr_tac = ematch_tac [Data.notE] THEN'
|
paulson@4391
|
789 |
(eq_assume_tac ORELSE' assume_tac);
|
paulson@2854
|
790 |
|
paulson@4391
|
791 |
val eContr_tac = TRACE Data.notE contr_tac;
|
paulson@2854
|
792 |
val eAssume_tac = TRACE asm_rl (eq_assume_tac ORELSE' assume_tac);
|
paulson@2854
|
793 |
|
paulson@2854
|
794 |
(*Try to unify complementary literals and return the corresponding tactic. *)
|
paulson@3083
|
795 |
fun tryClose (Const"*Goal*" $ G, L) =
|
paulson@4065
|
796 |
if unify([],G,L) then Some eAssume_tac else None
|
paulson@3083
|
797 |
| tryClose (G, Const"*Goal*" $ L) =
|
paulson@4065
|
798 |
if unify([],G,L) then Some eAssume_tac else None
|
paulson@3083
|
799 |
| tryClose (Const"Not" $ G, L) =
|
paulson@4065
|
800 |
if unify([],G,L) then Some eContr_tac else None
|
paulson@3083
|
801 |
| tryClose (G, Const"Not" $ L) =
|
paulson@4065
|
802 |
if unify([],G,L) then Some eContr_tac else None
|
paulson@3083
|
803 |
| tryClose _ = None;
|
paulson@2854
|
804 |
|
paulson@2854
|
805 |
|
paulson@2854
|
806 |
(*Were there Skolem terms in the premise? Must NOT chase Vars*)
|
paulson@2854
|
807 |
fun hasSkolem (Skolem _) = true
|
paulson@2854
|
808 |
| hasSkolem (Abs (_,body)) = hasSkolem body
|
paulson@2854
|
809 |
| hasSkolem (f$t) = hasSkolem f orelse hasSkolem t
|
paulson@2854
|
810 |
| hasSkolem _ = false;
|
paulson@2854
|
811 |
|
paulson@2854
|
812 |
(*Attach the right "may duplicate" flag to new formulae: if they contain
|
paulson@2854
|
813 |
Skolem terms then allow duplication.*)
|
paulson@2854
|
814 |
fun joinMd md [] = []
|
paulson@2854
|
815 |
| joinMd md (G::Gs) = (G, hasSkolem G orelse md) :: joinMd md Gs;
|
paulson@2854
|
816 |
|
paulson@2894
|
817 |
(*Convert a Goal to an ordinary Not. Used also in dup_intr, where a goal like
|
paulson@2894
|
818 |
Ex(P) is duplicated as the assumption ~Ex(P). *)
|
paulson@2894
|
819 |
fun negOfGoal (Const"*Goal*" $ G) = negate G
|
paulson@2894
|
820 |
| negOfGoal G = G;
|
paulson@2894
|
821 |
|
paulson@2894
|
822 |
fun negOfGoal2 (G,md) = (negOfGoal G, md);
|
paulson@2894
|
823 |
|
paulson@2894
|
824 |
(*Converts all Goals to Nots in the safe parts of a branch. They could
|
paulson@2894
|
825 |
have been moved there from the literals list after substitution (equalSubst).
|
paulson@2894
|
826 |
There can be at most one--this function could be made more efficient.*)
|
paulson@2894
|
827 |
fun negOfGoals pairs = map (fn (Gs,haz) => (map negOfGoal2 Gs, haz)) pairs;
|
paulson@2894
|
828 |
|
paulson@2894
|
829 |
(*Tactic. Convert *Goal* to negated assumption in FIRST position*)
|
paulson@4391
|
830 |
fun negOfGoal_tac i = TRACE Data.ccontr (rtac Data.ccontr) i THEN
|
paulson@4391
|
831 |
rotate_tac ~1 i;
|
paulson@2894
|
832 |
|
paulson@2854
|
833 |
|
paulson@2854
|
834 |
(** Backtracking and Pruning **)
|
paulson@2854
|
835 |
|
paulson@2854
|
836 |
(*clashVar vars (n,trail) determines whether any of the last n elements
|
paulson@2854
|
837 |
of "trail" occur in "vars" OR in their instantiations*)
|
paulson@2854
|
838 |
fun clashVar [] = (fn _ => false)
|
paulson@2854
|
839 |
| clashVar vars =
|
paulson@2854
|
840 |
let fun clash (0, _) = false
|
paulson@2854
|
841 |
| clash (_, []) = false
|
paulson@2854
|
842 |
| clash (n, v::vs) = exists (varOccur v) vars orelse clash(n-1,vs)
|
paulson@2854
|
843 |
in clash end;
|
paulson@2854
|
844 |
|
paulson@2854
|
845 |
|
paulson@2854
|
846 |
(*nbrs = # of branches just prior to closing this one. Delete choice points
|
paulson@2854
|
847 |
for goals proved by the latest inference, provided NO variables in the
|
paulson@2854
|
848 |
next branch have been updated.*)
|
paulson@2854
|
849 |
fun prune (1, nxtVars, choices) = choices (*DON'T prune at very end: allow
|
paulson@2854
|
850 |
backtracking over bad proofs*)
|
paulson@2854
|
851 |
| prune (nbrs, nxtVars, choices) =
|
paulson@2854
|
852 |
let fun traceIt last =
|
paulson@2854
|
853 |
let val ll = length last
|
paulson@2854
|
854 |
and lc = length choices
|
paulson@2854
|
855 |
in if !trace andalso ll<lc then
|
paulson@3083
|
856 |
(writeln("Pruning " ^ Int.toString(lc-ll) ^ " levels");
|
paulson@2854
|
857 |
last)
|
paulson@2854
|
858 |
else last
|
paulson@2854
|
859 |
end
|
paulson@2854
|
860 |
fun pruneAux (last, _, _, []) = last
|
paulson@3083
|
861 |
| pruneAux (last, ntrl, trl, (ntrl',nbrs',exn) :: choices) =
