(*  Title:      Tools/code/code_thingol.ML

     ID:         $Id$

     Author:     Florian Haftmann, TU Muenchen

 Intermediate language ("Thin-gol") representing executable code.

 Representation and translation.

 *)

 infix 8 `%%;

 infix 4 `$;

 infix 4 `$$;

 infixr 3 `|->;

 infixr 3 `|-->;

 signature BASIC_CODE_THINGOL =

 sig

   type vname = string;

   datatype dict =

       DictConst of string * dict list list

     | DictVar of string list * (vname * (int * int));

   datatype itype =

       `%% of string * itype list

     | ITyVar of vname;

   type const = string * (dict list list * itype list (*types of arguments*))

   datatype iterm =

       IConst of const

     | IVar of vname

     | `$ of iterm * iterm

     | `|-> of (vname * itype) * iterm

     | ICase of ((iterm * itype) * (iterm * iterm) list) * iterm;

         (*((term, type), [(selector pattern, body term )]), primitive term)*)

   val `$$ : iterm * iterm list -> iterm;

   val `|--> : (vname * itype) list * iterm -> iterm;

   type typscheme = (vname * sort) list * itype;

 end;

 signature CODE_THINGOL =

 sig

   include BASIC_CODE_THINGOL

   val unfoldl: ('a -> ('a * 'b) option) -> 'a -> 'a * 'b list

   val unfoldr: ('a -> ('b * 'a) option) -> 'a -> 'b list * 'a

   val unfold_fun: itype -> itype list * itype

   val unfold_app: iterm -> iterm * iterm list

   val split_abs: iterm -> (((vname * iterm option) * itype) * iterm) option

   val unfold_abs: iterm -> ((vname * iterm option) * itype) list * iterm

   val split_let: iterm -> (((iterm * itype) * iterm) * iterm) option

   val unfold_let: iterm -> ((iterm * itype) * iterm) list * iterm

   val unfold_const_app: iterm ->

     ((string * (dict list list * itype list)) * iterm list) option

   val collapse_let: ((vname * itype) * iterm) * iterm

     -> (iterm * itype) * (iterm * iterm) list

   val eta_expand: int -> (string * (dict list list * itype list)) * iterm list -> iterm

   val contains_dictvar: iterm -> bool

   val locally_monomorphic: iterm -> bool

   val fold_constnames: (string -> 'a -> 'a) -> iterm -> 'a -> 'a

   val fold_varnames: (string -> 'a -> 'a) -> iterm -> 'a -> 'a

   val fold_unbound_varnames: (string -> 'a -> 'a) -> iterm -> 'a -> 'a

   type naming

   val empty_naming: naming

   val lookup_class: naming -> class -> string option

   val lookup_classrel: naming -> class * class -> string option

   val lookup_tyco: naming -> string -> string option

   val lookup_instance: naming -> class * string -> string option

   val lookup_const: naming -> string -> string option

   datatype stmt =

       NoStmt

     | Fun of string * (typscheme * ((iterm list * iterm) * (thm * bool)) list)

     | Datatype of string * ((vname * sort) list * (string * itype list) list)

     | Datatypecons of string * string

     | Class of class * (vname * ((class * string) list * (string * itype) list))

     | Classrel of class * class

     | Classparam of string * class

     | Classinst of (class * (string * (vname * sort) list))

           * ((class * (string * (string * dict list list))) list

         * ((string * const) * (thm * bool)) list)

   type program = stmt Graph.T

   val empty_funs: program -> string list

   val map_terms_bottom_up: (iterm -> iterm) -> iterm -> iterm

   val map_terms_stmt: (iterm -> iterm) -> stmt -> stmt

   val is_cons: program -> string -> bool

   val contr_classparam_typs: program -> string -> itype option list

   val consts_program: theory -> string list -> string list * (naming * program)

   val cached_program: theory -> naming * program

   val eval_conv: theory

     -> (term -> term * (naming -> program -> typscheme * iterm -> string list -> thm))

     -> cterm -> thm

   val eval_term: theory

     -> (term -> term * (naming -> program -> typscheme * iterm -> string list -> 'a))

     -> term -> 'a

 end;

 structure Code_Thingol: CODE_THINGOL =

 struct

 (** auxiliary **)

 fun unfoldl dest x =

   case dest x

    of NONE => (x, [])

     | SOME (x1, x2) =>

         let val (x', xs') = unfoldl dest x1 in (x', xs' @ [x2]) end;

 fun unfoldr dest x =

   case dest x

    of NONE => ([], x)

     | SOME (x1, x2) =>

         let val (xs', x') = unfoldr dest x2 in (x1::xs', x') end;

