Simplified proof of induction rule for datatypes involving function types.
(* Title: HOL/Tools/datatype_rep_proofs.ML
ID: $Id$
Author: Stefan Berghofer, TU Muenchen
License: GPL (GNU GENERAL PUBLIC LICENSE)
Definitional introduction of datatypes
Proof of characteristic theorems:
- injectivity of constructors
- distinctness of constructors
- induction theorem
*)
signature DATATYPE_REP_PROOFS =
sig
val representation_proofs : bool -> DatatypeAux.datatype_info Symtab.table ->
string list -> (int * (string * DatatypeAux.dtyp list *
(string * DatatypeAux.dtyp list) list)) list list -> (string * sort) list ->
(string * mixfix) list -> (string * mixfix) list list -> theory attribute
-> theory -> theory * thm list list * thm list list * thm list list *
DatatypeAux.simproc_dist list * thm
end;
structure DatatypeRepProofs : DATATYPE_REP_PROOFS =
struct
open DatatypeAux;
val (_ $ (_ $ (_ $ (distinct_f $ _) $ _))) = hd (prems_of distinct_lemma);
(** theory context references **)
val f_myinv_f = thm "f_myinv_f";
val myinv_f_f = thm "myinv_f_f";
fun exh_thm_of (dt_info : datatype_info Symtab.table) tname =
#exhaustion (the (Symtab.lookup (dt_info, tname)));
(******************************************************************************)
fun representation_proofs flat_names (dt_info : datatype_info Symtab.table)
new_type_names descr sorts types_syntax constr_syntax case_names_induct thy =
let
val Datatype_thy =
if PureThy.get_name thy = "Datatype" then thy
else theory "Datatype";
val node_name = "Datatype_Universe.node";
val In0_name = "Datatype_Universe.In0";
val In1_name = "Datatype_Universe.In1";
val Scons_name = "Datatype_Universe.Scons";
val Leaf_name = "Datatype_Universe.Leaf";
val Numb_name = "Datatype_Universe.Numb";
val Lim_name = "Datatype_Universe.Lim";
val Funs_name = "Datatype_Universe.Funs";
val o_name = "Fun.op o";
val sum_case_name = "Datatype.sum.sum_case";
val [In0_inject, In1_inject, Scons_inject, Leaf_inject, In0_eq, In1_eq,
In0_not_In1, In1_not_In0, Funs_mono, FunsI, Lim_inject,
Funs_inv, FunsD, Funs_rangeE, Funs_nonempty, sum_case_inject] = map (get_thm Datatype_thy)
["In0_inject", "In1_inject", "Scons_inject", "Leaf_inject", "In0_eq", "In1_eq",
"In0_not_In1", "In1_not_In0", "Funs_mono", "FunsI", "Lim_inject",
"Funs_inv", "FunsD", "Funs_rangeE", "Funs_nonempty", "sum_case_inject"];
val Funs_IntE = (Int_lower2 RS Funs_mono RS
(Int_lower1 RS Funs_mono RS Int_greatest) RS subsetD) RS IntE;
val descr' = flat descr;
val big_name = space_implode "_" new_type_names;
val thy1 = add_path flat_names big_name thy;
val big_rec_name = big_name ^ "_rep_set";
val rep_set_names = map (Sign.full_name (Theory.sign_of thy1))
(if length descr' = 1 then [big_rec_name] else
(map ((curry (op ^) (big_rec_name ^ "_")) o string_of_int)
(1 upto (length descr'))));
val tyvars = map (fn (_, (_, Ts, _)) => map dest_DtTFree Ts) (hd descr);
val leafTs' = get_nonrec_types descr' sorts;
val branchTs = get_branching_types descr' sorts;
val branchT = if null branchTs then HOLogic.unitT