|
paulson@2854
|
862 |
if nbrs' < nbrs
|
paulson@2854
|
863 |
then last (*don't backtrack beyond first solution of goal*)
|
paulson@2854
|
864 |
else if nbrs' > nbrs then pruneAux (last, ntrl, trl, choices)
|
paulson@2854
|
865 |
else (* nbrs'=nbrs *)
|
paulson@2854
|
866 |
if clashVar nxtVars (ntrl-ntrl', trl) then last
|
paulson@2854
|
867 |
else (*no clashes: can go back at least this far!*)
|
paulson@2854
|
868 |
pruneAux(choices, ntrl', List.drop(trl, ntrl-ntrl'),
|
paulson@2854
|
869 |
choices)
|
paulson@2854
|
870 |
in traceIt (pruneAux (choices, !ntrail, !trail, choices)) end;
|
paulson@2854
|
871 |
|
paulson@5463
|
872 |
fun nextVars ({pairs, lits, vars, lim} :: _) = map Var vars
|
paulson@5463
|
873 |
| nextVars [] = [];
|
paulson@2854
|
874 |
|
paulson@3083
|
875 |
fun backtrack (choices as (ntrl, nbrs, exn)::_) =
|
paulson@3083
|
876 |
(if !trace then (writeln ("Backtracking; now there are " ^
|
paulson@3083
|
877 |
Int.toString nbrs ^ " branches"))
|
paulson@3083
|
878 |
else ();
|
paulson@3083
|
879 |
raise exn)
|
paulson@3083
|
880 |
| backtrack _ = raise PROVE;
|
paulson@2854
|
881 |
|
paulson@2894
|
882 |
(*Add the literal G, handling *Goal* and detecting duplicates.*)
|
paulson@2894
|
883 |
fun addLit (Const "*Goal*" $ G, lits) =
|
paulson@2894
|
884 |
(*New literal is a *Goal*, so change all other Goals to Nots*)
|
paulson@2854
|
885 |
let fun bad (Const"*Goal*" $ _) = true
|
paulson@2854
|
886 |
| bad (Const"Not" $ G') = G aconv G'
|
paulson@2854
|
887 |
| bad _ = false;
|
paulson@2854
|
888 |
fun change [] = []
|
paulson@2854
|
889 |
| change (Const"*Goal*" $ G' :: lits) =
|
paulson@2854
|
890 |
if G aconv G' then change lits
|
paulson@2854
|
891 |
else Const"Not" $ G' :: change lits
|
paulson@2854
|
892 |
| change (Const"Not" $ G' :: lits) =
|
paulson@2854
|
893 |
if G aconv G' then change lits
|
paulson@2854
|
894 |
else Const"Not" $ G' :: change lits
|
paulson@2854
|
895 |
| change (lit::lits) = lit :: change lits
|
paulson@2854
|
896 |
in
|
paulson@2854
|
897 |
Const "*Goal*" $ G :: (if exists bad lits then change lits else lits)
|
paulson@2854
|
898 |
end
|
paulson@2854
|
899 |
| addLit (G,lits) = ins_term(G, lits)
|
paulson@2854
|
900 |
|
paulson@2854
|
901 |
|
paulson@2952
|
902 |
(*For calculating the "penalty" to assess on a branching factor of n
|
paulson@2952
|
903 |
log2 seems a little too severe*)
|
paulson@3083
|
904 |
fun log n = if n<4 then 0 else 1 + log(n div 4);
|
paulson@2924
|
905 |
|
paulson@2924
|
906 |
|
paulson@3021
|
907 |
(*match(t,u) says whether the term u might be an instance of the pattern t
|
paulson@3021
|
908 |
Used to detect "recursive" rules such as transitivity*)
|
paulson@3021
|
909 |
fun match (Var _) u = true
|
paulson@4065
|
910 |
| match (Const"*Goal*") (Const"Not") = true
|
paulson@4065
|
911 |
| match (Const"Not") (Const"*Goal*") = true
|
paulson@4065
|
912 |
| match (Const a) (Const b) = (a=b)
|
paulson@4065
|
913 |
| match (TConst (a,ta)) (TConst (b,tb)) = a=b andalso match ta tb
|
paulson@4065
|
914 |
| match (Free a) (Free b) = (a=b)
|
paulson@4065
|
915 |
| match (Bound i) (Bound j) = (i=j)
|
paulson@4065
|
916 |
| match (Abs(_,t)) (Abs(_,u)) = match t u
|
paulson@4065
|
917 |
| match (f$t) (g$u) = match f g andalso match t u
|
paulson@4065
|
918 |
| match t u = false;
|
paulson@3021
|
919 |
|
paulson@3021
|
920 |
|
paulson@4300
|
921 |
(*Branches closed: number of branches closed during the search
|
paulson@4300
|
922 |
Branches tried: number of branches created by splitting (counting from 1)*)
|
paulson@4300
|
923 |
val nclosed = ref 0
|
paulson@4300
|
924 |
and ntried = ref 1;
|
paulson@4300
|
925 |
|
paulson@4391
|
926 |
fun printStats (b, start, tacs) =
|
paulson@4323
|
927 |
if b then
|
paulson@4323
|
928 |
writeln (endTiming start ^ " for search. Closed: "
|
paulson@4323
|
929 |
^ Int.toString (!nclosed) ^
|
paulson@4391
|
930 |
" tried: " ^ Int.toString (!ntried) ^
|
paulson@4391
|
931 |
" tactics: " ^ Int.toString (length tacs))
|
paulson@4323
|
932 |
else ();
|
paulson@4323
|
933 |
|
paulson@4323
|
934 |
|
paulson@2854
|
935 |
(*Tableau prover based on leanTaP. Argument is a list of branches. Each
|
paulson@2854
|
936 |
branch contains a list of unexpanded formulae, a list of literals, and a
|
paulson@4391
|
937 |
bound on unsafe expansions.
