--- a/src/HOL/Tools/Sledgehammer/sledgehammer_fact_preprocessor.ML Fri Jun 25 16:03:34 2010 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,571 +0,0 @@
-(* Title: HOL/Tools/Sledgehammer/sledgehammer_fact_preprocessor.ML
- Author: Jia Meng, Cambridge University Computer Laboratory
- Author: Jasmin Blanchette, TU Muenchen
-
-Transformation of axiom rules (elim/intro/etc) into CNF forms.
-*)
-
-signature SLEDGEHAMMER_FACT_PREPROCESSOR =
-sig
- type cnf_thm = thm * ((string * int) * thm)
-
- val sledgehammer_prefix: string
- val chained_prefix: string
- val trace: bool Unsynchronized.ref
- val trace_msg: (unit -> string) -> unit
- val name_thms_pair_from_ref :
- Proof.context -> thm list -> Facts.ref -> string * thm list
- val skolem_theory_name: string
- val skolem_prefix: string
- val skolem_infix: string
- val is_skolem_const_name: string -> bool
- val num_type_args: theory -> string -> int
- val cnf_axiom: theory -> thm -> thm list
- val multi_base_blacklist: string list
- val is_theorem_bad_for_atps: thm -> bool
- val type_has_topsort: typ -> bool
- val cnf_rules_pairs : theory -> (string * thm) list -> cnf_thm list
- val saturate_skolem_cache: theory -> theory option
- val auto_saturate_skolem_cache: bool Unsynchronized.ref
- val neg_clausify: thm -> thm list
- val neg_conjecture_clauses:
- Proof.context -> thm -> int -> thm list list * (string * typ) list
- val setup: theory -> theory
-end;
-
-structure Sledgehammer_Fact_Preprocessor : SLEDGEHAMMER_FACT_PREPROCESSOR =
-struct
-
-type cnf_thm = thm * ((string * int) * thm)
-
-val sledgehammer_prefix = "Sledgehammer" ^ Long_Name.separator
-
-(* Used to label theorems chained into the goal. *)
-val chained_prefix = sledgehammer_prefix ^ "chained_"
-
-val trace = Unsynchronized.ref false;
-fun trace_msg msg = if !trace then tracing (msg ()) else ();
-
-fun name_thms_pair_from_ref ctxt chained_ths xref =
- let
- val ths = ProofContext.get_fact ctxt xref
- val name = Facts.string_of_ref xref
- |> forall (member Thm.eq_thm chained_ths) ths
- ? prefix chained_prefix
- in (name, ths) end
-
-val skolem_theory_name = sledgehammer_prefix ^ "Sko"
-val skolem_prefix = "sko_"
-val skolem_infix = "$"
-
-val type_has_topsort = Term.exists_subtype
- (fn TFree (_, []) => true
- | TVar (_, []) => true
- | _ => false);
-
-
-(**** Transformation of Elimination Rules into First-Order Formulas****)
-
-val cfalse = cterm_of @{theory HOL} HOLogic.false_const;
-val ctp_false = cterm_of @{theory HOL} (HOLogic.mk_Trueprop HOLogic.false_const);
-
-(*Converts an elim-rule into an equivalent theorem that does not have the
- predicate variable. Leaves other theorems unchanged. We simply instantiate the
- conclusion variable to False.*)
-fun transform_elim th =
- case concl_of th of (*conclusion variable*)
- @{const Trueprop} $ (v as Var (_, @{typ bool})) =>
- Thm.instantiate ([], [(cterm_of @{theory HOL} v, cfalse)]) th
- | v as Var(_, @{typ prop}) =>
- Thm.instantiate ([], [(cterm_of @{theory HOL} v, ctp_false)]) th
- | _ => th;
-
-(*To enforce single-threading*)
-exception Clausify_failure of theory;
-
-
-(**** SKOLEMIZATION BY INFERENCE (lcp) ****)
-
-(*Keep the full complexity of the original name*)
-fun flatten_name s = space_implode "_X" (Long_Name.explode s);
-
-fun skolem_name thm_name j var_name =
- skolem_prefix ^ thm_name ^ "_" ^ Int.toString j ^
- skolem_infix ^ (if var_name = "" then "g" else flatten_name var_name)
-