else fold_bal (fn (T, U) => Type ("+", [T, U])) branchTs;
val unneeded_vars = hd tyvars \\ foldr add_typ_tfree_names (leafTs' @ branchTs, []);
val leafTs = leafTs' @ (map (fn n => TFree (n, the (assoc (sorts, n)))) unneeded_vars);
val recTs = get_rec_types descr' sorts;
val newTs = take (length (hd descr), recTs);
val oldTs = drop (length (hd descr), recTs);
val sumT = if null leafTs then HOLogic.unitT
else fold_bal (fn (T, U) => Type ("+", [T, U])) leafTs;
val Univ_elT = HOLogic.mk_setT (Type (node_name, [sumT, branchT]));
val UnivT = HOLogic.mk_setT Univ_elT;
val In0 = Const (In0_name, Univ_elT --> Univ_elT);
val In1 = Const (In1_name, Univ_elT --> Univ_elT);
val Leaf = Const (Leaf_name, sumT --> Univ_elT);
val Lim = Const (Lim_name, (branchT --> Univ_elT) --> Univ_elT);
(* make injections needed for embedding types in leaves *)
fun mk_inj T' x =
let
fun mk_inj' T n i =
if n = 1 then x else
let val n2 = n div 2;
val Type (_, [T1, T2]) = T
in
if i <= n2 then
Const ("Inl", T1 --> T) $ (mk_inj' T1 n2 i)
else
Const ("Inr", T2 --> T) $ (mk_inj' T2 (n - n2) (i - n2))
end
in mk_inj' sumT (length leafTs) (1 + find_index_eq T' leafTs)
end;
(* make injections for constructors *)
fun mk_univ_inj ts = access_bal (fn t => In0 $ t, fn t => In1 $ t, if ts = [] then
Const ("arbitrary", Univ_elT)
else
foldr1 (HOLogic.mk_binop Scons_name) ts);
(* function spaces *)
fun mk_fun_inj T' x =
let
fun mk_inj T n i =
if n = 1 then x else
let
val n2 = n div 2;
val Type (_, [T1, T2]) = T;
val sum_case = Const (sum_case_name, [T1 --> Univ_elT, T2 --> Univ_elT, T] ---> Univ_elT)
in
if i <= n2 then
sum_case $ (mk_inj T1 n2 i) $ Const ("arbitrary", T2 --> Univ_elT)
else
sum_case $ Const ("arbitrary", T1 --> Univ_elT) $ mk_inj T2 (n - n2) (i - n2)
end
in mk_inj branchT (length branchTs) (1 + find_index_eq T' branchTs)
end;
(************** generate introduction rules for representing set **********)
val _ = message "Constructing representing sets ...";
(* make introduction rule for a single constructor *)
fun make_intr s n (i, (_, cargs)) =
let
fun mk_prem (DtRec k, (j, prems, ts)) =
let val free_t = mk_Free "x" Univ_elT j
in (j + 1, (HOLogic.mk_mem (free_t,
Const (nth_elem (k, rep_set_names), UnivT)))::prems, free_t::ts)
end
| mk_prem (DtType ("fun", [T, DtRec k]), (j, prems, ts)) =
let val T' = typ_of_dtyp descr' sorts T;
val free_t = mk_Free "x" (T' --> Univ_elT) j
in (j + 1, (HOLogic.mk_mem (free_t,
Const (Funs_name, UnivT --> HOLogic.mk_setT (T' --> Univ_elT)) $
Const (nth_elem (k, rep_set_names), UnivT)))::prems,
Lim $ mk_fun_inj T' free_t::ts)
end
| mk_prem (dt, (j, prems, ts)) =
let val T = typ_of_dtyp descr' sorts dt
in (j + 1, prems, (Leaf $ mk_inj T (mk_Free "x" T j))::ts)
end;
val (_, prems, ts) = foldr mk_prem (cargs, (1, [], []));
val concl = HOLogic.mk_Trueprop (HOLogic.mk_mem
(mk_univ_inj ts n i, Const (s, UnivT)))
in Logic.list_implies (map HOLogic.mk_Trueprop prems, concl)
end;
val consts = map (fn s => Const (s, UnivT)) rep_set_names;