|
paulson@4391
|
938 |
"start" is CPU time at start, for printing search time
|
paulson@4391
|
939 |
*)
|
paulson@4391
|
940 |
fun prove (sign, start, cs, brs, cont) =
|
oheimb@4653
|
941 |
let val {safe0_netpair, safep_netpair, haz_netpair, ...} = Data.rep_cs cs
|
paulson@2854
|
942 |
val safeList = [safe0_netpair, safep_netpair]
|
paulson@2854
|
943 |
and hazList = [haz_netpair]
|
paulson@4065
|
944 |
fun prv (tacs, trs, choices, []) =
|
paulson@4391
|
945 |
(printStats (!trace orelse !stats, start, tacs);
|
paulson@4323
|
946 |
cont (tacs, trs, choices)) (*all branches closed!*)
|
paulson@2854
|
947 |
| prv (tacs, trs, choices,
|
paulson@5463
|
948 |
brs0 as {pairs = ((G,md)::br, haz)::pairs,
|
paulson@5463
|
949 |
lits, vars, lim} :: brs) =
|
paulson@3917
|
950 |
(*apply a safe rule only (possibly allowing instantiation);
|
paulson@3917
|
951 |
defer any haz formulae*)
|
paulson@2854
|
952 |
let exception PRV (*backtrack to precisely this recursion!*)
|
paulson@2854
|
953 |
val ntrl = !ntrail
|
paulson@2854
|
954 |
val nbrs = length brs0
|
paulson@2854
|
955 |
val nxtVars = nextVars brs
|
paulson@2854
|
956 |
val G = norm G
|
paulson@2924
|
957 |
val rules = netMkRules G vars safeList
|
paulson@2854
|
958 |
(*Make a new branch, decrementing "lim" if instantiations occur*)
|
paulson@2894
|
959 |
fun newBr (vars',lim') prems =
|
paulson@2894
|
960 |
map (fn prem =>
|
paulson@2894
|
961 |
if (exists isGoal prem)
|
paulson@5463
|
962 |
then {pairs = ((joinMd md prem, []) ::
|
paulson@5463
|
963 |
negOfGoals ((br, haz)::pairs)),
|
paulson@5463
|
964 |
lits = map negOfGoal lits,
|
paulson@5463
|
965 |
vars = vars',
|
paulson@5463
|
966 |
lim = lim'}
|
paulson@5463
|
967 |
else {pairs = ((joinMd md prem, []) ::
|
paulson@5463
|
968 |
(br, haz) :: pairs),
|
paulson@5463
|
969 |
lits = lits,
|
paulson@5463
|
970 |
vars = vars',
|
paulson@5463
|
971 |
lim = lim'})
|
paulson@2854
|
972 |
prems @
|
paulson@2854
|
973 |
brs
|
paulson@2854
|
974 |
(*Seek a matching rule. If unifiable then add new premises
|
paulson@2854
|
975 |
to branch.*)
|
paulson@2854
|
976 |
fun deeper [] = raise NEWBRANCHES
|
paulson@2854
|
977 |
| deeper (((P,prems),tac)::grls) =
|
paulson@4065
|
978 |
if unify(add_term_vars(P,[]), P, G)
|
paulson@3083
|
979 |
then (*P comes from the rule; G comes from the branch.*)
|
paulson@5343
|
980 |
let val updated = ntrl < !ntrail (*branch updated*)
|
paulson@5343
|
981 |
val lim' = if updated
|
paulson@3083
|
982 |
then lim - (1+log(length rules))
|
paulson@3083
|
983 |
else lim (*discourage branching updates*)
|
paulson@3083
|
984 |
val vars = vars_in_vars vars
|
paulson@3083
|
985 |
val vars' = foldr add_terms_vars (prems, vars)
|
paulson@3083
|
986 |
val choices' = (ntrl, nbrs, PRV) :: choices
|
paulson@5463
|
987 |
val tacs' = (tac(updated,false,true))
|
paulson@5343
|
988 |
:: tacs (*no duplication; rotate*)
|
paulson@3083
|
989 |
in
|
paulson@4065
|
990 |
traceNew prems; traceVars sign ntrl;
|
paulson@3083
|
991 |
(if null prems then (*closed the branch: prune!*)
|
paulson@4300
|
992 |
(nclosed := !nclosed + 1;
|
paulson@4300
|
993 |
prv(tacs', brs0::trs,
|
paulson@4300
|
994 |
prune (nbrs, nxtVars, choices'),
|
paulson@4300
|
995 |
brs))
|
paulson@4300
|
996 |
else (*prems non-null*)
|
paulson@3083
|
997 |
if lim'<0 (*faster to kill ALL the alternatives*)
|
paulson@5343
|
998 |
then (traceMsg"Excessive branching: KILLED";
|
paulson@4065
|
999 |
clearTo ntrl; raise NEWBRANCHES)
|
paulson@3083
|
1000 |
else
|
paulson@4300
|
1001 |
(ntried := !ntried + length prems - 1;
|
paulson@4300
|
1002 |
prv(tacs', brs0::trs, choices',
|
paulson@4300
|
1003 |
newBr (vars',lim') prems)))
|
paulson@3083
|
1004 |
handle PRV =>
|
paulson@5343
|
1005 |
if updated then
|
paulson@3083
|
1006 |
(*Backtrack at this level.