-(* Hack: Could return false positives (e.g., a user happens to declare a
- constant called "SomeTheory.sko_means_shoe_in_$wedish". *)
-val is_skolem_const_name =
- Long_Name.base_name
- #> String.isPrefix skolem_prefix andf String.isSubstring skolem_infix
-
-(* The number of type arguments of a constant, zero if it's monomorphic. For
- (instances of) Skolem pseudoconstants, this information is encoded in the
- constant name. *)
-fun num_type_args thy s =
- if String.isPrefix skolem_theory_name s then
- s |> unprefix skolem_theory_name
- |> space_explode skolem_infix |> hd
- |> space_explode "_" |> List.last |> Int.fromString |> the
- else
- (s, Sign.the_const_type thy s) |> Sign.const_typargs thy |> length
-
-fun rhs_extra_types lhsT rhs =
- let val lhs_vars = Term.add_tfreesT lhsT []
- fun add_new_TFrees (TFree v) =
- if member (op =) lhs_vars v then I else insert (op =) (TFree v)
- | add_new_TFrees _ = I
- val rhs_consts = fold_aterms (fn Const c => insert (op =) c | _ => I) rhs []
- in fold (#2 #> Term.fold_atyps add_new_TFrees) rhs_consts [] end;
-
-fun skolem_type_and_args bound_T body =
- let
- val args1 = OldTerm.term_frees body
- val Ts1 = map type_of args1
- val Ts2 = rhs_extra_types (Ts1 ---> bound_T) body
- val args2 = map (fn T => Free (gensym "vsk", T)) Ts2
- in (Ts2 ---> Ts1 ---> bound_T, args2 @ args1) end
-
-(* Traverse a theorem, declaring Skolem function definitions. String "s" is the
- suggested prefix for the Skolem constants. *)
-fun declare_skolem_funs s th thy =
- let
- val skolem_count = Unsynchronized.ref 0 (* FIXME ??? *)
- fun dec_sko (Const (@{const_name Ex}, _) $ (body as Abs (s', T, p)))
- (axs, thy) =
- (*Existential: declare a Skolem function, then insert into body and continue*)
- let
- val id = skolem_name s (Unsynchronized.inc skolem_count) s'
- val (cT, args) = skolem_type_and_args T body
- val rhs = list_abs_free (map dest_Free args,
- HOLogic.choice_const T $ body)
- (*Forms a lambda-abstraction over the formal parameters*)
- val (c, thy) =
- Sign.declare_const ((Binding.conceal (Binding.name id), cT), NoSyn) thy
- val cdef = id ^ "_def"
- val ((_, ax), thy) =
- Thm.add_def true false (Binding.name cdef, Logic.mk_equals (c, rhs)) thy
- val ax' = Drule.export_without_context ax
- in dec_sko (subst_bound (list_comb (c, args), p)) (ax' :: axs, thy) end
- | dec_sko (Const (@{const_name All}, _) $ (Abs (a, T, p))) thx =
- (*Universal quant: insert a free variable into body and continue*)
- let val fname = Name.variant (OldTerm.add_term_names (p, [])) a
- in dec_sko (subst_bound (Free (fname, T), p)) thx end
- | dec_sko (@{const "op &"} $ p $ q) thx = dec_sko q (dec_sko p thx)
- | dec_sko (@{const "op |"} $ p $ q) thx = dec_sko q (dec_sko p thx)
- | dec_sko (@{const Trueprop} $ p) thx = dec_sko p thx
- | dec_sko _ thx = thx
- in dec_sko (prop_of th) ([], thy) end
-
-fun mk_skolem_id t =
- let val T = fastype_of t in
- Const (@{const_name skolem_id}, T --> T) $ t
- end
-
-fun quasi_beta_eta_contract (Abs (s, T, t')) =
- Abs (s, T, quasi_beta_eta_contract t')
- | quasi_beta_eta_contract t = Envir.beta_eta_contract t
-
-(*Traverse a theorem, accumulating Skolem function definitions.*)
-fun assume_skolem_funs s th =
- let
- val skolem_count = Unsynchronized.ref 0 (* FIXME ??? *)
- fun dec_sko (Const (@{const_name Ex}, _) $ (body as Abs (s', T, p))) defs =
- (*Existential: declare a Skolem function, then insert into body and continue*)
- let
