(* Title: Pure/Tools/class_package.ML
ID: $Id$
Author: Florian Haftmann, TU Muenchen
Type classes derived from primitive axclasses and locales.
*)
signature CLASS_PACKAGE =
sig
val class: bstring -> class list -> Element.context list -> theory
-> ProofContext.context * theory
val class_i: bstring -> class list -> Element.context_i list -> theory
-> ProofContext.context * theory
val instance_arity: (xstring * string list) * string
-> bstring * Attrib.src list -> ((bstring * Attrib.src list) * string) list
-> theory -> Proof.state
val instance_arity_i: (string * sort list) * sort
-> bstring * attribute list -> ((bstring * attribute list) * term) list
-> theory -> Proof.state
val prove_instance_arity: tactic -> (string * sort list) * sort
-> bstring * attribute list -> ((bstring * attribute list) * term) list
-> theory -> theory
val instance_sort: string * string -> theory -> Proof.state
val instance_sort_i: class * sort -> theory -> Proof.state
val prove_instance_sort: tactic -> class * sort -> theory -> theory
val intern_class: theory -> xstring -> class
val intern_sort: theory -> sort -> sort
val extern_class: theory -> class -> xstring
val extern_sort: theory -> sort -> sort
val certify_class: theory -> class -> class
val certify_sort: theory -> sort -> sort
val read_sort: theory -> string -> sort
val operational_sort_of: theory -> sort -> sort
val the_superclasses: theory -> class -> class list
val the_consts_sign: theory -> class -> string * (string * typ) list
val the_inst_sign: theory -> class * string -> (string * sort) list * (string * typ) list
val print_classes: theory -> unit
val intro_classes_tac: thm list -> tactic
val default_intro_classes_tac: thm list -> tactic
type sortcontext = (string * sort) list
datatype classlookup = Instance of (class * string) * classlookup list list
| Lookup of class list * (string * (int * int))
val sortcontext_of_typ: theory -> typ -> sortcontext
val sortlookup: theory -> sort * typ -> classlookup list
val sortlookups_const: theory -> string * typ -> classlookup list list
val use_instance2: bool ref;
val the_propnames: theory -> class -> string list
end;
structure ClassPackage: CLASS_PACKAGE =
struct
(* auxiliary *)
fun instantiations_of thy (ty, ty') =
let
val vartab = typ_tvars ty;
fun prep_vartab (v, (_, ty)) =
case (the o AList.lookup (op =) vartab) v
of [] => NONE
| sort => SOME ((v, sort), ty);
in case try (Sign.typ_match thy (ty, ty')) Vartab.empty
of NONE => NONE
| SOME vartab =>
SOME ((map_filter prep_vartab o Vartab.dest) vartab)
end;
(* theory data *)
datatype class_data = ClassData of {
name_locale: string,
name_axclass: string,
var: string,
consts: (string * (string * typ)) list,
(*locale parameter ~> toplevel constant*)
propnames: string list
} * thm list Symtab.table;
fun rep_classdata (ClassData c) = c;
structure ClassData = TheoryDataFun (
struct
val name = "Pure/classes";
type T = class_data Symtab.table;
val empty = Symtab.empty;
val copy = I;
val extend = I;
fun merge _ = Symtab.join (fn _ => fn (ClassData (classd, instd1), ClassData (_, instd2)) =>
(ClassData (classd, Symtab.merge (K true) (instd1, instd2))));
fun print thy data =
let
fun pretty_class (name, ClassData ({name_locale, name_axclass, var, consts, ...}, _)) =
(Pretty.block o Pretty.fbreaks) [
Pretty.str ("class " ^ name ^ ":"),
Pretty.str ("locale: " ^ name_locale),
Pretty.str ("axclass: " ^ name_axclass),
Pretty.str ("class variable: " ^ var),
(Pretty.block o Pretty.fbreaks) (
Pretty.str "constants: "
:: map (fn (_, (c, ty)) => Pretty.str (c ^ " :: " ^ Sign.string_of_typ thy ty)) consts
)
]
in