|
paulson@3083
|
1007 |
Reset Vars and try another rule*)
|
paulson@3083
|
1008 |
(clearTo ntrl; deeper grls)
|
paulson@3083
|
1009 |
else (*backtrack to previous level*)
|
paulson@3083
|
1010 |
backtrack choices
|
paulson@3083
|
1011 |
end
|
paulson@3083
|
1012 |
else deeper grls
|
paulson@2854
|
1013 |
(*Try to close branch by unifying with head goal*)
|
paulson@2854
|
1014 |
fun closeF [] = raise CLOSEF
|
paulson@2854
|
1015 |
| closeF (L::Ls) =
|
paulson@3083
|
1016 |
case tryClose(G,L) of
|
paulson@3083
|
1017 |
None => closeF Ls
|
paulson@3083
|
1018 |
| Some tac =>
|
paulson@3083
|
1019 |
let val choices' =
|
paulson@3092
|
1020 |
(if !trace then (prs"branch closed";
|
paulson@4065
|
1021 |
traceVars sign ntrl)
|
paulson@3083
|
1022 |
else ();
|
paulson@3083
|
1023 |
prune (nbrs, nxtVars,
|
paulson@3083
|
1024 |
(ntrl, nbrs, PRV) :: choices))
|
paulson@4300
|
1025 |
in nclosed := !nclosed + 1;
|
paulson@4300
|
1026 |
prv (tac::tacs, brs0::trs, choices', brs)
|
paulson@3083
|
1027 |
handle PRV =>
|
paulson@3083
|
1028 |
(*reset Vars and try another literal
|
paulson@3083
|
1029 |
[this handler is pruned if possible!]*)
|
paulson@3083
|
1030 |
(clearTo ntrl; closeF Ls)
|
paulson@3083
|
1031 |
end
|
paulson@2894
|
1032 |
fun closeFl [] = raise CLOSEF
|
paulson@2894
|
1033 |
| closeFl ((br, haz)::pairs) =
|
paulson@2894
|
1034 |
closeF (map fst br)
|
paulson@2894
|
1035 |
handle CLOSEF => closeF (map fst haz)
|
paulson@2894
|
1036 |
handle CLOSEF => closeFl pairs
|
paulson@3083
|
1037 |
in tracing sign brs0;
|
paulson@4065
|
1038 |
if lim<0 then (traceMsg "Limit reached. "; backtrack choices)
|
paulson@2854
|
1039 |
else
|
paulson@4466
|
1040 |
prv (Data.hyp_subst_tac trace :: tacs,
|
paulson@2854
|
1041 |
brs0::trs, choices,
|
paulson@5463
|
1042 |
equalSubst sign
|
paulson@5463
|
1043 |
(G, {pairs = (br,haz)::pairs,
|
paulson@5463
|
1044 |
lits = lits, vars = vars, lim = lim})
|
paulson@5463
|
1045 |
:: brs)
|
paulson@4065
|
1046 |
handle DEST_EQ => closeF lits
|
paulson@4065
|
1047 |
handle CLOSEF => closeFl ((br,haz)::pairs)
|
paulson@4065
|
1048 |
handle CLOSEF => deeper rules
|
paulson@2894
|
1049 |
handle NEWBRANCHES =>
|
paulson@2894
|
1050 |
(case netMkRules G vars hazList of
|
paulson@4466
|
1051 |
[] => (*there are no plausible haz rules*)
|
paulson@5463
|
1052 |
(traceMsg "moving formula to literals";
|
paulson@5463
|
1053 |
prv (tacs, brs0::trs, choices,
|
paulson@5463
|
1054 |
{pairs = (br,haz)::pairs,
|
paulson@5463
|
1055 |
lits = addLit(G,lits),
|
paulson@5463
|
1056 |
vars = vars,
|
paulson@5463
|
1057 |
lim = lim} :: brs))
|
paulson@2894
|
1058 |
| _ => (*G admits some haz rules: try later*)
|
paulson@5463
|
1059 |
(traceMsg "moving formula to haz list";
|
paulson@4466
|
1060 |
prv (if isGoal G then negOfGoal_tac :: tacs
|
paulson@5463
|
1061 |
else tacs,
|
paulson@5463
|
1062 |
brs0::trs,
|
paulson@5463