- val skos = map (#1 o Logic.dest_equals) defs (*existing sko fns*)
- val args = subtract (op =) skos (OldTerm.term_frees body) (*the formal parameters*)
- val Ts = map type_of args
- val cT = Ts ---> T (* FIXME: use "skolem_type_and_args" *)
- val id = skolem_name s (Unsynchronized.inc skolem_count) s'
- val c = Free (id, cT) (* FIXME: needed? ### *)
- (* Forms a lambda-abstraction over the formal parameters *)
- val rhs =
- list_abs_free (map dest_Free args,
- HOLogic.choice_const T
- $ quasi_beta_eta_contract body)
- |> mk_skolem_id
- val def = Logic.mk_equals (c, rhs)
- val comb = list_comb (rhs, args)
- in dec_sko (subst_bound (comb, p)) (def :: defs) end
- | dec_sko (Const (@{const_name All},_) $ Abs (a, T, p)) defs =
- (*Universal quant: insert a free variable into body and continue*)
- let val fname = Name.variant (OldTerm.add_term_names (p,[])) a
- in dec_sko (subst_bound (Free(fname,T), p)) defs end
- | dec_sko (@{const "op &"} $ p $ q) defs = dec_sko q (dec_sko p defs)
- | dec_sko (@{const "op |"} $ p $ q) defs = dec_sko q (dec_sko p defs)
- | dec_sko (@{const Trueprop} $ p) defs = dec_sko p defs
- | dec_sko _ defs = defs
- in dec_sko (prop_of th) [] end;
-
-
-(**** REPLACING ABSTRACTIONS BY COMBINATORS ****)
-
-(*Returns the vars of a theorem*)
-fun vars_of_thm th =
- map (Thm.cterm_of (theory_of_thm th) o Var) (Thm.fold_terms Term.add_vars th []);
-
-val fun_cong_all = @{thm expand_fun_eq [THEN iffD1]}
-
-(* Removes the lambdas from an equation of the form t = (%x. u). *)
-fun extensionalize th =
- case prop_of th of
- _ $ (Const (@{const_name "op ="}, Type (_, [Type (@{type_name fun}, _), _]))
- $ _ $ Abs (s, _, _)) => extensionalize (th RS fun_cong_all)
- | _ => th
-
-fun is_quasi_lambda_free (Const (@{const_name skolem_id}, _) $ _) = true
- | is_quasi_lambda_free (t1 $ t2) =
- is_quasi_lambda_free t1 andalso is_quasi_lambda_free t2
- | is_quasi_lambda_free (Abs _) = false
- | is_quasi_lambda_free _ = true
-
-val [f_B,g_B] = map (cterm_of @{theory}) (OldTerm.term_vars (prop_of @{thm abs_B}));
-val [g_C,f_C] = map (cterm_of @{theory}) (OldTerm.term_vars (prop_of @{thm abs_C}));
-val [f_S,g_S] = map (cterm_of @{theory}) (OldTerm.term_vars (prop_of @{thm abs_S}));
-
-(*FIXME: requires more use of cterm constructors*)
-fun abstract ct =
- let
- val thy = theory_of_cterm ct
- val Abs(x,_,body) = term_of ct
- val Type(@{type_name fun}, [xT,bodyT]) = typ_of (ctyp_of_term ct)
- val cxT = ctyp_of thy xT and cbodyT = ctyp_of thy bodyT
- fun makeK() = instantiate' [SOME cxT, SOME cbodyT] [SOME (cterm_of thy body)] @{thm abs_K}
- in
- case body of
- Const _ => makeK()
- | Free _ => makeK()
- | Var _ => makeK() (*though Var isn't expected*)
- | Bound 0 => instantiate' [SOME cxT] [] @{thm abs_I} (*identity: I*)
- | rator$rand =>
- if loose_bvar1 (rator,0) then (*C or S*)
- if loose_bvar1 (rand,0) then (*S*)
- let val crator = cterm_of thy (Abs(x,xT,rator))
- val crand = cterm_of thy (Abs(x,xT,rand))
- val abs_S' = cterm_instantiate [(f_S,crator),(g_S,crand)] @{thm abs_S}
- val (_,rhs) = Thm.dest_equals (cprop_of abs_S')
- in
- Thm.transitive abs_S' (Conv.binop_conv abstract rhs)
- end
- else (*C*)
- let val crator = cterm_of thy (Abs(x,xT,rator))
- val abs_C' = cterm_instantiate [(f_C,crator),(g_C,cterm_of thy rand)] @{thm abs_C}
- val (_,rhs) = Thm.dest_equals (cprop_of abs_C')
- in
- Thm.transitive abs_C' (Conv.fun_conv (Conv.arg_conv abstract) rhs)
- end
- else if loose_bvar1 (rand,0) then (*B or eta*)