 (** language core - types, patterns, expressions **)

 type vname = string;

 datatype dict =

     DictConst of string * dict list list

   | DictVar of string list * (vname * (int * int));

 datatype itype =

     `%% of string * itype list

   | ITyVar of vname;

 type const = string * (dict list list * itype list (*types of arguments*))

 datatype iterm =

     IConst of const

   | IVar of vname

   | `$ of iterm * iterm

   | `|-> of (vname * itype) * iterm

   | ICase of ((iterm * itype) * (iterm * iterm) list) * iterm;

     (*see also signature*)

 (*

   variable naming conventions

   bare names:

     variable names          v

     class names             class

     type constructor names  tyco

     datatype names          dtco

     const names (general)   c (const)

     constructor names       co

     class parameter names   classparam

     arbitrary name          s

     v, c, co, classparam also annotated with types etc.

   constructs:

     sort                    sort

     type parameters         vs

     type                    ty

     type schemes            tysm

     term                    t

     (term as pattern)       p

     instance (class, tyco)  inst

  *)

 val op `$$ = Library.foldl (op `$);

 val op `|--> = Library.foldr (op `|->);

 val unfold_app = unfoldl

   (fn op `$ t => SOME t

     | _ => NONE);

 val split_abs =

   (fn (v, ty) `|-> (t as ICase (((IVar w, _), [(p, t')]), _)) =>

         if v = w then SOME (((v, SOME p), ty), t') else SOME (((v, NONE), ty), t)

     | (v, ty) `|-> t => SOME (((v, NONE), ty), t)

     | _ => NONE);

 val unfold_abs = unfoldr split_abs;

 val split_let = 

   (fn ICase (((td, ty), [(p, t)]), _) => SOME (((p, ty), td), t)

     | _ => NONE);

 val unfold_let = unfoldr split_let;

 fun unfold_const_app t =

  case unfold_app t

   of (IConst c, ts) => SOME (c, ts)

    | _ => NONE;

 fun fold_aiterms f (t as IConst _) = f t

   | fold_aiterms f (t as IVar _) = f t

   | fold_aiterms f (t1 `$ t2) = fold_aiterms f t1 #> fold_aiterms f t2

   | fold_aiterms f (t as _ `|-> t') = f t #> fold_aiterms f t'

   | fold_aiterms f (ICase (_, t)) = fold_aiterms f t;

 fun fold_constnames f =

   let

     fun add (IConst (c, _)) = f c

       | add _ = I;

   in fold_aiterms add end;

 fun fold_varnames f =

   let

     fun add (IVar v) = f v

       | add ((v, _) `|-> _) = f v

       | add _ = I;

   in fold_aiterms add end;

 fun fold_unbound_varnames f =

   let

     fun add _ (IConst _) = I

       | add vs (IVar v) = if not (member (op =) vs v) then f v else I

       | add vs (t1 `$ t2) = add vs t1 #> add vs t2

       | add vs ((v, _) `|-> t) = add (insert (op =) v vs) t

       | add vs (ICase (_, t)) = add vs t;

   in add [] end;

 fun collapse_let (((v, ty), se), be as ICase (((IVar w, _), ds), _)) =

       let

         fun exists_v t = fold_unbound_varnames (fn w => fn b =>

           b orelse v = w) t false;

       in if v = w andalso forall (fn (t1, t2) =>

         exists_v t1 orelse not (exists_v t2)) ds

         then ((se, ty), ds)

         else ((se, ty), [(IVar v, be)])

       end

   | collapse_let (((v, ty), se), be) =

       ((se, ty), [(IVar v, be)])

 fun eta_expand k (c as (_, (_, tys)), ts) =

   let

     val j = length ts;

     val l = k - j;

     val ctxt = (fold o fold_varnames) Name.declare ts Name.context;

     val vs_tys = Name.names ctxt "a" ((curry Library.take l o curry Library.drop j) tys);

   in vs_tys `|--> IConst c `$$ ts @ map (fn (v, _) => IVar v) vs_tys end;

 fun contains_dictvar t =

   let

     fun contains (DictConst (_, dss)) = (fold o fold) contains dss

       | contains (DictVar _) = K true;

   in

     fold_aiterms

       (fn IConst (_, (dss, _)) => (fold o fold) contains dss | _ => I) t false

   end;

 fun locally_monomorphic (IConst _) = false

   | locally_monomorphic (IVar _) = true

   | locally_monomorphic (t `$ _) = locally_monomorphic t

   | locally_monomorphic (_ `|-> t) = locally_monomorphic t

   | locally_monomorphic (ICase ((_, ds), _)) = exists (locally_monomorphic o snd) ds;