val intr_ts = flat (map (fn ((_, (_, _, constrs)), rep_set_name) =>
map (make_intr rep_set_name (length constrs))
((1 upto (length constrs)) ~~ constrs)) (descr' ~~ rep_set_names));
val (thy2, {raw_induct = rep_induct, intrs = rep_intrs, ...}) =
setmp InductivePackage.quiet_mode (!quiet_mode)
(InductivePackage.add_inductive_i false true big_rec_name false true false
consts (map (fn x => (("", x), [])) intr_ts) [Funs_mono]) thy1;
(********************************* typedef ********************************)
val thy3 = add_path flat_names big_name (foldl (fn (thy, ((((name, mx), tvs), c), name')) =>
setmp TypedefPackage.quiet_mode true
(TypedefPackage.add_typedef_i false (Some name') (name, tvs, mx) c None
(rtac exI 1 THEN
QUIET_BREADTH_FIRST (has_fewer_prems 1)
(resolve_tac (Funs_nonempty::rep_intrs) 1))) thy |> #1)
(parent_path flat_names thy2, types_syntax ~~ tyvars ~~
(take (length newTs, consts)) ~~ new_type_names));
(*********************** definition of constructors ***********************)
val big_rep_name = (space_implode "_" new_type_names) ^ "_Rep_";
val rep_names = map (curry op ^ "Rep_") new_type_names;
val rep_names' = map (fn i => big_rep_name ^ (string_of_int i))
(1 upto (length (flat (tl descr))));
val all_rep_names = map (Sign.intern_const (Theory.sign_of thy3)) rep_names @
map (Sign.full_name (Theory.sign_of thy3)) rep_names';
(* isomorphism declarations *)
val iso_decls = map (fn (T, s) => (s, T --> Univ_elT, NoSyn))
(oldTs ~~ rep_names');
(* constructor definitions *)
fun make_constr_def tname T n ((thy, defs, eqns, i), ((cname, cargs), (cname', mx))) =
let
fun constr_arg (dt, (j, l_args, r_args)) =
let val T = typ_of_dtyp descr' sorts dt;
val free_t = mk_Free "x" T j
in (case dt of
DtRec m => (j + 1, free_t::l_args, (Const (nth_elem (m, all_rep_names),
T --> Univ_elT) $ free_t)::r_args)
| DtType ("fun", [T', DtRec m]) =>
let val ([T''], T''') = strip_type T
in (j + 1, free_t::l_args, (Lim $ mk_fun_inj T''
(Const (o_name, [T''' --> Univ_elT, T, T''] ---> Univ_elT) $
Const (nth_elem (m, all_rep_names), T''' --> Univ_elT) $ free_t))::r_args)
end
| _ => (j + 1, free_t::l_args, (Leaf $ mk_inj T free_t)::r_args))
end;
val (_, l_args, r_args) = foldr constr_arg (cargs, (1, [], []));
val constrT = (map (typ_of_dtyp descr' sorts) cargs) ---> T;
val abs_name = Sign.intern_const (Theory.sign_of thy) ("Abs_" ^ tname);
val rep_name = Sign.intern_const (Theory.sign_of thy) ("Rep_" ^ tname);
val lhs = list_comb (Const (cname, constrT), l_args);
val rhs = mk_univ_inj r_args n i;
val def = equals T $ lhs $ (Const (abs_name, Univ_elT --> T) $ rhs);
val def_name = (Sign.base_name cname) ^ "_def";
val eqn = HOLogic.mk_Trueprop (HOLogic.mk_eq
(Const (rep_name, T --> Univ_elT) $ lhs, rhs));
val (thy', [def_thm]) = thy |>
Theory.add_consts_i [(cname', constrT, mx)] |>
(PureThy.add_defs_i false o map Thm.no_attributes) [(def_name, def)];
in (thy', defs @ [def_thm], eqns @ [eqn], i + 1) end;
(* constructor definitions for datatype *)
fun dt_constr_defs ((thy, defs, eqns, rep_congs, dist_lemmas),