(Pretty.writeln o Pretty.chunks o map pretty_class o Symtab.dest) data
end;
end
);
val _ = Context.add_setup ClassData.init;
val print_classes = ClassData.print;
(* queries *)
val lookup_class_data = Option.map rep_classdata oo Symtab.lookup o ClassData.get;
fun the_class_data thy class =
case lookup_class_data thy class
of NONE => error ("undeclared operational class " ^ quote class)
| SOME data => data;
val is_class = is_some oo lookup_class_data;
fun is_operational_class thy cls =
lookup_class_data thy cls
|> Option.map (not o null o #consts o fst)
|> the_default false;
fun operational_sort_of thy =
let
fun get_sort class =
if is_operational_class thy class
then [class]
else operational_sort_of thy (Sign.super_classes thy class);
in Sign.certify_sort thy o maps get_sort end;
fun the_superclasses thy class =
if is_class thy class
then
Sign.super_classes thy class
|> operational_sort_of thy
else
error ("no class: " ^ class);
fun the_ancestry thy classes =
let
fun ancestry class anc =
anc
|> cons class
|> fold ancestry (the_superclasses thy class);
in fold ancestry classes [] end;
fun subst_clsvar v ty_subst =
map_type_tfree (fn u as (w, _) =>
if w = v then ty_subst else TFree u);
val the_parm_map = #consts o fst oo the_class_data;
fun the_consts_sign thy class =
let
val data = (fst o the_class_data thy) class
in (#var data, (map snd o #consts) data) end;
fun the_inst_sign thy (class, tyco) =
let
val _ = if is_operational_class thy class then () else error ("no operational class: " ^ class);
val asorts = Sign.arity_sorts thy tyco [class];
val (clsvar, const_sign) = the_consts_sign thy class;
fun add_var sort used =
let
val v = hd (Term.invent_names used "'a" 1)
in ((v, sort), v::used) end;
val (vsorts, _) =
[clsvar]
|> fold (fn (_, ty) => curry (gen_union (op =))
((map (fst o fst) o typ_tvars) ty @ (map fst o typ_tfrees) ty)) const_sign
|> fold_map add_var asorts;
val ty_inst = Type (tyco, map TFree vsorts);
val inst_signs = map (apsnd (subst_clsvar clsvar ty_inst)) const_sign;
in (vsorts, inst_signs) end;
val the_propnames = #propnames o fst oo the_class_data;
(* updaters *)
fun add_class_data (class, (name_locale, name_axclass, var, consts, propnames)) =
ClassData.map (
Symtab.update_new (class, ClassData ({
name_locale = name_locale,
name_axclass = name_axclass,
var = var,
consts = consts,
propnames = propnames}, Symtab.empty))
);
fun add_inst_def ((class, tyco), thm) =
ClassData.map (
Symtab.map_entry class (fn ClassData (classd, instd) =>
ClassData (classd, Symtab.insert_list eq_thm (tyco, thm) instd))
);
(* name handling *)
fun certify_class thy class =
(fn class => (the_class_data thy class; class)) (Sign.certify_class thy class);
fun certify_sort thy sort =
map (fn class => (the_class_data thy class; class)) (Sign.certify_sort thy sort);
fun intern_class thy =
certify_class thy o Sign.intern_class thy;
fun intern_sort thy =
certify_sort thy o Sign.intern_sort thy;
fun extern_class thy =
Sign.extern_class thy o certify_class thy;
fun extern_sort thy =
Sign.extern_sort thy o certify_sort thy;
fun read_sort thy =
certify_sort thy o Sign.read_sort thy;
(* tactics and methods *)
fun intro_classes_tac facts st =
(ALLGOALS (Method.insert_tac facts THEN'
REPEAT_ALL_NEW (resolve_tac (AxClass.class_intros (Thm.theory_of_thm st))))
THEN Tactic.distinct_subgoals_tac) st;
fun default_intro_classes_tac [] = intro_classes_tac []
| default_intro_classes_tac _ = Tactical.no_tac; (*no error message!*)
fun default_tac rules ctxt facts =
HEADGOAL (Method.some_rule_tac rules ctxt facts) ORELSE
default_intro_classes_tac facts;
val _ = Context.add_setup (Method.add_methods