 (** namings **)

 (* policies *)

 local

   fun thyname_of thy f x = the (AList.lookup (op =) (f x) Markup.theory_nameN);

   fun thyname_of_class thy =

     thyname_of thy (ProofContext.query_class (ProofContext.init thy));

   fun thyname_of_tyco thy =

     thyname_of thy (Type.the_tags (Sign.tsig_of thy));

   fun thyname_of_instance thy inst = case AxClass.arity_property thy inst Markup.theory_nameN

    of [] => error ("no such instance: " ^ quote (snd inst ^ " :: " ^ fst inst))

     | thyname :: _ => thyname;

   fun thyname_of_const thy c = case AxClass.class_of_param thy c

    of SOME class => thyname_of_class thy class

     | NONE => (case Code.get_datatype_of_constr thy c

        of SOME dtco => thyname_of_tyco thy dtco

         | NONE => thyname_of thy (Consts.the_tags (Sign.consts_of thy)) c);

   fun namify thy get_basename get_thyname name =

     let

       val prefix = get_thyname thy name;

       val base = (Code_Name.purify_base true o get_basename) name;

     in NameSpace.append prefix base end;

 in

 fun namify_class thy = namify thy NameSpace.base thyname_of_class;

 fun namify_classrel thy = namify thy (fn (class1, class2) => 

   NameSpace.base class2 ^ "_" ^ NameSpace.base class1) (fn thy => thyname_of_class thy o fst);

   (*order fits nicely with composed projections*)

 fun namify_tyco thy "fun" = "Pure.fun"

   | namify_tyco thy tyco = namify thy NameSpace.base thyname_of_tyco tyco;

 fun namify_instance thy = namify thy (fn (class, tyco) => 

   NameSpace.base class ^ "_" ^ NameSpace.base tyco) thyname_of_instance;

 fun namify_const thy = namify thy NameSpace.base thyname_of_const;

 end; (* local *)

 (* data *)

 structure StringPairTab = Code_Name.StringPairTab;

 datatype naming = Naming of {

   class: class Symtab.table * Name.context,

   classrel: string StringPairTab.table * Name.context,

   tyco: string Symtab.table * Name.context,

   instance: string StringPairTab.table * Name.context,

   const: string Symtab.table * Name.context

 }

 fun dest_Naming (Naming naming) = naming;

 val empty_naming = Naming {

   class = (Symtab.empty, Name.context),

   classrel = (StringPairTab.empty, Name.context),

   tyco = (Symtab.empty, Name.context),

   instance = (StringPairTab.empty, Name.context),

   const = (Symtab.empty, Name.context)

 };

 local

   fun mk_naming (class, classrel, tyco, instance, const) =

     Naming { class = class, classrel = classrel,

       tyco = tyco, instance = instance, const = const };

   fun map_naming f (Naming { class, classrel, tyco, instance, const }) =

     mk_naming (f (class, classrel, tyco, instance, const));

 in

   fun map_class f = map_naming

     (fn (class, classrel, tyco, inst, const) =>

       (f class, classrel, tyco, inst, const));

   fun map_classrel f = map_naming

     (fn (class, classrel, tyco, inst, const) =>

       (class, f classrel, tyco, inst, const));

   fun map_tyco f = map_naming

     (fn (class, classrel, tyco, inst, const) =>

       (class, classrel, f tyco, inst, const));

   fun map_instance f = map_naming

     (fn (class, classrel, tyco, inst, const) =>

       (class, classrel, tyco, f inst, const));

   fun map_const f = map_naming

     (fn (class, classrel, tyco, inst, const) =>

       (class, classrel, tyco, inst, f const));

 end; (*local*)

 fun add_variant update (thing, name) (tab, used) =

   let

     val (name', used') = yield_singleton Name.variants name used;

     val tab' = update (thing, name') tab;

   in (tab', used') end;

 fun declare thy mapp lookup update namify thing =

   mapp (add_variant update (thing, namify thy thing))

