(* Title: HOL/Decision_Procs/cooper_tac.ML
Author: Amine Chaieb, TU Muenchen
*)
signature COOPER_TAC =
sig
val linz_tac: Proof.context -> bool -> int -> tactic
end
structure Cooper_Tac: COOPER_TAC =
struct
val cooper_ss = simpset_of @{context};
fun prepare_for_linz q fm =
let
val ps = Logic.strip_params fm
val hs = map HOLogic.dest_Trueprop (Logic.strip_assums_hyp fm)
val c = HOLogic.dest_Trueprop (Logic.strip_assums_concl fm)
fun mk_all ((s, T), (P,n)) =
if Term.is_dependent P then
(HOLogic.all_const T $ Abs (s, T, P), n)
else (incr_boundvars ~1 P, n-1)
fun mk_all2 (v, t) = HOLogic.all_const (fastype_of v) $ lambda v t;
val rhs = hs
val np = length ps
val (fm',np) = List.foldr (fn ((x, T), (fm,n)) => mk_all ((x, T), (fm,n)))
(List.foldr HOLogic.mk_imp c rhs, np) ps
val (vs, _) = List.partition (fn t => q orelse (type_of t) = @{typ nat})
(Misc_Legacy.term_frees fm' @ Misc_Legacy.term_vars fm');
val fm2 = List.foldr mk_all2 fm' vs
in (fm2, np + length vs, length rhs) end;
(*Object quantifier to meta --*)
fun spec_step n th = if n = 0 then th else (spec_step (n - 1) th) RS spec;
(* object implication to meta---*)
fun mp_step n th = if n = 0 then th else (mp_step (n - 1) th) RS mp;
fun linz_tac ctxt q = Object_Logic.atomize_prems_tac ctxt THEN' SUBGOAL (fn (g, i) =>
let
(* Transform the term*)
val (t, np, nh) = prepare_for_linz q g;
(* Some simpsets for dealing with mod div abs and nat*)
val mod_div_simpset =
put_simpset HOL_basic_ss ctxt
addsimps @{thms refl mod_add_eq mod_add_left_eq
mod_add_right_eq
div_add1_eq [symmetric] zdiv_zadd1_eq [symmetric]
mod_self
div_by_0 mod_by_0 div_0 mod_0
div_by_1 mod_by_1 div_by_Suc_0 mod_by_Suc_0
Suc_eq_plus1}
addsimps @{thms ac_simps}
addsimprocs [@{simproc cancel_div_mod_nat}, @{simproc cancel_div_mod_int}]
val simpset0 =
put_simpset HOL_basic_ss ctxt
addsimps @{thms minus_div_mult_eq_mod [symmetric] Suc_eq_plus1 simp_thms}
|> fold Splitter.add_split @{thms split_zdiv split_zmod split_div' split_min split_max}
(* Simp rules for changing (n::int) to int n *)
val simpset1 =
put_simpset HOL_basic_ss ctxt
addsimps @{thms zdvd_int} @ [@{thm "of_nat_add"}, @{thm "of_nat_mult"}] @
map (fn r => r RS sym) @{thms of_nat_numeral [where ?'a = int] int_int_eq zle_int of_nat_less_iff [where ?'a = int]}
|> Splitter.add_split @{thm zdiff_int_split}
(*simp rules for elimination of int n*)
val simpset2 =
put_simpset HOL_basic_ss ctxt
addsimps [@{thm nat_0_le}, @{thm all_nat}, @{thm ex_nat}, @{thm zero_le_numeral}, @{thm order_refl}(* FIXME: necessary? *),
@{thm of_nat_0 [where ?'a = int]}, @{thm of_nat_1 [where ?'a = int]}]
|> fold Simplifier.add_cong @{thms conj_le_cong imp_le_cong}
(* simp rules for elimination of abs *)
val simpset3 = put_simpset HOL_basic_ss ctxt |> Splitter.add_split @{thm abs_split}
val ct = Thm.cterm_of ctxt (HOLogic.mk_Trueprop t)
(* Theorem for the nat --> int transformation *)
val pre_thm = Seq.hd (EVERY
[simp_tac mod_div_simpset 1, simp_tac simpset0 1,
TRY (simp_tac simpset1 1), TRY (simp_tac simpset2 1),
TRY (simp_tac simpset3 1), TRY (simp_tac (put_simpset cooper_ss ctxt) 1)]
(Thm.trivial ct))
fun assm_tac i = REPEAT_DETERM_N nh (assume_tac ctxt i)
(* The result of the quantifier elimination *)
val (th, tac) =
(case Thm.prop_of pre_thm of
Const (@{const_name Pure.imp}, _) $ (Const (@{const_name Trueprop}, _) $ t1) $ _ =>
let
val pth = linzqe_oracle (ctxt, Envir.eta_long [] t1)
in
((pth RS iffD2) RS pre_thm,
assm_tac (i + 1) THEN (if q then I else TRY) (resolve_tac ctxt [TrueI] i))
end
| _ => (pre_thm, assm_tac i))
in resolve_tac ctxt [mp_step nh (spec_step np th)] i THEN tac end);
end