((((_, (_, _, constrs)), tname), T), constr_syntax)) =
let
val _ $ (_ $ (cong_f $ _) $ _) = concl_of arg_cong;
val sg = Theory.sign_of thy;
val rep_const = cterm_of sg
(Const (Sign.intern_const sg ("Rep_" ^ tname), T --> Univ_elT));
val cong' = standard (cterm_instantiate [(cterm_of sg cong_f, rep_const)] arg_cong);
val dist = standard (cterm_instantiate [(cterm_of sg distinct_f, rep_const)] distinct_lemma);
val (thy', defs', eqns', _) = foldl ((make_constr_def tname T) (length constrs))
((add_path flat_names tname thy, defs, [], 1), constrs ~~ constr_syntax)
in
(parent_path flat_names thy', defs', eqns @ [eqns'],
rep_congs @ [cong'], dist_lemmas @ [dist])
end;
val (thy4, constr_defs, constr_rep_eqns, rep_congs, dist_lemmas) = foldl dt_constr_defs
((thy3 |> Theory.add_consts_i iso_decls |> parent_path flat_names, [], [], [], []),
hd descr ~~ new_type_names ~~ newTs ~~ constr_syntax);
(*********** isomorphisms for new types (introduced by typedef) ***********)
val _ = message "Proving isomorphism properties ...";
(* get axioms from theory *)
val newT_iso_axms = map (fn s =>
(get_thm thy4 ("Abs_" ^ s ^ "_inverse"),
get_thm thy4 ("Rep_" ^ s ^ "_inverse"),
get_thm thy4 ("Rep_" ^ s))) new_type_names;
(*------------------------------------------------*)
(* prove additional theorems: *)
(* inj_on dt_Abs_i rep_set_i and inj dt_Rep_i *)
(*------------------------------------------------*)
fun prove_newT_iso_inj_thm (((s, (thm1, thm2, _)), T), rep_set_name) =
let
val sg = Theory.sign_of thy4;
val RepT = T --> Univ_elT;
val Rep_name = Sign.intern_const sg ("Rep_" ^ s);
val AbsT = Univ_elT --> T;
val Abs_name = Sign.intern_const sg ("Abs_" ^ s);
val inj_Abs_thm =
prove_goalw_cterm []
(cterm_of sg
(HOLogic.mk_Trueprop
(Const ("Fun.inj_on", [AbsT, UnivT] ---> HOLogic.boolT) $
Const (Abs_name, AbsT) $ Const (rep_set_name, UnivT))))
(fn _ => [rtac inj_on_inverseI 1, etac thm1 1]);
val setT = HOLogic.mk_setT T
val inj_Rep_thm =
prove_goalw_cterm []
(cterm_of sg
(HOLogic.mk_Trueprop
(Const ("Fun.inj_on", [RepT, setT] ---> HOLogic.boolT) $
Const (Rep_name, RepT) $ Const ("UNIV", setT))))
(fn _ => [rtac inj_inverseI 1, rtac thm2 1])
in (inj_Abs_thm, inj_Rep_thm) end;
val newT_iso_inj_thms = map prove_newT_iso_inj_thm
(new_type_names ~~ newT_iso_axms ~~ newTs ~~
take (length newTs, rep_set_names));
(********* isomorphisms between existing types and "unfolded" types *******)
(*---------------------------------------------------------------------*)
(* isomorphisms are defined using primrec-combinators: *)
(* generate appropriate functions for instantiating primrec-combinator *)
(* *)
(* e.g. dt_Rep_i = list_rec ... (%h t y. In1 ((Leaf h) $ y)) *)
(* *)
(* also generate characteristic equations for isomorphisms *)
(* *)
(* e.g. dt_Rep_i (cons h t) = In1 ((dt_Rep_j h) $ (dt_Rep_i t)) *)
(*---------------------------------------------------------------------*)
fun make_iso_def k ks n ((fs, eqns, i), (cname, cargs)) =
let
val argTs = map (typ_of_dtyp descr' sorts) cargs;