[("intro_classes", Method.no_args (Method.METHOD intro_classes_tac),
"back-chain introduction rules of classes"),
("default", Method.thms_ctxt_args (Method.METHOD oo default_tac),
"apply some intro/elim rule")]);
(* axclass instances *)
local
fun gen_instance mk_prop add_thm after_qed inst thy =
thy
|> ProofContext.init
|> Proof.theorem_i PureThy.internalK NONE (after_qed oo (fold o fold) add_thm) NONE ("", [])
(map (fn t => (("", []), [(t, [])])) (mk_prop thy inst));
in
val axclass_instance_sort =
gen_instance (single oo (Logic.mk_classrel oo AxClass.read_classrel)) AxClass.add_classrel I;
val axclass_instance_arity =
gen_instance (Logic.mk_arities oo Sign.read_arity) AxClass.add_arity;
val axclass_instance_arity_i =
gen_instance (Logic.mk_arities oo Sign.cert_arity) AxClass.add_arity;
end;
(* classes and instances *)
local
fun add_axclass_i (name, supsort) params axs thy =
let
val (c, thy') = thy
|> AxClass.define_class_i (name, supsort) params axs;
val {intro, axioms, ...} = AxClass.get_definition thy' c;
in ((c, (intro, axioms)), thy') end;
fun prove_interpretation_i (prfx, atts) expr insts tac thy =
let
fun ad_hoc_term NONE = NONE
| ad_hoc_term (SOME (Const (c, ty))) =
let
val p = setmp show_types true (setmp show_sorts true (setmp print_mode [] (Sign.pretty_typ thy))) ty;
val s = c ^ "::" ^ Pretty.output p;
in SOME s end
| ad_hoc_term (SOME t) =
let
val p = setmp show_types true (setmp show_sorts true (setmp print_mode [] (Sign.pretty_term thy))) t;
val s = Pretty.output p;
in SOME s end;
in
thy
|> Locale.interpretation (prfx, atts) expr (map ad_hoc_term insts)
|> Proof.global_terminal_proof (Method.Basic (fn _ => Method.SIMPLE_METHOD tac), NONE)
|-> (fn _ => I)
end;
fun gen_class add_locale prep_class bname raw_supclasses raw_elems thy =
let
val supclasses = map (prep_class thy) raw_supclasses;
val supsort =
supclasses
|> map (#name_axclass o fst o the_class_data thy)
|> Sign.certify_sort thy
|> null ? K (Sign.defaultS thy);
val expr = (Locale.Merge o map (Locale.Locale o #name_locale o fst o the_class_data thy)) supclasses;
val mapp_sup = AList.make
(the o AList.lookup (op =) ((flat o map (the_parm_map thy) o the_ancestry thy) supclasses))
((map (fst o fst) o Locale.parameters_of_expr thy) expr);
fun extract_tyvar_consts thy name_locale =
let
fun extract_tyvar_name thy tys =
fold (curry add_typ_tfrees) tys []
|> (fn [(v, sort)] =>
if Sign.subsort thy (supsort, sort)
then v
else error ("illegal sort constraint on class type variable: " ^ Sign.string_of_sort thy sort)
| [] => error ("no class type variable")
| vs => error ("more than one type variable: " ^ (commas o map (Sign.string_of_typ thy o TFree)) vs))
val consts1 =
Locale.parameters_of thy name_locale
|> map (apsnd Syntax.unlocalize_mixfix)
val v = (extract_tyvar_name thy o map (snd o fst)) consts1;
val consts2 = map ((apfst o apsnd) (subst_clsvar v (TFree (v, [])))) consts1;
in (v, chop (length mapp_sup) consts2) end;
fun add_consts v raw_cs_sup raw_cs_this thy =
let
fun add_global_const ((c, ty), syn) thy =
thy
|> Sign.add_consts_i [(c, ty |> subst_clsvar v (TFree (v, Sign.defaultS thy)), syn)]
|> `(fn thy => (c, (Sign.intern_const thy c, ty)))
in
thy
|> fold_map add_global_const raw_cs_this
end;
fun extract_assumes thy name_locale cs_mapp =
let
val subst_assume =
map_aterms (fn Free (c, ty) => Const ((fst o the o AList.lookup (op =) cs_mapp) c, ty)
| t => t)
fun prep_asm ((name, atts), ts) =
((NameSpace.base name, map (Attrib.attribute thy) atts), map subst_assume ts)
in
(map prep_asm o Locale.local_asms_of thy) name_locale
end;
fun add_global_constraint v class (_, (c, ty)) thy =
thy