|
1063 |
choices,
|
paulson@5463
|
1064 |
{pairs = (br, haz@[(negOfGoal G, md)])::pairs,
|
paulson@5463
|
1065 |
lits = lits,
|
paulson@5463
|
1066 |
vars = vars,
|
paulson@5463
|
1067 |
lim = lim} :: brs)))
|
paulson@2854
|
1068 |
end
|
paulson@2924
|
1069 |
| prv (tacs, trs, choices,
|
paulson@5463
|
1070 |
{pairs = ([],haz)::(Gs,haz')::pairs, lits, vars, lim} :: brs) =
|
paulson@2894
|
1071 |
(*no more "safe" formulae: transfer haz down a level*)
|
paulson@2924
|
1072 |
prv (tacs, trs, choices,
|
paulson@5463
|
1073 |
{pairs = (Gs,haz@haz')::pairs,
|
paulson@5463
|
1074 |
lits = lits,
|
paulson@5463
|
1075 |
vars = vars,
|
paulson@5463
|
1076 |
lim = lim} :: brs)
|
paulson@2854
|
1077 |
| prv (tacs, trs, choices,
|
paulson@5463
|
1078 |
brs0 as {pairs = [([], (H,md)::Hs)],
|
paulson@5463
|
1079 |
lits, vars, lim} :: brs) =
|
paulson@2894
|
1080 |
(*no safe steps possible at any level: apply a haz rule*)
|
paulson@2854
|
1081 |
let exception PRV (*backtrack to precisely this recursion!*)
|
paulson@2894
|
1082 |
val H = norm H
|
paulson@2854
|
1083 |
val ntrl = !ntrail
|
paulson@2924
|
1084 |
val rules = netMkRules H vars hazList
|
paulson@3021
|
1085 |
(*new premises of haz rules may NOT be duplicated*)
|
paulson@4391
|
1086 |
fun newPrem (vars,P,dup,lim') prem =
|
paulson@4391
|
1087 |
let val Gs' = map (fn Q => (Q,false)) prem
|
paulson@3021
|
1088 |
and Hs' = if dup then Hs @ [(negOfGoal H, md)] else Hs
|
paulson@4196
|
1089 |
and lits' = if (exists isGoal prem)
|
paulson@4196
|
1090 |
then map negOfGoal lits
|
paulson@4196
|
1091 |
else lits
|
paulson@5463
|
1092 |
in {pairs = if exists (match P) prem then [(Gs',Hs')]
|
paulson@5463
|
1093 |
(*Recursive in this premise. Don't make new
|
paulson@5463
|
1094 |
"stack frame". New haz premises will end up
|
paulson@5463
|
1095 |
at the BACK of the queue, preventing
|
paulson@5463
|
1096 |
exclusion of others*)
|
paulson@5463
|
1097 |
else [(Gs',[]), ([],Hs')],
|
paulson@5463
|
1098 |
lits = lits',
|
paulson@5463
|
1099 |
vars = vars,
|
paulson@5463
|
1100 |
lim = lim'}
|
paulson@3021
|
1101 |
end
|
paulson@2854
|
1102 |
fun newBr x prems = map (newPrem x) prems @ brs
|
paulson@2854
|
1103 |
(*Seek a matching rule. If unifiable then add new premises
|
paulson@2854
|
1104 |
to branch.*)
|
paulson@2854
|
1105 |
fun deeper [] = raise NEWBRANCHES
|
paulson@2854
|
1106 |
| deeper (((P,prems),tac)::grls) =
|
paulson@4065
|
1107 |
if unify(add_term_vars(P,[]), P, H)
|
paulson@3083
|
1108 |
then
|
paulson@5343
|
1109 |
let val updated = ntrl < !ntrail (*branch updated*)
|
paulson@3083
|
1110 |
val vars = vars_in_vars vars
|
paulson@3083
|
1111 |
val vars' = foldr add_terms_vars (prems, vars)
|
paulson@3083
|
1112 |
(*duplicate H if md and the subgoal has new vars*)
|
paulson@3083
|
1113 |
val dup = md andalso vars' <> vars
|
paulson@5463
|
1114 |
(*any instances of P in the subgoals?
