(* Title: HOL/Tools/datatype_abs_proofs.ML
ID: $Id$
Author: Stefan Berghofer
Copyright 1998 TU Muenchen
Proofs and defintions independent of concrete representation
of datatypes (i.e. requiring only abstract properties such as
injectivity / distinctness of constructors and induction)
- case distinction (exhaustion) theorems
- characteristic equations for primrec combinators
- characteristic equations for case combinators
- distinctness of constructors (external version)
- equations for splitting "P (case ...)" expressions
- datatype size function
- "nchotomy" and "case_cong" theorems for TFL
*)
signature DATATYPE_ABS_PROOFS =
sig
val prove_casedist_thms : string list -> (int * (string * DatatypeAux.dtyp list *
(string * DatatypeAux.dtyp list) list)) list list -> (string * sort) list ->
thm -> theory -> theory * thm list
val prove_primrec_thms : string list -> (int * (string * DatatypeAux.dtyp list *
(string * DatatypeAux.dtyp list) list)) list list -> (string * sort) list ->
DatatypeAux.datatype_info Symtab.table -> thm list list -> thm list list ->
thm -> theory -> theory * string list * thm list
val prove_case_thms : string list -> (int * (string * DatatypeAux.dtyp list *
(string * DatatypeAux.dtyp list) list)) list list -> (string * sort) list ->
string list -> thm list -> theory -> theory * string list * thm list list
val prove_distinctness_thms : string list -> (int * (string * DatatypeAux.dtyp list *
(string * DatatypeAux.dtyp list) list)) list list -> (string * sort) list ->
thm list list -> thm list list -> theory -> theory * thm list list
val prove_split_thms : string list -> (int * (string * DatatypeAux.dtyp list *
(string * DatatypeAux.dtyp list) list)) list list -> (string * sort) list ->
thm list list -> thm list list -> thm list -> thm list list -> theory ->
theory * (thm * thm) list
val prove_size_thms : string list -> (int * (string * DatatypeAux.dtyp list *
(string * DatatypeAux.dtyp list) list)) list list -> (string * sort) list ->
string list -> thm list -> theory -> theory * thm list
val prove_nchotomys : string list -> (int * (string * DatatypeAux.dtyp list *
(string * DatatypeAux.dtyp list) list)) list list -> (string * sort) list ->
thm list -> theory -> theory * thm list
val prove_case_congs : string list -> (int * (string * DatatypeAux.dtyp list *
(string * DatatypeAux.dtyp list) list)) list list -> (string * sort) list ->
thm list -> thm list list -> theory -> theory * thm list
end;
structure DatatypeAbsProofs : DATATYPE_ABS_PROOFS =
struct
open DatatypeAux;
val thin = read_instantiate_sg (sign_of Set.thy) [("V", "?X : ?Y")] thin_rl;
val (_ $ (_ $ (_ $ (distinct_f $ _) $ _))) = hd (prems_of distinct_lemma);
(************************ case distinction theorems ***************************)
fun prove_casedist_thms new_type_names descr sorts induct thy =
let
val _ = writeln "Proving case distinction theorems...";
val descr' = flat descr;
val recTs = get_rec_types descr' sorts;
val newTs = take (length (hd descr), recTs);
val induct_Ps = map head_of (dest_conj (HOLogic.dest_Trueprop (concl_of induct)));
fun prove_casedist_thm ((i, t), T) =
let
val dummyPs = map (fn (Var (_, Type (_, [T', T'']))) =>
Abs ("z", T', Const ("True", T''))) induct_Ps;
val P = Abs ("z", T, HOLogic.imp $ HOLogic.mk_eq (Var (("a", 0), T), Bound 0) $