|> Sign.add_const_constraint_i (c, SOME (subst_clsvar v (TFree (v, [class])) ty));
fun mk_const thy class v (c, ty) =
Const (c, subst_clsvar v (TFree (v, [class])) ty);
in
thy
|> add_locale bname expr raw_elems
|-> (fn (name_locale, ctxt) =>
`(fn thy => extract_tyvar_consts thy name_locale)
#-> (fn (v, (raw_cs_sup, raw_cs_this)) =>
add_consts v raw_cs_sup raw_cs_this
#-> (fn mapp_this =>
`(fn thy => extract_assumes thy name_locale (mapp_sup @ mapp_this))
#-> (fn loc_axioms =>
add_axclass_i (bname, supsort) (map (fst o snd) mapp_this) loc_axioms
#-> (fn (name_axclass, (_, ax_axioms)) =>
fold (add_global_constraint v name_axclass) mapp_this
#> add_class_data (name_locale, (name_locale, name_axclass, v, mapp_this,
map (fst o fst) loc_axioms))
#> prove_interpretation_i (NameSpace.base name_locale, [])
(Locale.Locale name_locale) (map (SOME o mk_const thy name_axclass v) (map snd (mapp_sup @ mapp_this)))
((ALLGOALS o ProofContext.fact_tac) ax_axioms)
#> pair ctxt
)))))
end;
in
val class = gen_class (Locale.add_locale false) intern_class;
val class_i = gen_class (Locale.add_locale_i false) certify_class;
end; (* local *)
local
fun gen_read_def thy prep_att read_def tyco ((raw_name, raw_atts), raw_t) =
let
val (_, t) = read_def thy (raw_name, raw_t);
val ((c, ty), _) = Sign.cert_def (Sign.pp thy) t;
val atts = map (prep_att thy) raw_atts;
val name = case raw_name
of "" => Thm.def_name (NameSpace.base c ^ "_" ^ NameSpace.base tyco)
| _ => raw_name;
in (c, (Logic.varifyT ty, ((name, t), atts))) end;
fun read_def thy = gen_read_def thy Attrib.attribute read_axm;
fun read_def_i thy = gen_read_def thy (K I) (K I);
fun gen_instance_arity prep_arity prep_att read_def do_proof raw_arity (raw_name, raw_atts) raw_defs theory =
let
val pp = Sign.pp theory;
val arity as (tyco, asorts, sort) = prep_arity theory ((fn ((x, y), z) => (x, y, z)) raw_arity);
val ty_inst = Type (tyco, map2 (curry TVar o rpair 0) (Term.invent_names [] "'a" (length asorts)) asorts)
val name = case raw_name
of "" => Thm.def_name ((space_implode "_" o map NameSpace.base) sort ^ "_" ^ NameSpace.base tyco)
| _ => raw_name;
val atts = map (prep_att theory) raw_atts;
fun get_consts class =
let
val data = (fst o the_class_data theory) class;
fun defined c =
is_some (find_first (fn (_, { lhs = [ty], ...}) =>
Sign.typ_instance theory (ty, ty_inst) orelse Sign.typ_instance theory (ty_inst, ty))
(Defs.specifications_of (Theory.defs_of theory) c))
val subst_ty = map_type_tfree (fn (v, sort) =>
if #var data = v then ty_inst else TVar ((v, 0), sort));
in
(map_filter (fn (_, (c, ty)) =>
if defined c then NONE else SOME ((c, (class, subst_ty ty)))) o #consts) data
end;
val cs = (maps get_consts o the_ancestry theory) sort;
fun read_defs defs cs =
let
val thy_read = (Sign.primitive_arity (tyco, asorts, sort) o Theory.copy) theory;
fun read raw_def cs =
let
val (c, (ty, def)) = read_def thy_read tyco raw_def;
val (class, ty') = case AList.lookup (op =) cs c
of NONE => error ("superfluous definition for constant " ^ quote c)
| SOME class_ty => class_ty;
val def' = case instantiations_of thy_read (ty, ty')
of NONE => error ("superfluous definition for constant " ^
quote c ^ "::" ^ Sign.string_of_typ thy_read ty)
| SOME insttab =>
(apfst o apsnd o map_term_types)
(Logic.unvarifyT o Term.instantiateT insttab o Logic.varifyT) def
in ((class, def'), AList.delete (op =) c cs) end;
in fold_map read defs cs end;
val (defs, _) = read_defs raw_defs cs;
fun get_remove_contraint c thy =
let
val ty = Sign.the_const_constraint thy c;
in
thy
|> Sign.add_const_constraint_i (c, NONE)
|> pair (c, Logic.legacy_unvarifyT ty)
end;
fun add_defs defs thy =