   #> `(fn naming => the (lookup naming thing));

 (* lookup and declare *)

 local

 val suffix_class = "class";

 val suffix_classrel = "classrel"

 val suffix_tyco = "tyco";

 val suffix_instance = "inst";

 val suffix_const = "const";

 fun add_suffix nsp NONE = NONE

   | add_suffix nsp (SOME name) = SOME (NameSpace.append name nsp);

 in

 val lookup_class = add_suffix suffix_class

   oo Symtab.lookup o fst o #class o dest_Naming;

 val lookup_classrel = add_suffix suffix_classrel

   oo StringPairTab.lookup o fst o #classrel o dest_Naming;

 val lookup_tyco = add_suffix suffix_tyco

   oo Symtab.lookup o fst o #tyco o dest_Naming;

 val lookup_instance = add_suffix suffix_instance

   oo StringPairTab.lookup o fst o #instance o dest_Naming;

 val lookup_const = add_suffix suffix_const

   oo Symtab.lookup o fst o #const o dest_Naming;

 fun declare_class thy = declare thy map_class

   lookup_class Symtab.update_new namify_class;

 fun declare_classrel thy = declare thy map_classrel

   lookup_classrel StringPairTab.update_new namify_classrel;

 fun declare_tyco thy = declare thy map_tyco

   lookup_tyco Symtab.update_new namify_tyco;

 fun declare_instance thy = declare thy map_instance

   lookup_instance StringPairTab.update_new namify_instance;

 fun declare_const thy = declare thy map_const

   lookup_const Symtab.update_new namify_const;

 val unfold_fun = unfoldr

   (fn "Pure.fun.tyco" `%% [ty1, ty2] => SOME (ty1, ty2)

     | _ => NONE); (*depends on suffix_tyco and namify_tyco!*)

 end; (* local *)

 (** statements, abstract programs **)

 type typscheme = (vname * sort) list * itype;

 datatype stmt =

     NoStmt

   | Fun of string * (typscheme * ((iterm list * iterm) * (thm * bool)) list)

   | Datatype of string * ((vname * sort) list * (string * itype list) list)

   | Datatypecons of string * string

   | Class of class * (vname * ((class * string) list * (string * itype) list))

   | Classrel of class * class

   | Classparam of string * class

   | Classinst of (class * (string * (vname * sort) list))

         * ((class * (string * (string * dict list list))) list

       * ((string * const) * (thm * bool)) list);

 type program = stmt Graph.T;

 fun empty_funs program =

   Graph.fold (fn (name, (Fun (c, (_, [])), _)) => cons c

                | _ => I) program [];

 fun map_terms_bottom_up f (t as IConst _) = f t

   | map_terms_bottom_up f (t as IVar _) = f t

   | map_terms_bottom_up f (t1 `$ t2) = f

       (map_terms_bottom_up f t1 `$ map_terms_bottom_up f t2)

   | map_terms_bottom_up f ((v, ty) `|-> t) = f

       ((v, ty) `|-> map_terms_bottom_up f t)

   | map_terms_bottom_up f (ICase (((t, ty), ps), t0)) = f

       (ICase (((map_terms_bottom_up f t, ty), (map o pairself)

         (map_terms_bottom_up f) ps), map_terms_bottom_up f t0));

 fun map_terms_stmt f NoStmt = NoStmt

   | map_terms_stmt f (Fun (c, (tysm, eqs))) = Fun (c, (tysm, (map o apfst)

       (fn (ts, t) => (map f ts, f t)) eqs))

   | map_terms_stmt f (stmt as Datatype _) = stmt

   | map_terms_stmt f (stmt as Datatypecons _) = stmt

   | map_terms_stmt f (stmt as Class _) = stmt

   | map_terms_stmt f (stmt as Classrel _) = stmt

   | map_terms_stmt f (stmt as Classparam _) = stmt

   | map_terms_stmt f (Classinst (arity, (superarities, classparms))) =

       Classinst (arity, (superarities, (map o apfst o apsnd) (fn const =>

         case f (IConst const) of IConst const' => const') classparms));

 fun is_cons program name = case Graph.get_node program name

  of Datatypecons _ => true

   | _ => false;

 fun contr_classparam_typs program name = case Graph.get_node program name

  of Classparam (_, class) => let

         val Class (_, (_, (_, params))) = Graph.get_node program class;

         val SOME ty = AList.lookup (op =) params name;

         val (tys, res_ty) = unfold_fun ty;

         fun no_tyvar (_ `%% tys) = forall no_tyvar tys

           | no_tyvar (ITyVar _) = false;

       in if no_tyvar res_ty

         then map (fn ty => if no_tyvar ty then NONE else SOME ty) tys

         else []

       end

   | _ => [];