val T = nth_elem (k, recTs);
val rep_name = nth_elem (k, all_rep_names);
val rep_const = Const (rep_name, T --> Univ_elT);
val constr = Const (cname, argTs ---> T);
fun process_arg ks' ((i2, i2', ts, Ts), dt) =
let val T' = typ_of_dtyp descr' sorts dt
in (case dt of
DtRec j => if j mem ks' then
(i2 + 1, i2' + 1, ts @ [mk_Free "y" Univ_elT i2'], Ts @ [Univ_elT])
else
(i2 + 1, i2', ts @ [Const (nth_elem (j, all_rep_names),
T' --> Univ_elT) $ mk_Free "x" T' i2], Ts)
| (DtType ("fun", [_, DtRec j])) =>
let val ([T''], T''') = strip_type T'
in if j mem ks' then
(i2 + 1, i2' + 1, ts @ [Lim $ mk_fun_inj T''
(mk_Free "y" (T'' --> Univ_elT) i2')], Ts @ [T'' --> Univ_elT])
else
(i2 + 1, i2', ts @ [Lim $ mk_fun_inj T''
(Const (o_name, [T''' --> Univ_elT, T', T''] ---> Univ_elT) $
Const (nth_elem (j, all_rep_names), T''' --> Univ_elT) $
mk_Free "x" T' i2)], Ts)
end
| _ => (i2 + 1, i2', ts @ [Leaf $ mk_inj T' (mk_Free "x" T' i2)], Ts))
end;
val (i2, i2', ts, Ts) = foldl (process_arg ks) ((1, 1, [], []), cargs);
val xs = map (uncurry (mk_Free "x")) (argTs ~~ (1 upto (i2 - 1)));
val ys = map (uncurry (mk_Free "y")) (Ts ~~ (1 upto (i2' - 1)));
val f = list_abs_free (map dest_Free (xs @ ys), mk_univ_inj ts n i);
val (_, _, ts', _) = foldl (process_arg []) ((1, 1, [], []), cargs);
val eqn = HOLogic.mk_Trueprop (HOLogic.mk_eq
(rep_const $ list_comb (constr, xs), mk_univ_inj ts' n i))
in (fs @ [f], eqns @ [eqn], i + 1) end;
(* define isomorphisms for all mutually recursive datatypes in list ds *)
fun make_iso_defs (ds, (thy, char_thms)) =
let
val ks = map fst ds;
val (_, (tname, _, _)) = hd ds;
val {rec_rewrites, rec_names, ...} = the (Symtab.lookup (dt_info, tname));
fun process_dt ((fs, eqns, isos), (k, (tname, _, constrs))) =
let
val (fs', eqns', _) = foldl (make_iso_def k ks (length constrs))
((fs, eqns, 1), constrs);
val iso = (nth_elem (k, recTs), nth_elem (k, all_rep_names))
in (fs', eqns', isos @ [iso]) end;
val (fs, eqns, isos) = foldl process_dt (([], [], []), ds);
val fTs = map fastype_of fs;
val defs = map (fn (rec_name, (T, iso_name)) => ((Sign.base_name iso_name) ^ "_def",
equals (T --> Univ_elT) $ Const (iso_name, T --> Univ_elT) $
list_comb (Const (rec_name, fTs @ [T] ---> Univ_elT), fs))) (rec_names ~~ isos);
val (thy', def_thms) = (PureThy.add_defs_i false o map Thm.no_attributes) defs thy;
(* prove characteristic equations *)
val rewrites = def_thms @ (map mk_meta_eq rec_rewrites);
val char_thms' = map (fn eqn => prove_goalw_cterm rewrites
(cterm_of (Theory.sign_of thy') eqn) (fn _ => [rtac refl 1])) eqns;
in (thy', char_thms' @ char_thms) end;
val (thy5, iso_char_thms) = foldr make_iso_defs
(tl descr, (add_path flat_names big_name thy4, []));
(* prove isomorphism properties *)
fun mk_funs_inv thm =
let
val [_, t] = prems_of Funs_inv;
val [_ $ (_ $ _ $ R)] = Logic.strip_assums_hyp t;
val _ $ (_ $ (r $ (a $ _)) $ _) = Logic.strip_assums_concl t;
val [_ $ (_ $ _ $ R')] = prems_of thm;
val _ $ (_ $ (r' $ (a' $ _)) $ _) = concl_of thm;
val inv' = cterm_instantiate (map
