signature TRANSFER_TAC =
sig
val transfer_tac: thm list -> int -> tactic
val setup: (theory -> theory) list
end;
structure Transfer: TRANSFER_TAC =
struct
(* TODO: make this list extensible *)
val star_consts =
[ "StarType.star_of", "StarType.Ifun"
, "StarType.unstar", "StarType.Iset" ]
structure TransferData = TheoryDataFun
(struct
val name = "HOL/transfer";
type T = {
intros: thm list,
unfolds: thm list,
refolds: thm list,
consts: string list
};
val empty = {intros = [], unfolds = [], refolds = [], consts = star_consts};
val copy = I;
val extend = I;
fun merge _
({intros = intros1, unfolds = unfolds1,
refolds = refolds1, consts = consts1},
{intros = intros2, unfolds = unfolds2,
refolds = refolds2, consts = consts2}) =
{intros = Drule.merge_rules (intros1, intros2),
unfolds = Drule.merge_rules (unfolds1, unfolds2),
refolds = Drule.merge_rules (refolds1, refolds2),
consts = merge_lists consts1 consts2};
fun print _ _ = ();
end);
val transfer_start = thm "transfer_start"
fun unstar_typ (Type ("StarType.star",[t])) = unstar_typ t
| unstar_typ (Type (a, Ts)) = Type (a, map unstar_typ Ts)
| unstar_typ T = T
fun unstar_term consts term =
let
fun delete a = exists (fn x => x = a) consts
fun unstar (Const(a,T) $ t) = if (delete a) then (unstar t)
else (Const(a,unstar_typ T) $ unstar t)
| unstar (f $ t) = unstar f $ unstar t
| unstar (Const(a,T)) = Const(a,unstar_typ T)
| unstar (Abs(a,T,t)) = Abs(a,unstar_typ T,unstar t)
| unstar t = t
in
unstar term
end
val atomizers = map thm ["atomize_all", "atomize_imp", "atomize_eq"]
fun transfer_thm_of thy ths t =
let
val {intros,unfolds,refolds,consts} = TransferData.get thy
val (_$_$t') = concl_of (Tactic.rewrite true unfolds (cterm_of thy t))
val u = unstar_term consts t'
val ct = cterm_of thy (Logic.mk_equals (t,u))
val tacs =
[ rewrite_goals_tac atomizers
, match_tac [transitive_thm] 1
, resolve_tac [transfer_start] 1
, REPEAT_ALL_NEW (resolve_tac intros) 1
, match_tac [reflexive_thm] 1 ]
in
prove_goalw_cterm (ths @ refolds @ unfolds) ct (fn _ => tacs)
end
fun transfer_tac ths =
SUBGOAL (fn (t,i) =>
(fn th =>
let val thy = theory_of_thm th
val tr = transfer_thm_of thy ths t
in rewrite_goals_tac [tr] th
end
)
)
local
fun map_intros f = TransferData.map
(fn {intros,unfolds,refolds,consts} =>
{intros=f intros, unfolds=unfolds, refolds=refolds, consts=consts})
fun map_unfolds f = TransferData.map
(fn {intros,unfolds,refolds,consts} =>
{intros=intros, unfolds=f unfolds, refolds=refolds, consts=consts})
fun map_refolds f = TransferData.map
(fn {intros,unfolds,refolds,consts} =>
{intros=intros, unfolds=unfolds, refolds=f refolds, consts=consts})
fun map_consts f = TransferData.map
(fn {intros,unfolds,refolds,consts} =>
{intros=intros, unfolds=unfolds, refolds=refolds, consts=f consts})
in
fun intro_add_global (thy, thm) = (map_intros (Drule.add_rule thm) thy, thm);
fun intro_del_global (thy, thm) = (map_intros (Drule.del_rule thm) thy, thm);
fun unfold_add_global (thy, thm) = (map_unfolds (Drule.add_rule thm) thy, thm);
fun unfold_del_global (thy, thm) = (map_unfolds (Drule.del_rule thm) thy, thm);
fun refold_add_global (thy, thm) = (map_refolds (Drule.add_rule thm) thy, thm);
fun refold_del_global (thy, thm) = (map_refolds (Drule.del_rule thm) thy, thm);
end
local
val undef_local =
Attrib.add_del_args
Attrib.undef_local_attribute
Attrib.undef_local_attribute;
in
val intro_attr =
(Attrib.add_del_args intro_add_global intro_del_global, undef_local);
val unfold_attr =
(Attrib.add_del_args unfold_add_global unfold_del_global, undef_local);
val refold_attr =
(Attrib.add_del_args refold_add_global refold_del_global, undef_local);
end
val transfer_method = Method.SIMPLE_METHOD' HEADGOAL o transfer_tac;
val setup =
[ TransferData.init
, Attrib.add_attributes
[ ("transfer_intro", intro_attr, "transfer introduction rule")
, ("transfer_unfold", unfold_attr, "transfer unfolding rule")
, ("transfer_refold", refold_attr, "transfer refolding rule")
]
, Method.add_method
("transfer", Method.thms_args transfer_method, "transfer principle")
];
end;