 (** translation kernel **)

 fun ensure_stmt lookup declare generate thing (dep, (naming, program)) =

   let

     fun add_dep name = case dep of NONE => I

       | SOME dep => Graph.add_edge (dep, name);

     val (name, naming') = case lookup naming thing

      of SOME name => (name, naming)

       | NONE => declare thing naming;

   in case try (Graph.get_node program) name

    of SOME stmt => program

         |> add_dep name

         |> pair naming'

         |> pair dep

         |> pair name

     | NONE => program

         |> Graph.default_node (name, NoStmt)

         |> add_dep name

         |> pair naming'

         |> curry generate (SOME name)

         ||> snd

         |-> (fn stmt => (apsnd o Graph.map_node name) (K stmt))

         |> pair dep

         |> pair name

   end;

 fun not_wellsorted thy thm ty sort e =

   let

     val err_class = Sorts.class_error (Syntax.pp_global thy) e;

     val err_thm = case thm

      of SOME thm => "\n(in defining equation " ^ Display.string_of_thm thm ^ ")" | NONE => "";

     val err_typ = "Type " ^ Syntax.string_of_typ_global thy ty ^ " not of sort "

       ^ Syntax.string_of_sort_global thy sort;

   in error ("Wellsortedness error" ^ err_thm ^ ":\n" ^ err_typ ^ "\n" ^ err_class) end;

 fun ensure_class thy (algbr as (_, algebra)) funcgr class =

   let

     val superclasses = (Sorts.certify_sort algebra o Sorts.super_classes algebra) class;

     val cs = #params (AxClass.get_info thy class);

     val stmt_class =

       fold_map (fn superclass => ensure_class thy algbr funcgr superclass

         ##>> ensure_classrel thy algbr funcgr (class, superclass)) superclasses

       ##>> fold_map (fn (c, ty) => ensure_const thy algbr funcgr c

         ##>> translate_typ thy algbr funcgr ty) cs

       #>> (fn info => Class (class, (unprefix "'" Name.aT, info)))

   in ensure_stmt lookup_class (declare_class thy) stmt_class class end

 and ensure_classrel thy algbr funcgr (subclass, superclass) =

   let

     val stmt_classrel =

       ensure_class thy algbr funcgr subclass

       ##>> ensure_class thy algbr funcgr superclass

       #>> Classrel;

   in ensure_stmt lookup_classrel (declare_classrel thy) stmt_classrel (subclass, superclass) end

 and ensure_tyco thy algbr funcgr tyco =

   let

     val stmt_datatype =

       let

         val (vs, cos) = Code.get_datatype thy tyco;

       in

         fold_map (translate_tyvar_sort thy algbr funcgr) vs

         ##>> fold_map (fn (c, tys) =>

           ensure_const thy algbr funcgr c

           ##>> fold_map (translate_typ thy algbr funcgr) tys) cos

         #>> (fn info => Datatype (tyco, info))

       end;

   in ensure_stmt lookup_tyco (declare_tyco thy) stmt_datatype tyco end

 and translate_tyvar_sort thy (algbr as (proj_sort, _)) funcgr (v, sort) =

   fold_map (ensure_class thy algbr funcgr) (proj_sort sort)

   #>> (fn sort => (unprefix "'" v, sort))

 and translate_typ thy algbr funcgr (TFree v_sort) =

       translate_tyvar_sort thy algbr funcgr v_sort

       #>> (fn (v, sort) => ITyVar v)

   | translate_typ thy algbr funcgr (Type (tyco, tys)) =

       ensure_tyco thy algbr funcgr tyco

       ##>> fold_map (translate_typ thy algbr funcgr) tys

       #>> (fn (tyco, tys) => tyco `%% tys)

 and translate_dicts thy (algbr as (proj_sort, algebra)) funcgr thm (ty, sort) =

   let

     val pp = Syntax.pp_global thy;

     datatype typarg =

         Global of (class * string) * typarg list list

       | Local of (class * class) list * (string * (int * sort));