((pairself (cterm_of (sign_of_thm thm))) o
(apsnd (map_term_types (incr_tvar 1))))
[(R, R'), (r, r'), (a, a')]) Funs_inv
in
rule_by_tactic (atac 2) (thm RSN (2, inv'))
end;
(* prove inj dt_Rep_i and dt_Rep_i x : dt_rep_set_i *)
fun prove_iso_thms (ds, (inj_thms, elem_thms)) =
let
val (_, (tname, _, _)) = hd ds;
val {induction, ...} = the (Symtab.lookup (dt_info, tname));
fun mk_ind_concl (i, _) =
let
val T = nth_elem (i, recTs);
val Rep_t = Const (nth_elem (i, all_rep_names), T --> Univ_elT);
val rep_set_name = nth_elem (i, rep_set_names)
in (HOLogic.all_const T $ Abs ("y", T, HOLogic.imp $
HOLogic.mk_eq (Rep_t $ mk_Free "x" T i, Rep_t $ Bound 0) $
HOLogic.mk_eq (mk_Free "x" T i, Bound 0)),
HOLogic.mk_mem (Rep_t $ mk_Free "x" T i, Const (rep_set_name, UnivT)))
end;
val (ind_concl1, ind_concl2) = ListPair.unzip (map mk_ind_concl ds);
val rewrites = map mk_meta_eq iso_char_thms;
val inj_thms' = flat (map (fn r => [r RS injD, r RS inj_o])
(map snd newT_iso_inj_thms @ inj_thms));
val inj_thm = prove_goalw_cterm [] (cterm_of (Theory.sign_of thy5)
(HOLogic.mk_Trueprop (mk_conj ind_concl1))) (fn _ =>
[(indtac induction THEN_ALL_NEW ObjectLogic.atomize_tac) 1,
REPEAT (EVERY
[rtac allI 1, rtac impI 1,
exh_tac (exh_thm_of dt_info) 1,
REPEAT (EVERY
[hyp_subst_tac 1,
rewrite_goals_tac rewrites,
REPEAT (dresolve_tac [In0_inject, In1_inject] 1),
(eresolve_tac [In0_not_In1 RS notE, In1_not_In0 RS notE] 1)
ORELSE (EVERY
[REPEAT (eresolve_tac (Scons_inject :: sum_case_inject ::
map make_elim (inj_thms' @
[Leaf_inject, Lim_inject, Inl_inject, Inr_inject])) 1),
REPEAT ((EVERY [etac allE 1, dtac mp 1, atac 1]) ORELSE
(dtac inj_fun_lemma 1 THEN atac 1)),
REPEAT (hyp_subst_tac 1),
rtac refl 1])])])]);
val inj_thms'' = map (fn r => r RS datatype_injI)
(split_conj_thm inj_thm);
val elem_thm =
prove_goalw_cterm []
(cterm_of (Theory.sign_of thy5)
(HOLogic.mk_Trueprop (mk_conj ind_concl2)))
(fn _ =>
[(indtac induction THEN_ALL_NEW ObjectLogic.atomize_tac) 1,
rewrite_goals_tac (o_def :: rewrites),
REPEAT (EVERY
[resolve_tac rep_intrs 1,
REPEAT (FIRST [atac 1, etac spec 1,
resolve_tac (FunsI :: elem_thms) 1])])]);
in (inj_thms'' @ inj_thms, elem_thms @ (split_conj_thm elem_thm))
end;
val (iso_inj_thms_unfolded, iso_elem_thms) = foldr prove_iso_thms
(tl descr, ([], map #3 newT_iso_axms));
val iso_inj_thms = map snd newT_iso_inj_thms @ iso_inj_thms_unfolded;
(* prove x : dt_rep_set_i --> x : range dt_Rep_i *)
fun mk_iso_t (((set_name, iso_name), i), T) =
let val isoT = T --> Univ_elT
in HOLogic.imp $
HOLogic.mk_mem (mk_Free "x" Univ_elT i, Const (set_name, UnivT)) $
(if i < length newTs then Const ("True", HOLogic.boolT)
else HOLogic.mk_mem (mk_Free "x" Univ_elT i,
Const ("image", [isoT, HOLogic.mk_setT T] ---> UnivT) $
Const (iso_name, isoT) $ Const ("UNIV", HOLogic.mk_setT T)))
end;
val iso_t = HOLogic.mk_Trueprop (mk_conj (map mk_iso_t
(rep_set_names ~~ all_rep_names ~~ (0 upto (length descr' - 1)) ~~ recTs)));
(* all the theorems are proved by one single simultaneous induction *)