- if rand = Bound 0 then Thm.eta_conversion ct
- else (*B*)
- let val crand = cterm_of thy (Abs(x,xT,rand))
- val crator = cterm_of thy rator
- val abs_B' = cterm_instantiate [(f_B,crator),(g_B,crand)] @{thm abs_B}
- val (_,rhs) = Thm.dest_equals (cprop_of abs_B')
- in Thm.transitive abs_B' (Conv.arg_conv abstract rhs) end
- else makeK()
- | _ => raise Fail "abstract: Bad term"
- end;
-
-(* Traverse a theorem, remplacing lambda-abstractions with combinators. *)
-fun do_introduce_combinators ct =
- if is_quasi_lambda_free (term_of ct) then
- Thm.reflexive ct
- else case term_of ct of
- Abs _ =>
- let
- val (cv, cta) = Thm.dest_abs NONE ct
- val (v, _) = dest_Free (term_of cv)
- val u_th = do_introduce_combinators cta
- val cu = Thm.rhs_of u_th
- val comb_eq = abstract (Thm.cabs cv cu)
- in Thm.transitive (Thm.abstract_rule v cv u_th) comb_eq end
- | _ $ _ =>
- let val (ct1, ct2) = Thm.dest_comb ct in
- Thm.combination (do_introduce_combinators ct1)
- (do_introduce_combinators ct2)
- end
-
-fun introduce_combinators th =
- if is_quasi_lambda_free (prop_of th) then
- th
- else
- let
- val th = Drule.eta_contraction_rule th
- val eqth = do_introduce_combinators (cprop_of th)
- in Thm.equal_elim eqth th end
- handle THM (msg, _, _) =>
- (warning ("Error in the combinator translation of " ^
- Display.string_of_thm_without_context th ^
- "\nException message: " ^ msg ^ ".");
- (* A type variable of sort "{}" will make abstraction fail. *)
- TrueI)
-
-(*cterms are used throughout for efficiency*)
-val cTrueprop = Thm.cterm_of @{theory HOL} HOLogic.Trueprop;
-
-(*cterm version of mk_cTrueprop*)
-fun c_mkTrueprop A = Thm.capply cTrueprop A;
-
-(*Given an abstraction over n variables, replace the bound variables by free
- ones. Return the body, along with the list of free variables.*)
-fun c_variant_abs_multi (ct0, vars) =
- let val (cv,ct) = Thm.dest_abs NONE ct0
- in c_variant_abs_multi (ct, cv::vars) end
- handle CTERM _ => (ct0, rev vars);
-
-(*Given the definition of a Skolem function, return a theorem to replace
- an existential formula by a use of that function.
- Example: "EX x. x : A & x ~: B ==> sko A B : A & sko A B ~: B" [.] *)
-fun skolem_theorem_of_def inline def =
- let
- val (c, rhs) = def |> Drule.legacy_freeze_thaw |> #1 |> cprop_of
- |> Thm.dest_equals
- val rhs' = rhs |> inline ? (snd o Thm.dest_comb)
- val (ch, frees) = c_variant_abs_multi (rhs', [])
- val (chilbert, cabs) = ch |> Thm.dest_comb
- val thy = Thm.theory_of_cterm chilbert
- val t = Thm.term_of chilbert
- val T =
- case t of
- Const (@{const_name Eps}, Type (@{type_name fun}, [_, T])) => T
- | _ => raise TERM ("skolem_theorem_of_def: expected \"Eps\"", [t])
- val cex = Thm.cterm_of thy (HOLogic.exists_const T)
- val ex_tm = c_mkTrueprop (Thm.capply cex cabs)
- and conc =
- Drule.list_comb (if inline then rhs else c, frees)
- |> Drule.beta_conv cabs |> c_mkTrueprop
- fun tacf [prem] =
- (if inline then rewrite_goals_tac @{thms skolem_id_def_raw}
- else rewrite_goals_tac [def])
- THEN rtac ((prem |> inline ? rewrite_rule @{thms skolem_id_def_raw})
- RS @{thm someI_ex}) 1
- in Goal.prove_internal [ex_tm] conc tacf
- |> forall_intr_list frees
- |> Thm.forall_elim_vars 0 (*Introduce Vars, but don't discharge defs.*)
- |> Thm.varifyT_global
- end;
-
-
-(*Converts an Isabelle theorem (intro, elim or simp format, even higher-order) into NNF.*)
-fun to_nnf th ctxt0 =
- let val th1 = th |> transform_elim |> zero_var_indexes