thy
|> PureThy.add_defs_i true (map snd defs)
|-> (fn thms => pair (map fst defs ~~ thms));
fun register_def (class, thm) thy =
thy
|> add_inst_def ((class, tyco), thm);
fun note_all thy =
let
val thms = maps (fn class => Symtab.lookup_list
((snd o the_class_data thy) class) tyco) (the_ancestry thy sort);
in
thy
|> PureThy.note_thmss_i PureThy.internalK [((name, atts), [(thms, [])])]
|> snd
end;
fun after_qed cs thy =
thy
|> fold Sign.add_const_constraint_i (map (apsnd SOME) cs);
in
theory
|> fold_map get_remove_contraint (map fst cs)
||>> add_defs defs
|-> (fn (cs, def_thms) =>
fold register_def def_thms
#> note_all
#> do_proof (after_qed cs) arity)
end;
fun instance_arity' do_proof = gen_instance_arity Sign.read_arity Attrib.attribute
read_def do_proof;
fun instance_arity_i' do_proof = gen_instance_arity Sign.cert_arity (K I)
read_def_i do_proof;
fun tactic_proof tac after_qed arity = AxClass.prove_arity arity tac #> after_qed;
in
val instance_arity = instance_arity' axclass_instance_arity_i;
val instance_arity_i = instance_arity_i' axclass_instance_arity_i;
val prove_instance_arity = instance_arity_i' o tactic_proof;
end; (* local *)
local
fun add_interpretation_in (after_qed : theory -> theory) (name, expr) thy =
thy
|> Locale.interpretation_in_locale (name, expr);
fun prove_interpretation_in tac (after_qed : theory -> theory) (name, expr) thy =
thy
|> Locale.interpretation_in_locale (name, expr)
|> Proof.global_terminal_proof (Method.Basic (fn _ => Method.SIMPLE_METHOD tac), NONE)
|> snd
|> after_qed;
fun gen_instance_sort prep_class prep_sort do_proof (raw_class, raw_sort) theory =
let
val class = prep_class theory raw_class;
val sort = prep_sort theory raw_sort;
val loc_name = (#name_locale o fst o the_class_data theory) class;
val loc_expr =
(Locale.Merge o map (Locale.Locale o #name_locale o fst o the_class_data theory)) sort;
val const_names = (map (NameSpace.base o fst o snd)
o maps (#consts o fst o the_class_data theory)
o the_ancestry theory) [class];
val prop_tab = AList.make (the_propnames theory)
(the_ancestry theory sort);
fun mk_thm_names (superclass, prop_names) =
let
val thm_name_base = NameSpace.append "local" (space_implode "_" const_names);
val export_name = class ^ "_" ^ superclass;
in (export_name, map (Name o NameSpace.append thm_name_base) prop_names) end;
val notes_tab_proto = map mk_thm_names prop_tab;
fun test_note thy thmref =
can (Locale.note_thmss PureThy.corollaryK loc_name
[(("", []), [(thmref, [])])]) (Theory.copy thy);
val notes_tab = map_filter (fn (export_name, thm_names) => case filter (test_note theory) thm_names
of [] => NONE
| thm_names' => SOME (export_name, thm_names')) notes_tab_proto;
val _ = writeln ("fishing for ");
val _ = print notes_tab;
fun after_qed thy = thy;
fun after_qed''' thy =
fold (fn supclass =>
AxClass.prove_classrel (class, supclass)
(ALLGOALS (K (intro_classes_tac [])) THEN
(ALLGOALS o resolve_tac o flat) [])
) sort thy;
in
theory
|> do_proof after_qed (loc_name, loc_expr)
end;
fun instance_sort' do_proof = gen_instance_sort intern_class read_sort do_proof;
fun instance_sort_i' do_proof = gen_instance_sort certify_class certify_sort do_proof;
val setup_proof = add_interpretation_in;
val tactic_proof = prove_interpretation_in;
in
val instance_sort = instance_sort' setup_proof;
val instance_sort_i = instance_sort_i' setup_proof;
val prove_instance_sort = instance_sort_i' o tactic_proof;
end; (* local *)
(* extracting dictionary obligations from types *)
type sortcontext = (string * sort) list;
fun sortcontext_of_typ thy ty =
(typ_tfrees o fst o Type.freeze_thaw_type) ty