val iso_thms = if length descr = 1 then [] else
drop (length newTs, split_conj_thm
(prove_goalw_cterm [] (cterm_of (Theory.sign_of thy5) iso_t) (fn _ =>
[indtac rep_induct 1,
REPEAT (rtac TrueI 1),
REPEAT (EVERY
[rewrite_goals_tac [mk_meta_eq Collect_mem_eq],
REPEAT (etac Funs_IntE 1),
REPEAT (eresolve_tac (rangeE ::
map (fn r => r RS Funs_rangeE) iso_inj_thms_unfolded) 1),
REPEAT (eresolve_tac (map (fn (iso, _, _) => iso RS subst) newT_iso_axms @
map (fn (iso, _, _) => mk_funs_inv iso RS subst) newT_iso_axms) 1),
TRY (hyp_subst_tac 1),
rtac (sym RS range_eqI) 1,
resolve_tac iso_char_thms 1])])));
val Abs_inverse_thms' =
map #1 newT_iso_axms @
map2 (fn (r_inj, r) => f_myinv_f OF [r_inj, r RS mp])
(iso_inj_thms_unfolded, iso_thms);
val Abs_inverse_thms = map (fn r => r RS subst) (Abs_inverse_thms' @
map mk_funs_inv Abs_inverse_thms');
(******************* freeness theorems for constructors *******************)
val _ = message "Proving freeness of constructors ...";
(* prove theorem Rep_i (Constr_j ...) = Inj_j ... *)
fun prove_constr_rep_thm eqn =
let
val inj_thms = map (fn (r, _) => r RS inj_onD) newT_iso_inj_thms;
val rewrites = o_def :: constr_defs @ (map (mk_meta_eq o #2) newT_iso_axms)
in prove_goalw_cterm [] (cterm_of (Theory.sign_of thy5) eqn) (fn _ =>
[resolve_tac inj_thms 1,
rewrite_goals_tac rewrites,
rtac refl 1,
resolve_tac rep_intrs 2,
REPEAT (resolve_tac (FunsI :: iso_elem_thms) 1)])
end;
(*--------------------------------------------------------------*)
(* constr_rep_thms and rep_congs are used to prove distinctness *)
(* of constructors. *)
(*--------------------------------------------------------------*)
val constr_rep_thms = map (map prove_constr_rep_thm) constr_rep_eqns;
val dist_rewrites = map (fn (rep_thms, dist_lemma) =>
dist_lemma::(rep_thms @ [In0_eq, In1_eq, In0_not_In1, In1_not_In0]))
(constr_rep_thms ~~ dist_lemmas);
fun prove_distinct_thms (_, []) = []
| prove_distinct_thms (dist_rewrites', t::_::ts) =
let
val dist_thm = prove_goalw_cterm [] (cterm_of (Theory.sign_of thy5) t) (fn _ =>
[simp_tac (HOL_ss addsimps dist_rewrites') 1])
in dist_thm::(standard (dist_thm RS not_sym))::
(prove_distinct_thms (dist_rewrites', ts))
end;
val distinct_thms = map prove_distinct_thms (dist_rewrites ~~
DatatypeProp.make_distincts new_type_names descr sorts thy5);
val simproc_dists = map (fn ((((_, (_, _, constrs)), rep_thms), congr), dists) =>
if length constrs < !DatatypeProp.dtK then FewConstrs dists
else ManyConstrs (congr, HOL_basic_ss addsimps rep_thms)) (hd descr ~~
constr_rep_thms ~~ rep_congs ~~ distinct_thms);
(* prove injectivity of constructors *)
fun prove_constr_inj_thm rep_thms t =
let val inj_thms = Scons_inject::sum_case_inject::(map make_elim
((map (fn r => r RS injD) iso_inj_thms) @
[In0_inject, In1_inject, Leaf_inject, Inl_inject, Inr_inject, Lim_inject]))
in prove_goalw_cterm [] (cterm_of (Theory.sign_of thy5) t) (fn _ =>
[rtac iffI 1,
REPEAT (etac conjE 2), hyp_subst_tac 2, rtac refl 2,
dresolve_tac rep_congs 1, dtac box_equals 1,