|
paulson@5463
|
1115 |
NB: this boolean affects tracing only!*)
|
paulson@3083
|
1116 |
and recur = exists (exists (match P)) prems
|
paulson@3083
|
1117 |
val lim' = (*Decrement "lim" extra if updates occur*)
|
paulson@5343
|
1118 |
if updated then lim - (1+log(length rules))
|
paulson@3083
|
1119 |
else lim-1
|
paulson@3083
|
1120 |
(*It is tempting to leave "lim" UNCHANGED if
|
paulson@3083
|
1121 |
both dup and recur are false. Proofs are
|
paulson@3083
|
1122 |
found at shallower depths, but looping
|
paulson@3083
|
1123 |
occurs too often...*)
|
paulson@3917
|
1124 |
val mayUndo =
|
paulson@3917
|
1125 |
(*Allowing backtracking from a rule application
|
paulson@3917
|
1126 |
if other matching rules exist, if the rule
|
paulson@3917
|
1127 |
updated variables, or if the rule did not
|
paulson@3917
|
1128 |
introduce new variables. This latter condition
|
paulson@3917
|
1129 |
means it is not a standard "gamma-rule" but
|
paulson@3917
|
1130 |
some other form of unsafe rule. Aim is to
|
paulson@3917
|
1131 |
emulate Fast_tac, which allows all unsafe steps
|
paulson@3917
|
1132 |
to be undone.*)
|
paulson@3917
|
1133 |
not(null grls) (*other rules to try?*)
|
paulson@5343
|
1134 |
orelse updated
|
paulson@3917
|
1135 |
orelse vars=vars' (*no new Vars?*)
|
paulson@5481
|
1136 |
val tac' = tac(updated, dup, true)
|
paulson@5463
|
1137 |
(*if recur then perhaps shouldn't call rotate_tac: new
|
paulson@5463
|
1138 |
formulae should be last, but that's WRONG if the new
|
paulson@5463
|
1139 |
formulae are Goals, since they remain in the first
|
paulson@5463
|
1140 |
position*)
|
paulson@5463
|
1141 |
|
paulson@3083
|
1142 |
in
|
paulson@3083
|
1143 |
if lim'<0 andalso not (null prems)
|
paulson@3083
|
1144 |
then (*it's faster to kill ALL the alternatives*)
|
paulson@5343
|
1145 |
(traceMsg"Excessive branching: KILLED";
|
paulson@4065
|
1146 |
clearTo ntrl; raise NEWBRANCHES)
|
paulson@3083
|
1147 |
else
|
paulson@4391
|
1148 |
traceNew prems;
|
paulson@4391
|
1149 |
if !trace andalso recur then prs" (recursive)"
|
paulson@4391
|
1150 |
else ();
|
paulson@4391
|
1151 |
traceVars sign ntrl;
|
paulson@4300
|
1152 |
if null prems then nclosed := !nclosed + 1
|
paulson@4300
|
1153 |
else ntried := !ntried + length prems - 1;
|
paulson@4391
|
1154 |
prv(tac' :: tacs,
|
paulson@3083
|
1155 |
brs0::trs,
|
paulson@3083
|
1156 |
(ntrl, length brs0, PRV) :: choices,
|
paulson@4391
|
1157 |
newBr (vars', P, dup, lim') prems)
|
paulson@3083
|
1158 |
handle PRV =>
|
paulson@3083
|
1159 |
if mayUndo
|
paulson@3083
|
1160 |
then (*reset Vars and try another rule*)
|
paulson@3083
|
1161 |
(clearTo ntrl; deeper grls)
|
paulson@3083
|
1162 |
else (*backtrack to previous level*)
|
paulson@3083
|
1163 |
backtrack choices
|
paulson@3083
|
1164 |
end
|
paulson@3083
|
1165 |
else deeper grls
|
paulson@3083
|
1166 |
in tracing sign brs0;
|
paulson@4065
|
1167 |
if lim<1 then (traceMsg "Limit reached. "; backtrack choices)
|
paulson@2924
|
1168 |
else deeper rules
|
paulson@2854
|
1169 |
handle NEWBRANCHES =>
|
paulson@2894
|
1170 |
(*cannot close branch: move H to literals*)
|
paulson@2854
|
1171 |
prv (tacs, brs0::trs, choices,
|
paulson@5463
|
1172 |
{pairs = [([], Hs)],
|
paulson@5463
|
1173 |
lits = H::lits,
|
paulson@5463
|
1174 |
vars = vars,
|
paulson@5463
|
1175 |
lim = lim} :: brs)
|
paulson@2854
|
1176 |
end
|
paulson@2854
|
1177 |
| prv (tacs, trs, choices, _ :: brs) = backtrack choices
|
paulson@4065
|
1178 |
in init_gensym();
|
paulson@4065
|
1179 |
prv ([], [], [(!ntrail, length brs, PROVE)], brs)
|
paulson@4065
|
1180 |
end;
|
paulson@2854
|
1181 |
|
paulson@2854
|
1182 |
|
paulson@2883
|
1183 |
(*Construct an initial branch.*)
|
paulson@2854
|
1184 |
fun initBranch (ts,lim) =
|
paulson@5463
|
1185 |
