diff --git a/src/Tools/Code/code_thingol.ML b/src/Tools/Code/code_thingol.ML
--- a/src/Tools/Code/code_thingol.ML
+++ b/src/Tools/Code/code_thingol.ML
@@ -1,1042 +1,1042 @@
 (*  Title:      Tools/Code/code_thingol.ML
     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 `|=>;
 infixr 3 `|==>;
 
 signature BASIC_CODE_THINGOL =
 sig
   type vname = string;
   datatype dict =
       Dict of (class * class) list * plain_dict
   and plain_dict = 
       Dict_Const of (string * class) * dict list list
     | Dict_Var of { var: vname, index: int, length: int, class: class, unique: bool };
   datatype itype =
       `%% of string * itype list
     | ITyVar of vname;
   type const = { sym: Code_Symbol.T, typargs: itype list, dicts: dict list list,
     dom: itype list, annotation: itype option };
   datatype iterm =
       IConst of const
     | IVar of vname option
     | `$ of iterm * iterm
     | `|=> of (vname option * itype) * iterm
     | ICase of { term: iterm, typ: itype, clauses: (iterm * iterm) list, primitive: iterm };
   val `-> : itype * itype -> itype;
   val `$$ : iterm * iterm list -> iterm;
   val `|==> : (vname option * 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_fun_n: int -> itype -> itype list * itype
   val unfold_app: iterm -> iterm * iterm list
   val unfold_abs: iterm -> (vname option * itype) list * iterm
   val split_let: iterm -> (((iterm * itype) * iterm) * iterm) option
   val split_let_no_pat: iterm -> (((string option * itype) * iterm) * iterm) option
   val unfold_let: iterm -> ((iterm * itype) * iterm) list * iterm
   val unfold_let_no_pat: iterm -> ((string option * itype) * iterm) list * iterm
   val split_pat_abs: iterm -> ((iterm * itype) * iterm) option
   val unfold_pat_abs: iterm -> (iterm * itype) list * iterm
   val unfold_const_app: iterm -> (const * iterm list) option
   val is_IVar: iterm -> bool
   val is_IAbs: iterm -> bool
   val eta_expand: int -> const * iterm list -> iterm
   val contains_dict_var: iterm -> bool
   val unambiguous_dictss: dict list list -> bool
   val add_constsyms: iterm -> Code_Symbol.T list -> Code_Symbol.T list
   val add_tyconames: iterm -> string list -> string list
   val fold_varnames: (string -> 'a -> 'a) -> iterm -> 'a -> 'a
 
   datatype stmt =
       NoStmt
     | Fun of (typscheme * ((iterm list * iterm) * (thm option * bool)) list) * thm option
     | Datatype of vname list *
         ((string * vname list (*type argument wrt. canonical order*)) * itype list) list
     | Datatypecons of string
     | Class of vname * ((class * class) list * (string * itype) list)
     | Classrel of class * class
     | Classparam of class
     | Classinst of { class: string, tyco: string, vs: (vname * sort) list,
         superinsts: (class * dict list list) list,
         inst_params: ((string * (const * int)) * (thm * bool)) list,
         superinst_params: ((string * (const * int)) * (thm * bool)) list };
   type program = stmt Code_Symbol.Graph.T
   val unimplemented: program -> string list
   val implemented_deps: program -> string list
   val map_terms_bottom_up: (iterm -> iterm) -> iterm -> iterm
   val map_terms_stmt: (iterm -> iterm) -> stmt -> stmt
   val is_constr: program -> Code_Symbol.T -> bool
   val is_case: stmt -> bool
   val group_stmts: Proof.context -> program
     -> ((Code_Symbol.T * stmt) list * (Code_Symbol.T * stmt) list
       * ((Code_Symbol.T * stmt) list * (Code_Symbol.T * stmt) list)) list
 