Var (("P", 0), HOLogic.boolT))
val insts = take (i, dummyPs) @ (P::(drop (i + 1, dummyPs)));
val cert = cterm_of (sign_of thy);
val insts' = (map cert induct_Ps) ~~ (map cert insts);
val induct' = refl RS ((nth_elem (i,
split_conj_thm (cterm_instantiate insts' induct))) RSN (2, rev_mp))
in prove_goalw_cterm [] (cert t) (fn prems =>
[rtac induct' 1,
REPEAT (rtac TrueI 1),
REPEAT ((rtac impI 1) THEN (eresolve_tac prems 1)),
REPEAT (rtac TrueI 1)])
end;
val casedist_thms = map prove_casedist_thm ((0 upto (length newTs - 1)) ~~
(DatatypeProp.make_casedists descr sorts) ~~ newTs)
in
(store_thms "exhaust" new_type_names casedist_thms thy, casedist_thms)
end;
(*************************** primrec combinators ******************************)
fun prove_primrec_thms new_type_names descr sorts
(dt_info : datatype_info Symtab.table) constr_inject dist_rewrites induct thy =
let
val _ = writeln "Constructing primrec combinators...";
val descr' = flat descr;
val recTs = get_rec_types descr' sorts;
val newTs = take (length (hd descr), recTs);
val induct_Ps = map head_of (dest_conj (HOLogic.dest_Trueprop (concl_of induct)));
val big_rec_name' = (space_implode "_" new_type_names) ^ "_rec_set";
val rec_set_names = map (Sign.full_name (sign_of thy))
(if length descr' = 1 then [big_rec_name'] else
(map ((curry (op ^) (big_rec_name' ^ "_")) o string_of_int)
(1 upto (length descr'))));
val rec_result_Ts = map (fn (i, _) =>
TFree ("'t" ^ (string_of_int (i + 1)), HOLogic.termS)) descr';
val reccomb_fn_Ts = flat (map (fn (i, (_, _, constrs)) =>
map (fn (_, cargs) =>
let
val recs = filter is_rec_type cargs;
val argTs = (map (typ_of_dtyp descr' sorts) cargs) @
(map (fn r => nth_elem (dest_DtRec r, rec_result_Ts)) recs)
in argTs ---> nth_elem (i, rec_result_Ts)
end) constrs) descr');
val rec_set_Ts = map (fn (T1, T2) => reccomb_fn_Ts ---> HOLogic.mk_setT
(HOLogic.mk_prodT (T1, T2))) (recTs ~~ rec_result_Ts);
val rec_fns = map (uncurry (mk_Free "f"))
(reccomb_fn_Ts ~~ (1 upto (length reccomb_fn_Ts)));
val rec_sets = map (fn c => list_comb (Const c, rec_fns))
(rec_set_names ~~ rec_set_Ts);
(* introduction rules for graph of primrec function *)
fun make_rec_intr T set_name ((rec_intr_ts, l), (cname, cargs)) =
let
fun mk_prem (dt, (j, k, prems, t1s, t2s)) =
let
val T = typ_of_dtyp descr' sorts dt;
val free1 = mk_Free "x" T j
in (case dt of
DtRec m =>
let val free2 = mk_Free "y" (nth_elem (m, rec_result_Ts)) k
in (j + 1, k + 1, (HOLogic.mk_Trueprop (HOLogic.mk_mem
(HOLogic.mk_prod (free1, free2), nth_elem (m, rec_sets))))::prems,
free1::t1s, free2::t2s)
end
| _ => (j + 1, k, prems, free1::t1s, t2s))
end;
val Ts = map (typ_of_dtyp descr' sorts) cargs;
val (_, _, prems, t1s, t2s) = foldr mk_prem (cargs, (1, 1, [], [], []))
in (rec_intr_ts @ [Logic.list_implies (prems, HOLogic.mk_Trueprop (HOLogic.mk_mem
(HOLogic.mk_prod (list_comb (Const (cname, Ts ---> T), t1s),
list_comb (nth_elem (l, rec_fns), t1s @ t2s)), set_name)))], l + 1)
end;
val (rec_intr_ts, _) = foldl (fn (x, ((d, T), set_name)) =>
foldl (make_rec_intr T set_name) (x, #3 (snd d)))
(([], 0), descr' ~~ recTs ~~ rec_sets);
val (thy1, {intrs = rec_intrs, elims = rec_elims, ...}) =
InductivePackage.add_inductive_i false true big_rec_name' false false true
rec_sets rec_intr_ts [] [] thy;