{pairs = [(map (fn t => (t,true)) ts, [])],
|
paulson@5463
|
1186 |
lits = [],
|
paulson@5463
|
1187 |
vars = add_terms_vars (ts,[]),
|
paulson@5463
|
1188 |
lim = lim};
|
paulson@2854
|
1189 |
|
paulson@2854
|
1190 |
|
paulson@2854
|
1191 |
(*** Conversion & Skolemization of the Isabelle proof state ***)
|
paulson@2854
|
1192 |
|
paulson@2854
|
1193 |
(*Make a list of all the parameters in a subgoal, even if nested*)
|
paulson@2854
|
1194 |
local open Term
|
paulson@2854
|
1195 |
in
|
paulson@2854
|
1196 |
fun discard_foralls (Const("all",_)$Abs(a,T,t)) = discard_foralls t
|
paulson@2854
|
1197 |
| discard_foralls t = t;
|
paulson@2854
|
1198 |
end;
|
paulson@2854
|
1199 |
|
paulson@2854
|
1200 |
|
paulson@2854
|
1201 |
(*List of variables not appearing as arguments to the given parameter*)
|
paulson@2854
|
1202 |
fun getVars [] i = []
|
paulson@2854
|
1203 |
| getVars ((_,(v,is))::alist) i =
|
paulson@2854
|
1204 |
if i mem is then getVars alist i
|
paulson@2854
|
1205 |
else v :: getVars alist i;
|
paulson@2854
|
1206 |
|
paulson@4233
|
1207 |
exception TRANS of string;
|
paulson@2854
|
1208 |
|
paulson@4233
|
1209 |
(*Translation of a subgoal: Skolemize all parameters*)
|
paulson@4065
|
1210 |
fun fromSubgoal t =
|
paulson@4065
|
1211 |
let val alistVar = ref []
|
paulson@4065
|
1212 |
and alistTVar = ref []
|
paulson@2854
|
1213 |
fun hdvar ((ix,(v,is))::_) = v
|
paulson@2854
|
1214 |
fun from lev t =
|
paulson@2854
|
1215 |
let val (ht,ts) = Term.strip_comb t
|
paulson@2854
|
1216 |
fun apply u = list_comb (u, map (from lev) ts)
|
paulson@2854
|
1217 |
fun bounds [] = []
|
paulson@2854
|
1218 |
| bounds (Term.Bound i::ts) =
|
paulson@4233
|
1219 |
if i<lev then raise TRANS
|
paulson@4233
|
1220 |
"Function unknown's argument not a parameter"
|
paulson@2854
|
1221 |
else i-lev :: bounds ts
|
paulson@4233
|
1222 |
| bounds ts = raise TRANS
|
paulson@4233
|
1223 |
"Function unknown's argument not a bound variable"
|
paulson@2854
|
1224 |
in
|
paulson@2854
|
1225 |
case ht of
|
paulson@4065
|
1226 |
Term.Const aT => apply (fromConst alistTVar aT)
|
paulson@2854
|
1227 |
| Term.Free (a,_) => apply (Free a)
|
paulson@2854
|
1228 |
| Term.Bound i => apply (Bound i)
|
paulson@2854
|
1229 |
| Term.Var (ix,_) =>
|
paulson@4065
|
1230 |
(case (assoc_string_int(!alistVar,ix)) of
|
paulson@4065
|
1231 |
None => (alistVar := (ix, (ref None, bounds ts))
|
paulson@4065
|
1232 |
:: !alistVar;
|
paulson@4065
|
1233 |
Var (hdvar(!alistVar)))
|
paulson@2854
|
1234 |
| Some(v,is) => if is=bounds ts then Var v
|
paulson@4233
|
1235 |
else raise TRANS
|
paulson@5411
|
1236 |
("Discrepancy among occurrences of "
|
paulson@4233
|
1237 |
^ Syntax.string_of_vname ix))
|
paulson@2854
|
1238 |
| Term.Abs (a,_,body) =>
|
paulson@2854
|
1239 |
if null ts then Abs(a, from (lev+1) body)
|
paulson@4233
|
1240 |
else raise TRANS "argument not in normal form"
|
paulson@2854
|
1241 |
end
|
paulson@2854
|
1242 |
|
paulson@2854
|
1243 |
val npars = length (Logic.strip_params t)
|
paulson@2854
|
1244 |
|
paulson@2854
|
1245 |
(*Skolemize a subgoal from a proof state*)
|
paulson@2854
|
1246 |
fun skoSubgoal i t =
|
paulson@2854
|
1247 |
if i<npars then
|
paulson@2854
|
1248 |
skoSubgoal (i+1)
|
paulson@4065
|
1249 |
(subst_bound (Skolem (gensym "T_", getVars (!alistVar) i),
|
paulson@2854
|
1250 |
t))
|
paulson@2854
|
1251 |
else t
|
paulson@2854
|
1252 |
|
paulson@2854
|
1253 |
in skoSubgoal 0 (from 0 (discard_foralls t)) end;
|
paulson@2854
|
1254 |
|
paulson@2854
|
1255 |
|
paulson@4300
|
1256 |
fun initialize() =
|
paulson@4300
|
1257 |
(fullTrace:=[]; trail := []; ntrail := 0;
|
paulson@4300
|
1258 |
nclosed := 0; ntried := 1);
|
paulson@4300
|
1259 |
|
paulson@4300
|
1260 |
|
paulson@2854
|
1261 |
(*Tactic using tableau engine and proof reconstruction.