   val read_const_exprs: Proof.context -> string list -> string list
   val consts_program: Proof.context -> string list -> program
   val dynamic_conv: Proof.context -> (program
     -> typscheme * iterm -> Code_Symbol.T list -> conv)
     -> conv
   val dynamic_value: Proof.context -> ((term -> term) -> 'a -> 'a) -> (program
     -> term -> typscheme * iterm -> Code_Symbol.T list -> 'a)
     -> term -> 'a
   val static_conv_thingol: { ctxt: Proof.context, consts: string list }
     -> ({ program: program, deps: string list }
       -> Proof.context -> typscheme * iterm -> Code_Symbol.T list -> conv)
     -> Proof.context -> conv
   val static_conv_isa: { ctxt: Proof.context, consts: string list }
     -> (program -> Proof.context -> term -> conv)
     -> Proof.context -> conv
   val static_value: { ctxt: Proof.context, lift_postproc: ((term -> term) -> 'a -> 'a), consts: string list }
     -> ({ program: program, deps: string list }
       -> Proof.context -> term -> typscheme * iterm -> Code_Symbol.T list -> 'a)
     -> Proof.context -> term -> 'a
 end;
 
 structure Code_Thingol : CODE_THINGOL =
 struct
 
 open Basic_Code_Symbol;
 
 (** 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, terms **)
 
 type vname = string;
 
 datatype dict =
     Dict of (class * class) list * plain_dict
 and plain_dict = 
     Dict_Const of (string * class) * dict list list
   | Dict_Var of { var: vname, index: int, length: int, class: class, unique: bool };
 
 datatype itype =
     `%% of string * itype list
   | ITyVar of vname;
 
 fun ty1 `-> ty2 = "fun" `%% [ty1, ty2];
 
 val unfold_fun = unfoldr
   (fn "fun" `%% [ty1, ty2] => SOME (ty1, ty2)
     | _ => NONE);
 
 fun unfold_fun_n n ty =
   let
     val (tys1, ty1) = unfold_fun ty;
     val (tys3, tys2) = chop n tys1;
     val ty3 = Library.foldr (op `->) (tys2, ty1);
   in (tys3, ty3) end;
 
 type const = { sym: Code_Symbol.T, typargs: itype list, dicts: dict list list,
   dom: itype list, annotation: itype option };
 
 datatype iterm =
     IConst of const
   | IVar of vname option
   | `$ of iterm * iterm
   | `|=> of (vname option * itype) * iterm
   | ICase of { term: iterm, typ: itype, clauses: (iterm * iterm) list, primitive: iterm };
     (*see also signature*)
 
 fun is_IVar (IVar _) = true
   | is_IVar _ = false;
 
 fun is_IAbs (_ `|=> _) = true
   | is_IAbs _ = false;
 
 val op `$$ = Library.foldl (op `$);
 val op `|==> = Library.foldr (op `|=>);
 
 val unfold_app = unfoldl
   (fn op `$ t => SOME t
     | _ => NONE);
 
 val unfold_abs = unfoldr
   (fn op `|=> t => SOME t
     | _ => NONE);
 
 val split_let = 
   (fn ICase { term = t, typ = ty, clauses = [(p, body)], ... } => SOME (((p, ty), t), body)
     | _ => NONE);
 
 val split_let_no_pat = 
   (fn ICase { term = t, typ = ty, clauses = [(IVar v, body)], ... } => SOME (((v, ty), t), body)
     | _ => NONE);
 
 val unfold_let = unfoldr split_let;
 
 val unfold_let_no_pat = unfoldr split_let_no_pat;
 
 fun unfold_const_app t =
  case unfold_app t
   of (IConst c, ts) => SOME (c, ts)
    | _ => NONE;
 
 fun fold_constexprs f =
   let
     fun fold' (IConst c) = f c
       | fold' (IVar _) = I
       | fold' (t1 `$ t2) = fold' t1 #> fold' t2
       | fold' (_ `|=> t) = fold' t
       | fold' (ICase { term = t, clauses = clauses, ... }) = fold' t
           #> fold (fn (p, body) => fold' p #> fold' body) clauses
   in fold' end;
 
 val add_constsyms = fold_constexprs (fn { sym, ... } => insert (op =) sym);
 
 fun add_tycos (tyco `%% tys) = insert (op =) tyco #> fold add_tycos tys
   | add_tycos (ITyVar _) = I;
 
 val add_tyconames = fold_constexprs (fn { typargs = tys, ... } => fold add_tycos tys);
 