|> map (apsnd (operational_sort_of thy))
|> filter (not o null o snd);
datatype classlookup = Instance of (class * string) * classlookup list list
| Lookup of class list * (string * (int * int))
fun pretty_lookup' (Instance ((class, tyco), lss)) =
(Pretty.block o Pretty.breaks) (
Pretty.enum "," "{" "}" [Pretty.str class, Pretty.str tyco]
:: map pretty_lookup lss
)
| pretty_lookup' (Lookup (classes, (v, (i, j)))) =
Pretty.enum " <" "[" "]" (map Pretty.str classes @
[Pretty.str (v ^ "!" ^ string_of_int i ^ "/" ^ string_of_int j)])
and pretty_lookup ls = (Pretty.enum "," "(" ")" o map pretty_lookup') ls;
fun sortlookup thy (sort_decl, typ_ctxt) =
let
val pp = Sign.pp thy;
val algebra = Sorts.project_algebra pp (is_operational_class thy)
(Sign.classes_of thy);
fun classrel (l as Lookup (classes, p), _) class =
Lookup (class :: classes, p)
| classrel (Instance ((_, tyco), lss), _) class =
Instance ((class, tyco), lss);
fun constructor tyco lss class =
Instance ((class, tyco), (map o map) fst lss)
fun variable (TFree (v, sort)) =
map_index (fn (n, class) => (Lookup ([], (v, (n, length sort))), class))
(operational_sort_of thy sort)
| variable (TVar _) = error "TVar encountered while deriving sortlookup";
in
Sorts.of_sort_derivation pp algebra
{classrel = classrel, constructor = constructor, variable = variable}
(typ_ctxt, operational_sort_of thy sort_decl)
end;
fun sortlookups_const thy (c, typ_ctxt) =
let
val typ_decl = case AxClass.class_of thy c
of NONE => Sign.the_const_type thy c
| SOME class => case the_consts_sign thy class of (v, cs) =>
(Logic.legacy_varifyT o subst_clsvar v (TFree (v, [class])))
((the o AList.lookup (op =) cs) c)
in
instantiations_of thy (typ_decl, typ_ctxt)
|> the
|> map (fn ((_, sort), ty) => sortlookup thy (sort, ty))
|> filter_out null
end;
(* toplevel interface *)
local
structure P = OuterParse
and K = OuterKeyword
in
val (classK, instanceK) = ("class", "instance")
val use_instance2 = ref false;
fun wrap_add_instance_sort (class, sort) thy =
if ! use_instance2
andalso forall (is_some o lookup_class_data thy) (Sign.read_sort thy sort)
then
instance_sort (class, sort) thy
else
axclass_instance_sort (class, sort) thy
val parse_inst =
(Scan.optional (P.$$$ "(" |-- P.!!! (P.list1 P.sort --| P.$$$ ")")) [] -- P.xname --| P.$$$ "::" -- P.sort)
>> (fn ((asorts, tyco), sort) => ((tyco, asorts), sort))
|| (P.xname --| P.$$$ "::" -- P.!!! P.arity)
>> (fn (tyco, (asorts, sort)) => ((tyco, asorts), sort));
val locale_val =
(P.locale_expr --
Scan.optional (P.$$$ "+" |-- P.!!! (Scan.repeat1 P.context_element)) [] ||
Scan.repeat1 P.context_element >> pair Locale.empty);
val class_subP = P.name -- Scan.repeat (P.$$$ "+" |-- P.name) >> (op ::);
val class_bodyP = P.!!! (Scan.repeat1 P.context_element);
val classP =
OuterSyntax.command classK "operational type classes" K.thy_decl (
P.name --| P.$$$ "="
-- (
class_subP --| P.$$$ "+" -- class_bodyP
|| class_subP >> rpair []
|| class_bodyP >> pair []
) >> (Toplevel.theory_context
o (fn (bname, (supclasses, elems)) => class bname supclasses elems)));
val instanceP =
OuterSyntax.command instanceK "prove type arity or subclass relation" K.thy_goal ((
P.xname -- ((P.$$$ "\\<subseteq>" || P.$$$ "<") |-- P.!!! P.xname) >> wrap_add_instance_sort
|| P.opt_thm_name ":" -- (parse_inst -- Scan.repeat (P.opt_thm_name ":" -- P.prop))
>> (fn (("", []), (((tyco, asorts), sort), [])) => axclass_instance_arity I (tyco, asorts, sort)
| (natts, (inst, defs)) => instance_arity inst natts defs)
) >> (Toplevel.print oo Toplevel.theory_to_proof));
val _ = OuterSyntax.add_parsers [classP, instanceP];
end; (* local *)
end; (* struct *)