(* prove uniqueness and termination of primrec combinators *)
val _ = writeln "Proving termination and uniqueness of primrec functions...";
fun mk_unique_tac ((tac, intrs), ((((i, (tname, _, constrs)), elim), T), T')) =
let
val distinct_tac = (etac Pair_inject 1) THEN
(if i < length newTs then
full_simp_tac (HOL_ss addsimps (nth_elem (i, dist_rewrites))) 1
else full_simp_tac (HOL_ss addsimps
((#distinct (the (Symtab.lookup (dt_info, tname)))) @
[Suc_Suc_eq, Suc_not_Zero, Zero_not_Suc])) 1);
val inject = map (fn r => r RS iffD1)
(if i < length newTs then nth_elem (i, constr_inject)
else #inject (the (Symtab.lookup (dt_info, tname))));
fun mk_unique_constr_tac n ((tac, intr::intrs, j), (cname, cargs)) =
let
val k = length (filter is_rec_type cargs)
in (EVERY [DETERM tac,
REPEAT (etac ex1E 1), rtac ex1I 1,
DEPTH_SOLVE_1 (ares_tac [intr] 1),
REPEAT_DETERM_N k (etac thin 1),
etac elim 1,
REPEAT_DETERM_N j distinct_tac,
etac Pair_inject 1, TRY (dresolve_tac inject 1),
REPEAT (etac conjE 1), hyp_subst_tac 1,
REPEAT (etac allE 1),
REPEAT (dtac mp 1 THEN atac 1),
TRY (hyp_subst_tac 1),
rtac refl 1,
REPEAT_DETERM_N (n - j - 1) distinct_tac],
intrs, j + 1)
end;
val (tac', intrs', _) = foldl (mk_unique_constr_tac (length constrs))
((tac, intrs, 0), constrs);
in (tac', intrs') end;
val rec_unique_thms =
let
val rec_unique_ts = map (fn (((set_t, T1), T2), i) =>
Const ("Ex1", (T2 --> HOLogic.boolT) --> HOLogic.boolT) $
absfree ("y", T2, HOLogic.mk_mem (HOLogic.mk_prod
(mk_Free "x" T1 i, Free ("y", T2)), set_t)))
(rec_sets ~~ recTs ~~ rec_result_Ts ~~ (1 upto length recTs));
val cert = cterm_of (sign_of thy1)
val insts = map (fn ((i, T), t) => absfree ("x" ^ (string_of_int i), T, t))
((1 upto length recTs) ~~ recTs ~~ rec_unique_ts);
val induct' = cterm_instantiate ((map cert induct_Ps) ~~
(map cert insts)) induct;
val (tac, _) = foldl mk_unique_tac
((rtac induct' 1, rec_intrs), descr' ~~ rec_elims ~~ recTs ~~ rec_result_Ts)
in split_conj_thm (prove_goalw_cterm []
(cert (HOLogic.mk_Trueprop (mk_conj rec_unique_ts))) (K [tac]))
end;
val rec_total_thms = map (fn r =>
r RS ex1_implies_ex RS (select_eq_Ex RS iffD2)) rec_unique_thms;
(* define primrec combinators *)
val big_reccomb_name = (space_implode "_" new_type_names) ^ "_rec";
val reccomb_names = map (Sign.full_name (sign_of thy1))
(if length descr' = 1 then [big_reccomb_name] else
(map ((curry (op ^) (big_reccomb_name ^ "_")) o string_of_int)
(1 upto (length descr'))));
val reccombs = map (fn ((name, T), T') => list_comb
(Const (name, reccomb_fn_Ts @ [T] ---> T'), rec_fns))
(reccomb_names ~~ recTs ~~ rec_result_Ts);
val thy2 = thy1 |>
Theory.add_consts_i (map (fn ((name, T), T') =>
(Sign.base_name name, reccomb_fn_Ts @ [T] ---> T', NoSyn))
(reccomb_names ~~ recTs ~~ rec_result_Ts)) |>
Theory.add_defs_i (map (fn ((((name, comb), set), T), T') =>
((Sign.base_name name) ^ "_def", Logic.mk_equals
(comb $ Free ("x", T),
Const ("Eps", (T' --> HOLogic.boolT) --> T') $ absfree ("y", T',
HOLogic.mk_mem (HOLogic.mk_prod (Free ("x", T), Free ("y", T')), set)))))
(reccomb_names ~~ reccombs ~~ rec_sets ~~ recTs ~~ rec_result_Ts));
val reccomb_defs = map ((get_def thy2) o Sign.base_name) reccomb_names;
(* prove characteristic equations for primrec combinators *)
val _ = writeln "Proving characteristic theorems for primrec combinators..."