 fun fold_varnames f =
   let
     fun fold_aux add_vars f =
       let
         fun fold_term _ (IConst _) = I
           | fold_term vs (IVar (SOME v)) = if member (op =) vs v then I else f v
           | fold_term _ (IVar NONE) = I
           | fold_term vs (t1 `$ t2) = fold_term vs t1 #> fold_term vs t2
           | fold_term vs ((SOME v, _) `|=> t) = fold_term (insert (op =) v vs) t
           | fold_term vs ((NONE, _) `|=> t) = fold_term vs t
           | fold_term vs (ICase { term = t, clauses = clauses, ... }) =
               fold_term vs t #> fold (fold_clause vs) clauses
         and fold_clause vs (p, t) = fold_term (add_vars p vs) t;
       in fold_term [] end
     fun add_vars t = fold_aux add_vars (insert (op =)) t;
   in fold_aux add_vars f end;
 
 fun exists_var t v = fold_varnames (fn w => fn b => v = w orelse b) t false;
 
 fun split_pat_abs ((NONE, ty) `|=> t) = SOME ((IVar NONE, ty), t)
   | split_pat_abs ((SOME v, ty) `|=> t) = SOME (case t
      of ICase { term = IVar (SOME w), clauses = [(p, body)], ... } =>
           if v = w andalso (exists_var p v orelse not (exists_var body v))
           then ((p, ty), body)
           else ((IVar (SOME v), ty), t)
       | _ => ((IVar (SOME v), ty), t))
   | split_pat_abs _ = NONE;
 
 val unfold_pat_abs = unfoldr split_pat_abs;
 
 fun unfold_abs_eta [] t = ([], t)
   | unfold_abs_eta (_ :: tys) (v_ty `|=> t) =
       let
         val (vs_tys, t') = unfold_abs_eta tys t;
       in (v_ty :: vs_tys, t') end
   | unfold_abs_eta tys t =
       let
         val ctxt = fold_varnames Name.declare t Name.context;
         val vs_tys = (map o apfst) SOME (Name.invent_names ctxt "a" tys);
       in (vs_tys, t `$$ map (IVar o fst) vs_tys) end;
 
 fun eta_expand k (const as { dom = tys, ... }, ts) =
   let
     val j = length ts;
     val l = k - j;
     val _ = if l > length tys
       then error "Impossible eta-expansion" else ();
     val vars = (fold o fold_varnames) Name.declare ts Name.context;
     val vs_tys = (map o apfst) SOME
       (Name.invent_names vars "a" ((take l o drop j) tys));
   in vs_tys `|==> IConst const `$$ ts @ map (IVar o fst) vs_tys end;
 
 fun exists_dict_var f (Dict (_, d)) = exists_plain_dict_var_pred f d
 and exists_plain_dict_var_pred f (Dict_Const (_, dss)) = exists_dictss_var f dss
   | exists_plain_dict_var_pred f (Dict_Var x) = f x
 and exists_dictss_var f dss = (exists o exists) (exists_dict_var f) dss;
 
 fun contains_dict_var (IConst { dicts = dss, ... }) = exists_dictss_var (K true) dss
   | contains_dict_var (IVar _) = false
   | contains_dict_var (t1 `$ t2) = contains_dict_var t1 orelse contains_dict_var t2
   | contains_dict_var (_ `|=> t) = contains_dict_var t
   | contains_dict_var (ICase { primitive = t, ... }) = contains_dict_var t;
 
 val unambiguous_dictss = not o exists_dictss_var (fn { unique, ... } => not unique);
 
 
 (** statements, abstract programs **)
 
 type typscheme = (vname * sort) list * itype;
 datatype stmt =
     NoStmt
   | Fun of (typscheme * ((iterm list * iterm) * (thm option * bool)) list) * thm option
   | Datatype of vname list * ((string * vname list) * itype list) list
   | Datatypecons of string
   | Class of vname * ((class * class) list * (string * itype) list)
   | Classrel of class * class
   | Classparam of class
   | Classinst of { class: string, tyco: string, vs: (vname * sort) list,
       superinsts: (class * dict list list) list,
       inst_params: ((string * (const * int)) * (thm * bool)) list,
       superinst_params: ((string * (const * int)) * (thm * bool)) list };
 
 type program = stmt Code_Symbol.Graph.T;
 
 fun unimplemented program =
   Code_Symbol.Graph.fold (fn (Constant c, (NoStmt, _)) => cons c | _ => I) program [];
 
 fun implemented_deps program =
   Code_Symbol.Graph.keys program
   |> subtract (op =) (Code_Symbol.Graph.all_preds program (map Constant (unimplemented program)))
   |> map_filter (fn Constant c => SOME c | _ => NONE);
 