|
paulson@4391
|
1262 |
"start" is CPU time at start, for printing SEARCH time
|
paulson@4391
|
1263 |
(also prints reconstruction time)
|
paulson@2854
|
1264 |
"lim" is depth limit.*)
|
paulson@4391
|
1265 |
fun timing_depth_tac start cs lim i st =
|
paulson@4323
|
1266 |
(initialize();
|
paulson@4323
|
1267 |
let val {sign,...} = rep_thm st
|
paulson@4323
|
1268 |
val skoprem = fromSubgoal (List.nth(prems_of st, i-1))
|
paulson@4323
|
1269 |
val hyps = strip_imp_prems skoprem
|
paulson@4323
|
1270 |
and concl = strip_imp_concl skoprem
|
paulson@4323
|
1271 |
fun cont (tacs,_,choices) =
|
paulson@4323
|
1272 |
let val start = startTiming()
|
paulson@4323
|
1273 |
in
|
paulson@4323
|
1274 |
case Seq.pull(EVERY' (rev tacs) i st) of
|
paulson@4323
|
1275 |
None => (writeln ("PROOF FAILED for depth " ^
|
paulson@4323
|
1276 |
Int.toString lim);
|
paulson@5463
|
1277 |
if !trace then writeln "************************\n"
|
paulson@5463
|
1278 |
else ();
|
paulson@4323
|
1279 |
backtrack choices)
|
paulson@4323
|
1280 |
| cell => (if (!trace orelse !stats)
|
paulson@4323
|
1281 |
then writeln (endTiming start ^ " for reconstruction")
|
paulson@4323
|
1282 |
else ();
|
paulson@4323
|
1283 |
Seq.make(fn()=> cell))
|
paulson@4323
|
1284 |
end
|
paulson@4391
|
1285 |
in prove (sign, start, cs, [initBranch (mkGoal concl :: hyps, lim)], cont)
|
paulson@4323
|
1286 |
end
|
paulson@4323
|
1287 |
handle PROVE => Seq.empty);
|
paulson@2854
|
1288 |
|
paulson@4391
|
1289 |
(*Public version with fixed depth*)
|
paulson@4391
|
1290 |
fun depth_tac cs lim i st = timing_depth_tac (startTiming()) cs lim i st;
|
paulson@4391
|
1291 |
|
paulson@4391
|
1292 |
fun blast_tac cs i st =
|
paulson@5463
|
1293 |
((DEEPEN (1,20) (timing_depth_tac (startTiming()) cs) 0) i
|
paulson@5463
|
1294 |
THEN flexflex_tac) st
|
paulson@4391
|
1295 |
handle TRANS s => (warning ("Blast_tac: " ^ s); Seq.empty);
|
paulson@2854
|
1296 |
|
wenzelm@4078
|
1297 |
fun Blast_tac i = blast_tac (Data.claset()) i;
|
paulson@2854
|
1298 |
|
paulson@2924
|
1299 |
|
paulson@2924
|
1300 |
(*** For debugging: these apply the prover to a subgoal and return
|
paulson@2924
|
1301 |
the resulting tactics, trace, etc. ***)
|
paulson@2924
|
1302 |
|
paulson@2924
|
1303 |
(*Translate subgoal i from a proof state*)
|
paulson@2924
|
1304 |
fun trygl cs lim i =
|
paulson@4300
|
1305 |
(initialize();
|
paulson@2924
|
1306 |
let val st = topthm()
|
paulson@3030
|
1307 |
val {sign,...} = rep_thm st
|
paulson@4065
|
1308 |
val skoprem = fromSubgoal (List.nth(prems_of st, i-1))
|
paulson@2924
|
1309 |
val hyps = strip_imp_prems skoprem
|
paulson@2924
|
1310 |
and concl = strip_imp_concl skoprem
|
paulson@4391
|
1311 |
in timeap prove (sign, startTiming(), cs,
|
paulson@4391
|
1312 |
[initBranch (mkGoal concl :: hyps, lim)], I)
|
paulson@2924
|
1313 |
end
|
paulson@2924
|
1314 |
handle Subscript => error("There is no subgoal " ^ Int.toString i));
|
paulson@2924
|
1315 |
|
wenzelm@4078
|
1316 |
fun Trygl lim i = trygl (Data.claset()) lim i;
|
paulson@2924
|
1317 |
|
paulson@2924
|
1318 |
(*Read a string to make an initial, singleton branch*)
|
paulson@2924
|
1319 |
fun readGoal sign s = read_cterm sign (s,propT) |>
|
paulson@4065
|
1320 |
term_of |> fromTerm |> rand |> mkGoal;
|
paulson@2924
|
1321 |
|
paulson@2924
|
1322 |
fun tryInThy thy lim s =
|
paulson@4300
|
1323 |
(initialize();
|
wenzelm@6391
|
1324 |
timeap prove (Theory.sign_of thy,
|
paulson@4391
|
1325 |
startTiming(),
|
paulson@4323
|
1326 |
Data.claset(),
|
wenzelm@6391
|
1327 |
[initBranch ([readGoal (Theory.sign_of thy) s], lim)],
|
paulson@4323
|
1328 |
I));
|
paulson@2924
|
1329 |
|
paulson@2924
|
1330 |
|
wenzelm@5926
|
1331 |
(** method setup **)
|
wenzelm@5926
|
1332 |
|
wenzelm@7559
|
1333 |
fun blast_args m =
|
wenzelm@7559
|
1334 |
Method.sectioned_args (K (Args.bang_facts -- Scan.lift (Scan.option Args.nat))) Data.cla_modifiers m;
|
wenzelm@7155
|
1335 |
|
wenzelm@7559
|
1336 |
fun blast_meth (prems, None) = Data.cla_meth' blast_tac prems
|
wenzelm@7559
|
1337 |
| blast_meth (prems, Some lim) = Data.cla_meth' (fn cs => depth_tac cs lim) prems;
|
wenzelm@7155
|
1338 |
|
wenzelm@7155
|
1339 |
val setup = [Method.add_methods [("blast", blast_args blast_meth, "tableau prover")]];
|
wenzelm@5926
|
1340 |
|
wenzelm@5926
|
1341 |
|
paulson@2854
|
1342 |
end;
|