     fun class_relation (Global ((_, tyco), yss), _) class =

           Global ((class, tyco), yss)

       | class_relation (Local (classrels, v), subclass) superclass =

           Local ((subclass, superclass) :: classrels, v);

     fun type_constructor tyco yss class =

       Global ((class, tyco), (map o map) fst yss);

     fun type_variable (TFree (v, sort)) =

       let

         val sort' = proj_sort sort;

       in map_index (fn (n, class) => (Local ([], (v, (n, sort'))), class)) sort' end;

     val typargs = Sorts.of_sort_derivation pp algebra

       {class_relation = class_relation, type_constructor = type_constructor,

        type_variable = type_variable} (ty, proj_sort sort)

       handle Sorts.CLASS_ERROR e => not_wellsorted thy thm ty sort e;

     fun mk_dict (Global (inst, yss)) =

           ensure_inst thy algbr funcgr inst

           ##>> (fold_map o fold_map) mk_dict yss

           #>> (fn (inst, dss) => DictConst (inst, dss))

       | mk_dict (Local (classrels, (v, (k, sort)))) =

           fold_map (ensure_classrel thy algbr funcgr) classrels

           #>> (fn classrels => DictVar (classrels, (unprefix "'" v, (k, length sort))))

   in fold_map mk_dict typargs end

 and translate_eq thy algbr funcgr (thm, linear) =

   let

     val (args, rhs) = (apfst (snd o strip_comb) o Logic.dest_equals

       o Logic.unvarify o prop_of) thm;

   in

     fold_map (translate_term thy algbr funcgr (SOME thm)) args

     ##>> translate_term thy algbr funcgr (SOME thm) rhs

     #>> rpair (thm, linear)

   end

 and ensure_inst thy (algbr as (_, algebra)) funcgr (class, tyco) =

   let

     val superclasses = (Sorts.certify_sort algebra o Sorts.super_classes algebra) class;

     val classparams = these (try (#params o AxClass.get_info thy) class);

     val vs = Name.names Name.context "'a" (Sorts.mg_domain algebra tyco [class]);

     val sorts' = Sorts.mg_domain (Sign.classes_of thy) tyco [class];

     val vs' = map2 (fn (v, sort1) => fn sort2 => (v,

       Sorts.inter_sort (Sign.classes_of thy) (sort1, sort2))) vs sorts';

     val arity_typ = Type (tyco, map TFree vs);

     val arity_typ' = Type (tyco, map (fn (v, sort) => TVar ((v, 0), sort)) vs');

     fun translate_superarity superclass =

       ensure_class thy algbr funcgr superclass

       ##>> ensure_classrel thy algbr funcgr (class, superclass)

       ##>> translate_dicts thy algbr funcgr NONE (arity_typ, [superclass])

       #>> (fn ((superclass, classrel), [DictConst (inst, dss)]) =>

             (superclass, (classrel, (inst, dss))));

     fun translate_classparam_inst (c, ty) =

       let

         val c_inst = Const (c, map_type_tfree (K arity_typ') ty);

         val thm = AxClass.unoverload_conv thy (Thm.cterm_of thy c_inst);

         val c_ty = (apsnd Logic.unvarifyT o dest_Const o snd

           o Logic.dest_equals o Thm.prop_of) thm;

       in

         ensure_const thy algbr funcgr c

         ##>> translate_const thy algbr funcgr (SOME thm) c_ty

         #>> (fn (c, IConst c_inst) => ((c, c_inst), (thm, true)))

       end;

     val stmt_inst =

       ensure_class thy algbr funcgr class

       ##>> ensure_tyco thy algbr funcgr tyco

       ##>> fold_map (translate_tyvar_sort thy algbr funcgr) vs

       ##>> fold_map translate_superarity superclasses

       ##>> fold_map translate_classparam_inst classparams

       #>> (fn ((((class, tyco), arity), superarities), classparams) =>

              Classinst ((class, (tyco, arity)), (superarities, classparams)));

   in ensure_stmt lookup_instance (declare_instance thy) stmt_inst (class, tyco) end

 and ensure_const thy algbr funcgr c =

   let

     fun stmt_datatypecons tyco =

       ensure_tyco thy algbr funcgr tyco

       #>> (fn tyco => Datatypecons (c, tyco));

     fun stmt_classparam class =

       ensure_class thy algbr funcgr class

       #>> (fn class => Classparam (c, class));