 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 { term = t, typ = ty, clauses = clauses, primitive = t0 }) = f
       (ICase { term = map_terms_bottom_up f t, typ = ty,
         clauses = (map o apply2) (map_terms_bottom_up f) clauses,
         primitive = map_terms_bottom_up f t0 });
 
 fun map_classparam_instances_as_term f =
   (map o apfst o apsnd o apfst) (fn const => case f (IConst const) of IConst const' => const')
 
 fun map_terms_stmt f NoStmt = NoStmt
   | map_terms_stmt f (Fun ((tysm, eqs), case_cong)) = Fun ((tysm, (map o apfst)
       (fn (ts, t) => (map f ts, f t)) eqs), case_cong)
   | 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 { class, tyco, vs, superinsts,
       inst_params, superinst_params }) =
         Classinst { class = class, tyco = tyco, vs = vs, superinsts = superinsts,
           inst_params = map_classparam_instances_as_term f inst_params,
           superinst_params = map_classparam_instances_as_term f superinst_params };
 
 fun is_constr program sym = case Code_Symbol.Graph.get_node program sym
  of Datatypecons _ => true
   | _ => false;
 
 fun is_case (Fun (_, SOME _)) = true
   | is_case _ = false;
 
 fun linear_stmts program =
   rev (Code_Symbol.Graph.strong_conn program)
   |> map (AList.make (Code_Symbol.Graph.get_node program));
 
 fun group_stmts ctxt program =
   let
     fun is_fun (_, Fun _) = true | is_fun _ = false;
     fun is_datatypecons (_, Datatypecons _) = true | is_datatypecons _ = false;
     fun is_datatype (_, Datatype _) = true | is_datatype _ = false;
     fun is_class (_, Class _) = true | is_class _ = false;
     fun is_classrel (_, Classrel _) = true | is_classrel _ = false;
     fun is_classparam (_, Classparam _) = true | is_classparam _ = false;
     fun is_classinst (_, Classinst _) = true | is_classinst _ = false;
     fun group stmts =
       if forall (is_datatypecons orf is_datatype) stmts
       then (filter is_datatype stmts, [], ([], []))
       else if forall (is_class orf is_classrel orf is_classparam) stmts
       then ([], filter is_class stmts, ([], []))
       else if forall (is_fun orf is_classinst) stmts
       then ([], [], List.partition is_fun stmts)
       else error ("Illegal mutual dependencies: " ^ (commas
         o map (Code_Symbol.quote ctxt o fst)) stmts);
   in
     linear_stmts program
     |> map group
   end;
 
 
 (** translation kernel **)
 
 (* generic mechanisms *)
 
 fun ensure_stmt symbolize generate x (deps, program) =
   let
     val sym = symbolize x;
     val add_dep = case deps of [] => I
       | dep :: _ => Code_Symbol.Graph.add_edge (dep, sym);
   in
     if can (Code_Symbol.Graph.get_node program) sym
     then
       program
       |> add_dep
       |> pair deps
       |> pair x
     else
       program
       |> Code_Symbol.Graph.default_node (sym, NoStmt)
       |> add_dep
       |> curry generate (sym :: deps)
       ||> snd
       |-> (fn stmt => (Code_Symbol.Graph.map_node sym) (K stmt))
       |> pair deps
       |> pair x
   end;
 
 exception PERMISSIVE of unit;
 
 fun translation_error ctxt permissive some_thm deps msg sub_msg =
   if permissive
   then raise PERMISSIVE ()
   else
     let
       val thm_msg =
         Option.map (fn thm => "in code equation " ^ Thm.string_of_thm ctxt thm) some_thm;
       val dep_msg = if null (tl deps) then NONE
         else SOME ("with dependency "
           ^ space_implode " -> " (map (Code_Symbol.quote ctxt) (rev deps)));
       val thm_dep_msg = case (thm_msg, dep_msg)
        of (SOME thm_msg, SOME dep_msg) => "\n(" ^ thm_msg ^ ",\n" ^ dep_msg ^ ")"
         | (SOME thm_msg, NONE) => "\n(" ^ thm_msg ^ ")"
         | (NONE, SOME dep_msg) => "\n(" ^ dep_msg ^ ")"
         | (NONE, NONE) => ""
     in error (msg ^ thm_dep_msg ^ ":\n" ^ sub_msg) end;
 