val rec_thms = map (fn t => prove_goalw_cterm reccomb_defs
(cterm_of (sign_of thy2) t) (fn _ =>
[rtac select1_equality 1,
resolve_tac rec_unique_thms 1,
resolve_tac rec_intrs 1,
REPEAT (resolve_tac rec_total_thms 1)]))
(DatatypeProp.make_primrecs new_type_names descr sorts thy2)
in
(PureThy.add_tthmss [(("recs", map Attribute.tthm_of rec_thms), [])] thy2,
reccomb_names, rec_thms)
end;
(***************************** case combinators *******************************)
fun prove_case_thms new_type_names descr sorts reccomb_names primrec_thms thy =
let
val _ = writeln "Proving characteristic theorems for case combinators...";
val descr' = flat descr;
val recTs = get_rec_types descr' sorts;
val newTs = take (length (hd descr), recTs);
val case_dummy_fns = map (fn (_, (_, _, constrs)) => map (fn (_, cargs) =>
let
val Ts = map (typ_of_dtyp descr' sorts) cargs;
val free = TFree ("'t", HOLogic.termS);
val Ts' = replicate (length (filter is_rec_type cargs)) free
in Const ("arbitrary", Ts @ Ts' ---> free)
end) constrs) descr';
val case_names = map (fn s =>
Sign.full_name (sign_of thy) (s ^ "_case")) new_type_names;
(* define case combinators via primrec combinators *)
val (case_defs, thy2) = foldl (fn ((defs, thy),
((((i, (_, _, constrs)), T), name), recname)) =>
let
val T' = TFree ("'t", HOLogic.termS);
val (fns1, fns2) = ListPair.unzip (map (fn ((_, cargs), j) =>
let
val Ts = map (typ_of_dtyp descr' sorts) cargs;
val Ts' = Ts @ (replicate (length (filter is_rec_type cargs)) T');
val frees' = map (uncurry (mk_Free "x")) (Ts' ~~ (1 upto length Ts'));
val frees = take (length cargs, frees');
val free = mk_Free "f" (Ts ---> T') j
in
(free, list_abs_free (map dest_Free frees',
list_comb (free, frees)))
end) (constrs ~~ (1 upto length constrs)));
val caseT = (map (snd o dest_Free) fns1) @ [T] ---> T';
val fns = (flat (take (i, case_dummy_fns))) @
fns2 @ (flat (drop (i + 1, case_dummy_fns)));
val reccomb = Const (recname, (map fastype_of fns) @ [T] ---> T');
val decl = (Sign.base_name name, caseT, NoSyn);
val def = ((Sign.base_name name) ^ "_def",
Logic.mk_equals (list_comb (Const (name, caseT), fns1),
list_comb (reccomb, (flat (take (i, case_dummy_fns))) @
fns2 @ (flat (drop (i + 1, case_dummy_fns))) )));
val thy' = thy |>
Theory.add_consts_i [decl] |> Theory.add_defs_i [def];
in (defs @ [get_def thy' (Sign.base_name name)], thy')
end) (([], thy), (hd descr) ~~ newTs ~~ case_names ~~
(take (length newTs, reccomb_names)));
val case_thms = map (map (fn t => prove_goalw_cterm (case_defs @
(map mk_meta_eq primrec_thms)) (cterm_of (sign_of thy2) t)
(fn _ => [rtac refl 1])))
(DatatypeProp.make_cases new_type_names descr sorts thy2);
val thy3 = Theory.add_trrules_i
(DatatypeProp.make_case_trrules new_type_names descr) thy2
in (store_thmss "cases" new_type_names case_thms thy3, case_names, case_thms)
end;
(************************ distinctness of constructors ************************)
fun prove_distinctness_thms new_type_names descr sorts dist_rewrites case_thms thy =
let
val descr' = flat descr;
val recTs = get_rec_types descr' sorts;
val newTs = take (length (hd descr), recTs);
(*--------------------------------------------------------------------*)
(* define t_ord - functions for proving distinctness of constructors: *)
(* t_ord C_i ... = i *)
(*--------------------------------------------------------------------*)
fun define_ord ((thy, ord_defs), (((_, (_, _, constrs)), T), tname)) =