     fun stmt_fun ((vs, raw_ty), raw_thms) =

       let

         val ty = Logic.unvarifyT raw_ty;

         val thms = if (null o Term.typ_tfrees) ty orelse (null o fst o strip_type) ty

           then raw_thms

           else (map o apfst) (Code_Unit.expand_eta thy 1) raw_thms;

       in

         fold_map (translate_tyvar_sort thy algbr funcgr) vs

         ##>> translate_typ thy algbr funcgr ty

         ##>> fold_map (translate_eq thy algbr funcgr) thms

         #>> (fn info => Fun (c, info))

       end;

     val stmt_const = case Code.get_datatype_of_constr thy c

      of SOME tyco => stmt_datatypecons tyco

       | NONE => (case AxClass.class_of_param thy c

          of SOME class => stmt_classparam class

           | NONE => stmt_fun (Code_Funcgr.typ funcgr c, Code_Funcgr.eqns funcgr c))

   in ensure_stmt lookup_const (declare_const thy) stmt_const c end

 and translate_term thy algbr funcgr thm (Const (c, ty)) =

       translate_app thy algbr funcgr thm ((c, ty), [])

   | translate_term thy algbr funcgr thm (Free (v, _)) =

       pair (IVar v)

   | translate_term thy algbr funcgr thm (Abs (abs as (_, ty, _))) =

       let

         val (v, t) = Syntax.variant_abs abs;

       in

         translate_typ thy algbr funcgr ty

         ##>> translate_term thy algbr funcgr thm t

         #>> (fn (ty, t) => (v, ty) `|-> t)

       end

   | translate_term thy algbr funcgr thm (t as _ $ _) =

       case strip_comb t

        of (Const (c, ty), ts) =>

             translate_app thy algbr funcgr thm ((c, ty), ts)

         | (t', ts) =>

             translate_term thy algbr funcgr thm t'

             ##>> fold_map (translate_term thy algbr funcgr thm) ts

             #>> (fn (t, ts) => t `$$ ts)

 and translate_const thy algbr funcgr thm (c, ty) =

   let

     val tys = Sign.const_typargs thy (c, ty);

     val sorts = (map snd o fst o Code_Funcgr.typ funcgr) c;

     val tys_args = (fst o Term.strip_type) ty;

   in

     ensure_const thy algbr funcgr c

     ##>> fold_map (translate_dicts thy algbr funcgr thm) (tys ~~ sorts)

     ##>> fold_map (translate_typ thy algbr funcgr) tys_args

     #>> (fn ((c, iss), tys) => IConst (c, (iss, tys)))

   end

 and translate_app_default thy algbr funcgr thm (c_ty, ts) =

   translate_const thy algbr funcgr thm c_ty

   ##>> fold_map (translate_term thy algbr funcgr thm) ts

   #>> (fn (t, ts) => t `$$ ts)

 and translate_case thy algbr funcgr thm n cases (app as ((c, ty), ts)) =

   let

     val (tys, _) =

       (chop (1 + (if null cases then 1 else length cases)) o fst o strip_type) ty;

     val dt = nth ts n;

     val dty = nth tys n;

     fun is_undefined (Const (c, _)) = Code.is_undefined thy c

       | is_undefined _ = false;

     fun mk_case (co, n) t =

       let

         val (vs, body) = Term.strip_abs_eta n t;

         val selector = list_comb (Const (co, map snd vs ---> dty), map Free vs);

       in if is_undefined body then NONE else SOME (selector, body) end;

     fun mk_ds [] =

           let

             val ([v_ty], body) = Term.strip_abs_eta 1 (the_single (nth_drop n ts))

           in [(Free v_ty, body)] end

       | mk_ds cases = map_filter (uncurry mk_case)

           (AList.make (Code_Unit.no_args thy) cases ~~ nth_drop n ts);

   in

     translate_term thy algbr funcgr thm dt

     ##>> translate_typ thy algbr funcgr dty

     ##>> fold_map (fn (pat, body) => translate_term thy algbr funcgr thm pat

           ##>> translate_term thy algbr funcgr thm body) (mk_ds cases)