 fun maybe_permissive f prgrm =
   f prgrm |>> SOME handle PERMISSIVE () => (NONE, prgrm);
 
 fun not_wellsorted ctxt permissive some_thm deps ty sort e =
   let
     val err_class = Sorts.class_error (Context.Proof ctxt) e;
     val err_typ =
       "Type " ^ Syntax.string_of_typ ctxt ty ^ " not of sort " ^
         Syntax.string_of_sort ctxt sort;
   in
     translation_error ctxt permissive some_thm deps
       "Wellsortedness error" (err_typ ^ "\n" ^ err_class)
   end;
 
 
 (* inference of type annotations for disambiguation with type classes *)
 
 fun mk_tagged_type (true, T) = Type ("", [T])
   | mk_tagged_type (false, T) = T;
 
 fun dest_tagged_type (Type ("", [T])) = (true, T)
   | dest_tagged_type T = (false, T);
 
 val untag_term = map_types (snd o dest_tagged_type);
 
 fun tag_term (proj_sort, _) eqngr =
   let
     val has_sort_constraints = exists (not o null) o map proj_sort o Code_Preproc.sortargs eqngr;
     fun tag (Const (_, T')) (Const (c, T)) =
         Const (c,
           mk_tagged_type (not (null (Term.add_tvarsT T' [])) andalso has_sort_constraints c, T))
       | tag (t1 $ u1) (t $ u) = tag t1 t $ tag u1 u
       | tag (Abs (_, _, t1)) (Abs (x, T, t)) = Abs (x, T, tag t1 t)
       | tag (Free _) (t as Free _) = t
       | tag (Var _) (t as Var _) = t
       | tag (Bound _) (t as Bound _) = t;
   in tag end
 
 fun annotate ctxt algbr eqngr (c, ty) args rhs =
   let
     val erase = map_types (fn _ => Type_Infer.anyT []);
     val reinfer = singleton (Type_Infer_Context.infer_types ctxt);
     val lhs = list_comb (Const (c, ty), map (map_types Type.strip_sorts o fst) args);
     val reinferred_rhs = snd (Logic.dest_equals (reinfer (Logic.mk_equals (lhs, erase rhs))));
   in tag_term algbr eqngr reinferred_rhs rhs end
 
 fun annotate_eqns ctxt algbr eqngr (c, ty) eqns =
   let
     val ctxt' = ctxt |> Proof_Context.theory_of |> Proof_Context.init_global
       |> Config.put Type_Infer_Context.const_sorts false;
       (*avoid spurious fixed variables: there is no eigen context for equations*)
   in
     map (apfst (fn (args, (rhs, some_abs)) => (args,
       (annotate ctxt' algbr eqngr (c, ty) args rhs, some_abs)))) eqns
   end;
 
 (* abstract dictionary construction *)
 
 datatype typarg_witness =
     Weakening of (class * class) list * plain_typarg_witness
 and plain_typarg_witness =
     Global of (string * class) * typarg_witness list list
   | Local of { var: string, index: int, sort: sort, unique: bool };
 
 fun brand_unique unique (w as Global _) = w
   | brand_unique unique (Local { var, index, sort, unique = _ }) =
       Local { var = var, index = index, sort = sort, unique = unique };
 
 fun construct_dictionaries ctxt (proj_sort, algebra) permissive some_thm (ty, sort) (deps, program) =
   let
     fun class_relation unique (Weakening (classrels, x), sub_class) super_class =
       Weakening ((sub_class, super_class) :: classrels, brand_unique unique x);
     fun type_constructor (tyco, _) dss class =
       Weakening ([], Global ((tyco, class), (map o map) fst dss));
     fun type_variable (TFree (v, sort)) =
       let
         val sort' = proj_sort sort;
       in map_index (fn (n, class) => (Weakening ([], Local
         { var = v, index = n, sort = sort', unique = true }), class)) sort'
       end;
     val typarg_witnesses = Sorts.of_sort_derivation algebra
       {class_relation = fn _ => fn unique =>
          Sorts.classrel_derivation algebra (class_relation unique),
        type_constructor = type_constructor,
        type_variable = type_variable} (ty, proj_sort sort)
       handle Sorts.CLASS_ERROR e => not_wellsorted ctxt permissive some_thm deps ty sort e;
   in (typarg_witnesses, (deps, program)) end;
 