if length constrs < DatatypeProp.dtK then (thy, ord_defs)
else
let
val Tss = map ((map (typ_of_dtyp descr' sorts)) o snd) constrs;
val ts = map HOLogic.mk_nat (0 upto length constrs - 1);
val mk_abs = foldr (fn (T, t') => Abs ("x", T, t'));
val fs = map mk_abs (Tss ~~ ts);
val fTs = map (fn Ts => Ts ---> HOLogic.natT) Tss;
val ord_name = Sign.full_name (sign_of thy) (tname ^ "_ord");
val case_name = Sign.intern_const (sign_of thy) (tname ^ "_case");
val ordT = T --> HOLogic.natT;
val caseT = fTs ---> ordT;
val defpair = (tname ^ "_ord_def", Logic.mk_equals
(Const (ord_name, ordT), list_comb (Const (case_name, caseT), fs)));
val thy' = thy |>
Theory.add_consts_i [(tname ^ "_ord", ordT, NoSyn)] |>
Theory.add_defs_i [defpair];
val def = get_def thy' (tname ^ "_ord")
in (thy', ord_defs @ [def]) end;
val (thy2, ord_defs) =
foldl define_ord ((thy, []), (hd descr) ~~ newTs ~~ new_type_names);
(**** number of constructors < dtK ****)
fun prove_distinct_thms _ [] = []
| prove_distinct_thms dist_rewrites' (t::_::ts) =
let
val dist_thm = prove_goalw_cterm [] (cterm_of (sign_of thy2) 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 (fn ((((_, (_, _, constrs)), ts),
dist_rewrites'), case_thms) =>
if length constrs < DatatypeProp.dtK then
prove_distinct_thms dist_rewrites' ts
else
let
val t::ts' = rev ts;
val (_ $ (_ $ (_ $ (f $ _) $ _))) = hd (Logic.strip_imp_prems t);
val cert = cterm_of (sign_of thy2);
val distinct_lemma' = cterm_instantiate
[(cert distinct_f, cert f)] distinct_lemma;
val rewrites = ord_defs @ (map mk_meta_eq case_thms)
in
(map (fn t => prove_goalw_cterm rewrites (cert t)
(fn _ => [rtac refl 1])) (rev ts')) @ [standard distinct_lemma']
end) ((hd descr) ~~ (DatatypeProp.make_distincts new_type_names
descr sorts thy2) ~~ dist_rewrites ~~ case_thms)
in (store_thmss "distinct" new_type_names distinct_thms thy2, distinct_thms)
end;
(******************************* case splitting *******************************)
fun prove_split_thms new_type_names descr sorts constr_inject dist_rewrites
casedist_thms case_thms thy =
let
val _ = writeln "Proving equations for case splitting...";
val descr' = flat descr;
val recTs = get_rec_types descr' sorts;
val newTs = take (length (hd descr), recTs);
fun prove_split_thms ((((((t1, t2), inject), dist_rewrites'),
exhaustion), case_thms'), T) =
let
val cert = cterm_of (sign_of thy);
val _ $ (_ $ lhs $ _) = hd (Logic.strip_assums_hyp (hd (prems_of exhaustion)));
val exhaustion' = cterm_instantiate
[(cert lhs, cert (Free ("x", T)))] exhaustion;
val tacsf = K [rtac exhaustion' 1, ALLGOALS (asm_simp_tac
(HOL_ss addsimps (dist_rewrites' @ inject @ case_thms')))]
in
(prove_goalw_cterm [] (cert t1) tacsf,
prove_goalw_cterm [] (cert t2) tacsf)
end;
val split_thm_pairs = map prove_split_thms
((DatatypeProp.make_splits new_type_names descr sorts thy) ~~ constr_inject ~~
dist_rewrites ~~ casedist_thms ~~ case_thms ~~ newTs);
val (split_thms, split_asm_thms) = ListPair.unzip split_thm_pairs
in
(thy |> store_thms "split" new_type_names split_thms |>
store_thms "split_asm" new_type_names split_asm_thms,
split_thm_pairs)
end;
(******************************* size functions *******************************)
fun prove_size_thms new_type_names descr sorts reccomb_names primrec_thms thy =
let
val _ = writeln "Proving equations for size function...";
val descr' = flat descr;
val recTs = get_rec_types descr' sorts;
val big_size_name = space_implode "_" new_type_names ^ "_size";