- val ((_, [th2]), ctxt) = Variable.import true [th1] ctxt0
- val th3 = th2 |> Conv.fconv_rule Object_Logic.atomize
- |> extensionalize
- |> Meson.make_nnf ctxt
- in (th3, ctxt) end;
-
-(*Generate Skolem functions for a theorem supplied in nnf*)
-fun skolem_theorems_of_assume s th =
- map (skolem_theorem_of_def true o Thm.assume o cterm_of (theory_of_thm th))
- (assume_skolem_funs s th)
-
-
-(*** Blacklisting (more in "Sledgehammer_Fact_Filter") ***)
-
-val max_lambda_nesting = 3
-
-fun term_has_too_many_lambdas max (t1 $ t2) =
- exists (term_has_too_many_lambdas max) [t1, t2]
- | term_has_too_many_lambdas max (Abs (_, _, t)) =
- max = 0 orelse term_has_too_many_lambdas (max - 1) t
- | term_has_too_many_lambdas _ _ = false
-
-fun is_formula_type T = (T = HOLogic.boolT orelse T = propT)
-
-(* Don't count nested lambdas at the level of formulas, since they are
- quantifiers. *)
-fun formula_has_too_many_lambdas Ts (Abs (_, T, t)) =
- formula_has_too_many_lambdas (T :: Ts) t
- | formula_has_too_many_lambdas Ts t =
- if is_formula_type (fastype_of1 (Ts, t)) then
- exists (formula_has_too_many_lambdas Ts) (#2 (strip_comb t))
- else
- term_has_too_many_lambdas max_lambda_nesting t
-
-(* The max apply depth of any "metis" call in "Metis_Examples" (on 31-10-2007)
- was 11. *)
-val max_apply_depth = 15
-
-fun apply_depth (f $ t) = Int.max (apply_depth f, apply_depth t + 1)
- | apply_depth (Abs (_, _, t)) = apply_depth t
- | apply_depth _ = 0
-
-fun is_formula_too_complex t =
- apply_depth t > max_apply_depth orelse Meson.too_many_clauses NONE t orelse
- formula_has_too_many_lambdas [] t
-
-fun is_strange_thm th =
- case head_of (concl_of th) of
- Const (a, _) => (a <> @{const_name Trueprop} andalso
- a <> @{const_name "=="})
- | _ => false;
-
-fun is_theorem_bad_for_atps thm =
- let val t = prop_of thm in
- is_formula_too_complex t orelse exists_type type_has_topsort t orelse
- is_strange_thm thm
- end
-
-(* FIXME: put other record thms here, or declare as "no_atp" *)
-val multi_base_blacklist =
- ["defs", "select_defs", "update_defs", "induct", "inducts", "split", "splits",
- "split_asm", "cases", "ext_cases"];
-
-fun fake_name th =
- if Thm.has_name_hint th then flatten_name (Thm.get_name_hint th)
- else gensym "unknown_thm_";
-
-(*Skolemize a named theorem, with Skolem functions as additional premises.*)
-fun skolemize_theorem s th =
- if member (op =) multi_base_blacklist (Long_Name.base_name s) orelse
- is_theorem_bad_for_atps th then
- []
- else
- let
- val ctxt0 = Variable.global_thm_context th
- val (nnfth, ctxt) = to_nnf th ctxt0
- val defs = skolem_theorems_of_assume s nnfth
- val (cnfs, ctxt) = Meson.make_cnf defs nnfth ctxt
- in
- cnfs |> map introduce_combinators
- |> Variable.export ctxt ctxt0
- |> Meson.finish_cnf
- end
- handle THM _ => []
-
-(*The cache prevents repeated clausification of a theorem, and also repeated declaration of
- Skolem functions.*)
-structure ThmCache = Theory_Data
-(
- type T = thm list Thmtab.table * unit Symtab.table;
- val empty = (Thmtab.empty, Symtab.empty);
- val extend = I;
- fun merge ((cache1, seen1), (cache2, seen2)) : T =
- (Thmtab.merge (K true) (cache1, cache2), Symtab.merge (K true) (seen1, seen2));
-);
-
-val lookup_cache = Thmtab.lookup o #1 o ThmCache.get;
-val already_seen = Symtab.defined o #2 o ThmCache.get;
-
-val update_cache = ThmCache.map o apfst o Thmtab.update;
-fun mark_seen name = ThmCache.map (apsnd (Symtab.update (name, ())));