REPEAT (resolve_tac rep_thms 1), rewtac o_def,
REPEAT (eresolve_tac inj_thms 1),
REPEAT (ares_tac [conjI] 1 ORELSE (EVERY [rtac ext 1, dtac fun_cong 1,
eresolve_tac inj_thms 1, atac 1]))])
end;
val constr_inject = map (fn (ts, thms) => map (prove_constr_inj_thm thms) ts)
((DatatypeProp.make_injs descr sorts) ~~ constr_rep_thms);
val (thy6, (constr_inject', distinct_thms'))= thy5 |> parent_path flat_names |>
store_thmss "inject" new_type_names constr_inject |>>>
store_thmss "distinct" new_type_names distinct_thms;
(*************************** induction theorem ****************************)
val _ = message "Proving induction rule for datatypes ...";
val Rep_inverse_thms = (map (fn (_, iso, _) => iso RS subst) newT_iso_axms) @
(map (fn r => r RS myinv_f_f RS subst) iso_inj_thms_unfolded);
val Rep_inverse_thms' = map (fn r => r RS myinv_f_f) iso_inj_thms_unfolded;
fun mk_indrule_lemma ((prems, concls), ((i, _), T)) =
let
val Rep_t = Const (nth_elem (i, all_rep_names), T --> Univ_elT) $
mk_Free "x" T i;
val Abs_t = if i < length newTs then
Const (Sign.intern_const (Theory.sign_of thy6)
("Abs_" ^ (nth_elem (i, new_type_names))), Univ_elT --> T)
else Const ("Inductive.myinv", [T --> Univ_elT, Univ_elT] ---> T) $
Const (nth_elem (i, all_rep_names), T --> Univ_elT)
in (prems @ [HOLogic.imp $ HOLogic.mk_mem (Rep_t,
Const (nth_elem (i, rep_set_names), UnivT)) $
(mk_Free "P" (T --> HOLogic.boolT) (i + 1) $ (Abs_t $ Rep_t))],
concls @ [mk_Free "P" (T --> HOLogic.boolT) (i + 1) $ mk_Free "x" T i])
end;
val (indrule_lemma_prems, indrule_lemma_concls) =
foldl mk_indrule_lemma (([], []), (descr' ~~ recTs));
val cert = cterm_of (Theory.sign_of thy6);
val indrule_lemma = prove_goalw_cterm [] (cert
(Logic.mk_implies
(HOLogic.mk_Trueprop (mk_conj indrule_lemma_prems),
HOLogic.mk_Trueprop (mk_conj indrule_lemma_concls)))) (fn prems =>
[cut_facts_tac prems 1, REPEAT (etac conjE 1),
REPEAT (EVERY
[TRY (rtac conjI 1), resolve_tac Rep_inverse_thms 1,
etac mp 1, resolve_tac iso_elem_thms 1])]);
val Ps = map head_of (HOLogic.dest_conj (HOLogic.dest_Trueprop (concl_of indrule_lemma)));
val frees = if length Ps = 1 then [Free ("P", snd (dest_Var (hd Ps)))] else
map (Free o apfst fst o dest_Var) Ps;
val indrule_lemma' = cterm_instantiate (map cert Ps ~~ map cert frees) indrule_lemma;
val dt_induct = prove_goalw_cterm [] (cert
(DatatypeProp.make_ind descr sorts)) (fn prems =>
[rtac indrule_lemma' 1, indtac rep_induct 1,
EVERY (map (fn (prem, r) => (EVERY
[REPEAT (eresolve_tac (Funs_IntE::Abs_inverse_thms) 1),
simp_tac (HOL_basic_ss addsimps ((symmetric r)::Rep_inverse_thms')) 1,
DEPTH_SOLVE_1 (ares_tac [prem] 1 ORELSE (EVERY [rewtac o_def,
dtac FunsD 1, etac CollectD 1]))]))
(prems ~~ (constr_defs @ (map mk_meta_eq iso_char_thms))))]);
val (thy7, [dt_induct']) = thy6 |>
Theory.add_path big_name |>
PureThy.add_thms [(("induct", dt_induct), [case_names_induct])] |>>
Theory.parent_path;
in (thy7, constr_inject', distinct_thms', dist_rewrites, simproc_dists, dt_induct')
end;
end;