 
 (* translation *)
 
 fun ensure_tyco ctxt algbr eqngr permissive tyco =
   let
     val thy = Proof_Context.theory_of ctxt;
     val ((vs, cos), _) = Code.get_type thy tyco;
     val stmt_datatype =
       fold_map (translate_tyvar_sort ctxt algbr eqngr permissive) vs
       #>> map fst
       ##>> fold_map (fn (c, (vs, tys)) =>
         ensure_const ctxt algbr eqngr permissive c
         ##>> pair (map (unprefix "'" o fst) vs)
         ##>> fold_map (translate_typ ctxt algbr eqngr permissive) tys) cos
       #>> Datatype;
   in ensure_stmt Type_Constructor stmt_datatype tyco end
 and ensure_const ctxt algbr eqngr permissive c =
   let
     val thy = Proof_Context.theory_of ctxt;
     fun stmt_datatypecons tyco =
       ensure_tyco ctxt algbr eqngr permissive tyco
       #>> Datatypecons;
     fun stmt_classparam class =
       ensure_class ctxt algbr eqngr permissive class
       #>> Classparam;
     fun stmt_fun cert = case Code.equations_of_cert thy cert
      of (_, NONE) => pair NoStmt
       | ((vs, ty), SOME eqns) =>
           let
             val eqns' = annotate_eqns ctxt algbr eqngr (c, ty) eqns
             val some_case_cong = Code.get_case_cong thy c;
           in
             fold_map (translate_tyvar_sort ctxt algbr eqngr permissive) vs
             ##>> translate_typ ctxt algbr eqngr permissive ty
             ##>> translate_eqns ctxt algbr eqngr permissive eqns'
             #>>
              (fn (_, NONE) => NoStmt
                | (tyscm, SOME eqns) => Fun ((tyscm, eqns), some_case_cong))
           end;
     val stmt_const = case Code.get_type_of_constr_or_abstr 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_Preproc.cert eqngr c))
   in ensure_stmt Constant stmt_const c end
 and ensure_class ctxt (algbr as (_, algebra)) eqngr permissive class =
   let
     val thy = Proof_Context.theory_of ctxt;
     val super_classes = (Sorts.minimize_sort algebra o Sorts.super_classes algebra) class;
     val cs = #params (Axclass.get_info thy class);
     val stmt_class =
       fold_map (fn super_class =>
         ensure_classrel ctxt algbr eqngr permissive (class, super_class)) super_classes
       ##>> fold_map (fn (c, ty) => ensure_const ctxt algbr eqngr permissive c
         ##>> translate_typ ctxt algbr eqngr permissive ty) cs
       #>> (fn info => Class (unprefix "'" Name.aT, info))
   in ensure_stmt Type_Class stmt_class class end
 and ensure_classrel ctxt algbr eqngr permissive (sub_class, super_class) =
   let
     val stmt_classrel =
       ensure_class ctxt algbr eqngr permissive sub_class
       ##>> ensure_class ctxt algbr eqngr permissive super_class
       #>> Classrel;
   in ensure_stmt Class_Relation stmt_classrel (sub_class, super_class) end
 and ensure_inst ctxt (algbr as (_, algebra)) eqngr permissive (tyco, class) =
   let
     val thy = Proof_Context.theory_of ctxt;
     val super_classes = (Sorts.minimize_sort algebra o Sorts.super_classes algebra) class;
     val these_class_params = these o try (#params o Axclass.get_info thy);
     val class_params = these_class_params class;
     val superclass_params = maps these_class_params
       ((Sorts.complete_sort algebra o Sorts.super_classes algebra) class);
     val vs = Name.invent_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_super_instance super_class =
       ensure_class ctxt algbr eqngr permissive super_class
       ##>> translate_dicts ctxt algbr eqngr permissive NONE (arity_typ, [super_class])
       #>> (fn (super_class, [Dict ([], Dict_Const (_, dss))]) => (super_class, dss));
     fun translate_classparam_instance (c, ty) =
       let
         val raw_const = Const (c, map_type_tfree (K arity_typ') ty);
         val dom_length = length (fst (strip_type ty))