     ##>> translate_app_default thy algbr funcgr thm app

     #>> (fn (((dt, dty), ds), t0) => ICase (((dt, dty), ds), t0))

   end

 and translate_app thy algbr funcgr thm ((c, ty), ts) = case Code.get_case_data thy c

  of SOME (n, cases) => let val i = 1 + (if null cases then 1 else length cases) in

       if length ts < i then

         let

           val k = length ts;

           val tys = (curry Library.take (i - k) o curry Library.drop k o fst o strip_type) ty;

           val ctxt = (fold o fold_aterms)

             (fn Free (v, _) => Name.declare v | _ => I) ts Name.context;

           val vs = Name.names ctxt "a" tys;

         in

           fold_map (translate_typ thy algbr funcgr) tys

           ##>> translate_case thy algbr funcgr thm n cases ((c, ty), ts @ map Free vs)

           #>> (fn (tys, t) => map2 (fn (v, _) => pair v) vs tys `|--> t)

         end

       else if length ts > i then

         translate_case thy algbr funcgr thm n cases ((c, ty), Library.take (i, ts))

         ##>> fold_map (translate_term thy algbr funcgr thm) (Library.drop (i, ts))

         #>> (fn (t, ts) => t `$$ ts)

       else

         translate_case thy algbr funcgr thm n cases ((c, ty), ts)

       end

   | NONE => translate_app_default thy algbr funcgr thm ((c, ty), ts);

 (** generated programs **)

 (* store *)

 structure Program = CodeDataFun

 (

   type T = naming * program;

   val empty = (empty_naming, Graph.empty);

   fun purge thy cs (naming, program) =

     let

       val names_delete = cs

         |> map_filter (lookup_const naming)

         |> filter (can (Graph.get_node program))

         |> Graph.all_preds program;

       val program' = Graph.del_nodes names_delete program;

     in (naming, program') end;

 );

 val cached_program = Program.get;

 fun generate thy funcgr f name =

   Program.change_yield thy (fn naming_program => (NONE, naming_program)

     |> f thy (Code.operational_algebra thy) funcgr name

     |-> (fn name => fn (_, naming_program) => (name, naming_program)));

 (* program generation *)

 fun consts_program thy cs =

   let

     fun project_consts cs (naming, program) =

       let

         val cs_all = Graph.all_succs program cs;

       in (cs, (naming, Graph.subgraph (member (op =) cs_all) program)) end;

     fun generate_consts thy algebra funcgr =

       fold_map (ensure_const thy algebra funcgr);

   in

     generate thy (Code_Funcgr.make thy cs) generate_consts cs

     |-> project_consts

   end;

 (* value evaluation *)

 fun ensure_value thy algbr funcgr t = 

   let

     val ty = fastype_of t;

     val vs = fold_term_types (K (fold_atyps (insert (eq_fst op =)

       o dest_TFree))) t [];

     val stmt_value =

       fold_map (translate_tyvar_sort thy algbr funcgr) vs

       ##>> translate_typ thy algbr funcgr ty

       ##>> translate_term thy algbr funcgr NONE t

       #>> (fn ((vs, ty), t) => Fun

         (Term.dummy_patternN, ((vs, ty), [(([], t), (Drule.dummy_thm, true))])));

     fun term_value (dep, (naming, program1)) =

       let

         val Fun (_, ((vs, ty), [(([], t), _)])) =

           Graph.get_node program1 Term.dummy_patternN;

         val deps = Graph.imm_succs program1 Term.dummy_patternN;

         val program2 = Graph.del_nodes [Term.dummy_patternN] program1;

         val deps_all = Graph.all_succs program2 deps;

         val program3 = Graph.subgraph (member (op =) deps_all) program2;

       in (((naming, program3), (((vs, ty), t), deps)), (dep, (naming, program2))) end;

   in

     ensure_stmt ((K o K) NONE) pair stmt_value Term.dummy_patternN

     #> snd

     #> term_value

   end;

 fun eval eval_kind thy evaluator =

   let

     fun evaluator'' evaluator''' funcgr t =

       let

         val (((naming, program), (vs_ty_t, deps)), _) = generate thy funcgr ensure_value t;

       in evaluator''' naming program vs_ty_t deps end;

     fun evaluator' t =

       let

         val (t', evaluator''') = evaluator t;

       in (t', evaluator'' evaluator''') end;

   in eval_kind thy evaluator' end

 fun eval_conv thy = eval Code_Funcgr.eval_conv thy;

 fun eval_term thy = eval Code_Funcgr.eval_term thy;

 end; (*struct*)

 structure Basic_Code_Thingol: BASIC_CODE_THINGOL = Code_Thingol;