-
-(* Convert Isabelle theorems into axiom clauses. *)
-fun cnf_axiom thy th0 =
- let val th = Thm.transfer thy th0 in
- case lookup_cache thy th of
- SOME cls => cls
- | NONE => map Thm.close_derivation (skolemize_theorem (fake_name th) th)
- end;
-
-
-(**** Translate a set of theorems into CNF ****)
-
-(*The combination of rev and tail recursion preserves the original order*)
-fun cnf_rules_pairs thy =
- let
- fun do_one _ [] = []
- | do_one ((name, k), th) (cls :: clss) =
- (cls, ((name, k), th)) :: do_one ((name, k + 1), th) clss
- fun do_all pairs [] = pairs
- | do_all pairs ((name, th) :: ths) =
- let
- val new_pairs = do_one ((name, 0), th) (cnf_axiom thy th)
- handle THM _ => []
- in do_all (new_pairs @ pairs) ths end
- in do_all [] o rev end
-
-
-(**** Convert all facts of the theory into FOL or HOL clauses ****)
-
-local
-
-fun skolem_def (name, th) thy =
- let val ctxt0 = Variable.global_thm_context th in
- case try (to_nnf th) ctxt0 of
- NONE => (NONE, thy)
- | SOME (nnfth, ctxt) =>
- let val (defs, thy') = declare_skolem_funs (flatten_name name) nnfth thy
- in (SOME (th, ctxt0, ctxt, nnfth, defs), thy') end
- end;
-
-fun skolem_cnfs (th, ctxt0, ctxt, nnfth, defs) =
- let
- val (cnfs, ctxt) =
- Meson.make_cnf (map (skolem_theorem_of_def false) defs) nnfth ctxt
- val cnfs' = cnfs
- |> map introduce_combinators
- |> Variable.export ctxt ctxt0
- |> Meson.finish_cnf
- |> map Thm.close_derivation;
- in (th, cnfs') end;
-
-in
-
-fun saturate_skolem_cache thy =
- let
- val facts = PureThy.facts_of thy;
- val new_facts = (facts, []) |-> Facts.fold_static (fn (name, ths) =>
- if Facts.is_concealed facts name orelse already_seen thy name then I
- else cons (name, ths));
- val new_thms = (new_facts, []) |-> fold (fn (name, ths) =>
- if member (op =) multi_base_blacklist (Long_Name.base_name name) then
- I
- else
- fold_index (fn (i, th) =>
- if is_theorem_bad_for_atps th orelse
- is_some (lookup_cache thy th) then
- I
- else
- cons (name ^ "_" ^ string_of_int (i + 1), Thm.transfer thy th)) ths)
- in
- if null new_facts then
- NONE
- else
- let
- val (defs, thy') = thy
- |> fold (mark_seen o #1) new_facts
- |> fold_map skolem_def (sort_distinct (Thm.thm_ord o pairself snd) new_thms)
- |>> map_filter I;
- val cache_entries = Par_List.map skolem_cnfs defs;
- in SOME (fold update_cache cache_entries thy') end
- end;
-
-end;
-
-(* For emergency use where the Skolem cache causes problems. *)
-val auto_saturate_skolem_cache = Unsynchronized.ref true
-
-fun conditionally_saturate_skolem_cache thy =
- if !auto_saturate_skolem_cache then saturate_skolem_cache thy else NONE
-
-
-(*** Converting a subgoal into negated conjecture clauses. ***)
-
-fun neg_skolemize_tac ctxt =
- EVERY' [rtac ccontr, Object_Logic.atomize_prems_tac, Meson.skolemize_tac ctxt]
-
-val neg_clausify =
- single
- #> Meson.make_clauses_unsorted
- #> map introduce_combinators
- #> Meson.finish_cnf
-
-fun neg_conjecture_clauses ctxt st0 n =
- let
- (* "Option" is thrown if the assumptions contain schematic variables. *)
- val st = Seq.hd (neg_skolemize_tac ctxt n st0) handle Option.Option => st0
- val ({params, prems, ...}, _) =
- Subgoal.focus (Variable.set_body false ctxt) n st
- in (map neg_clausify prems, map (dest_Free o term_of o #2) params) end
-
-
-(** setup **)
-
-val setup =
- perhaps conditionally_saturate_skolem_cache
- #> Theory.at_end conditionally_saturate_skolem_cache
-
-end;