val size_name = Sign.intern_const (sign_of (the (get_thy "Arith" thy))) "size";
val size_names = replicate (length (hd descr)) size_name @
map (Sign.full_name (sign_of thy))
(if length (flat (tl descr)) = 1 then [big_size_name] else
map (fn i => big_size_name ^ "_" ^ string_of_int i)
(1 upto length (flat (tl descr))));
val def_names = map (fn i => big_size_name ^ "_def_" ^ string_of_int i)
(1 upto length recTs);
val plus_t = Const ("op +", [HOLogic.natT, HOLogic.natT] ---> HOLogic.natT);
fun make_sizefun (_, cargs) =
let
val Ts = map (typ_of_dtyp descr' sorts) cargs;
val k = length (filter is_rec_type cargs);
val t = if k = 0 then HOLogic.zero else
foldl1 (app plus_t) (map Bound (k - 1 downto 0) @ [HOLogic.mk_nat 1])
in
foldr (fn (T, t') => Abs ("x", T, t')) (Ts @ replicate k HOLogic.natT, t)
end;
val fs = flat (map (fn (_, (_, _, constrs)) => map make_sizefun constrs) descr');
val fTs = map fastype_of fs;
val thy' = thy |>
Theory.add_consts_i (map (fn (s, T) =>
(Sign.base_name s, T --> HOLogic.natT, NoSyn))
(drop (length (hd descr), size_names ~~ recTs))) |>
Theory.add_defs_i (map (fn (((s, T), def_name), rec_name) =>
(def_name, Logic.mk_equals (Const (s, T --> HOLogic.natT),
list_comb (Const (rec_name, fTs @ [T] ---> HOLogic.natT), fs))))
(size_names ~~ recTs ~~ def_names ~~ reccomb_names));
val size_def_thms = map (get_axiom thy') def_names;
val rewrites = size_def_thms @ map mk_meta_eq primrec_thms;
val size_thms = map (fn t => prove_goalw_cterm rewrites
(cterm_of (sign_of thy') t) (fn _ => [rtac refl 1]))
(DatatypeProp.make_size new_type_names descr sorts thy')
in
(PureThy.add_tthmss [(("size", map Attribute.tthm_of size_thms), [])] thy',
size_thms)
end;
(************************* additional theorems for TFL ************************)
fun prove_nchotomys new_type_names descr sorts casedist_thms thy =
let
val _ = writeln "Proving additional theorems for TFL...";
fun prove_nchotomy (t, exhaustion) =
let
(* For goal i, select the correct disjunct to attack, then prove it *)
fun tac i 0 = EVERY [TRY (rtac disjI1 i),
hyp_subst_tac i, REPEAT (rtac exI i), rtac refl i]
| tac i n = rtac disjI2 i THEN tac i (n - 1)
in
prove_goalw_cterm [] (cterm_of (sign_of thy) t) (fn _ =>
[rtac allI 1,
exh_tac (K exhaustion) 1,
ALLGOALS (fn i => tac i (i-1))])
end;
val nchotomys =
map prove_nchotomy (DatatypeProp.make_nchotomys descr sorts ~~ casedist_thms)
in
(store_thms "nchotomy" new_type_names nchotomys thy, nchotomys)
end;
fun prove_case_congs new_type_names descr sorts nchotomys case_thms thy =
let
fun prove_case_cong ((t, nchotomy), case_rewrites) =
let
val (Const ("==>", _) $ tm $ _) = t;
val (Const ("Trueprop", _) $ (Const ("op =", _) $ _ $ Ma)) = tm;
val cert = cterm_of (sign_of thy);
val nchotomy' = nchotomy RS spec;
val nchotomy'' = cterm_instantiate
[(cert (hd (add_term_vars (concl_of nchotomy', []))), cert Ma)] nchotomy'
in
prove_goalw_cterm [] (cert t) (fn prems =>
let val simplify = asm_simp_tac (HOL_ss addsimps (prems @ case_rewrites))
in [simp_tac (HOL_ss addsimps [hd prems]) 1,
cut_facts_tac [nchotomy''] 1,
REPEAT (etac disjE 1 THEN REPEAT (etac exE 1) THEN simplify 1),
REPEAT (etac exE 1) THEN simplify 1 (* Get last disjunct *)]
end)
end;
val case_congs = map prove_case_cong (DatatypeProp.make_case_congs
new_type_names descr sorts thy ~~ nchotomys ~~ case_thms)
in
(store_thms "case_cong" new_type_names case_congs thy, case_congs)
end;
end;