         val thm = Axclass.unoverload_conv ctxt (Thm.cterm_of ctxt raw_const);
         val const = (apsnd Logic.unvarifyT_global o dest_Const o snd
           o Logic.dest_equals o Thm.prop_of) thm;
       in
         ensure_const ctxt algbr eqngr permissive c
         ##>> translate_const ctxt algbr eqngr permissive (SOME thm) (const, NONE)
         #>> (fn (c, IConst const') => ((c, (const', dom_length)), (thm, true)))
       end;
     val stmt_inst =
       ensure_class ctxt algbr eqngr permissive class
       ##>> ensure_tyco ctxt algbr eqngr permissive tyco
       ##>> fold_map (translate_tyvar_sort ctxt algbr eqngr permissive) vs
       ##>> fold_map translate_super_instance super_classes
       ##>> fold_map translate_classparam_instance class_params
       ##>> fold_map translate_classparam_instance superclass_params
       #>> (fn (((((class, tyco), vs), superinsts), inst_params), superinst_params) =>
           Classinst { class = class, tyco = tyco, vs = vs,
             superinsts = superinsts, inst_params = inst_params, superinst_params = superinst_params });
   in ensure_stmt Class_Instance stmt_inst (tyco, class) end
 and translate_typ ctxt algbr eqngr permissive (TFree (v, _)) =
       pair (ITyVar (unprefix "'" v))
   | translate_typ ctxt algbr eqngr permissive (Type (tyco, tys)) =
       ensure_tyco ctxt algbr eqngr permissive tyco
       ##>> fold_map (translate_typ ctxt algbr eqngr permissive) tys
       #>> (fn (tyco, tys) => tyco `%% tys)
 and translate_term ctxt algbr eqngr permissive some_thm (Const (c, ty), some_abs) =
       translate_app ctxt algbr eqngr permissive some_thm (((c, ty), []), some_abs)
   | translate_term ctxt algbr eqngr permissive some_thm (Free (v, _), some_abs) =
       pair (IVar (SOME v))
   | translate_term ctxt algbr eqngr permissive some_thm (Abs (v, ty, t), some_abs) =
       let
-        val (v', t') = Syntax_Trans.variant_abs (Name.desymbolize (SOME false) v, ty, t);
+        val (v', t') = Term.dest_abs (Name.desymbolize (SOME false) v, ty, t);
         val v'' = if Term.used_free v' t' then SOME v' else NONE
       in
         translate_typ ctxt algbr eqngr permissive ty
         ##>> translate_term ctxt algbr eqngr permissive some_thm (t', some_abs)
         #>> (fn (ty, t) => (v'', ty) `|=> t)
       end
   | translate_term ctxt algbr eqngr permissive some_thm (t as _ $ _, some_abs) =
       case strip_comb t
        of (Const (c, ty), ts) =>
             translate_app ctxt algbr eqngr permissive some_thm (((c, ty), ts), some_abs)
         | (t', ts) =>
             translate_term ctxt algbr eqngr permissive some_thm (t', some_abs)
             ##>> fold_map (translate_term ctxt algbr eqngr permissive some_thm o rpair NONE) ts
             #>> (fn (t, ts) => t `$$ ts)
 and translate_eqn ctxt algbr eqngr permissive ((args, (rhs, some_abs)), (some_thm, proper)) =
   fold_map (translate_term ctxt algbr eqngr permissive some_thm) args
   ##>> translate_term ctxt algbr eqngr permissive some_thm (rhs, some_abs)
   #>> rpair (some_thm, proper)
 and translate_eqns ctxt algbr eqngr permissive eqns =
   maybe_permissive (fold_map (translate_eqn ctxt algbr eqngr permissive) eqns)
 and translate_const ctxt algbr eqngr permissive some_thm ((c, ty), some_abs) (deps, program) =
   let
     val thy = Proof_Context.theory_of ctxt;
     val _ = if (case some_abs of NONE => true | SOME abs => not (c = abs))
         andalso Code.is_abstr thy c
         then translation_error ctxt permissive some_thm deps
           "Abstraction violation" ("constant " ^ Code.string_of_const thy c)
       else ()
   in translate_const_proper ctxt algbr eqngr permissive some_thm (c, ty) (deps, program) end
 and translate_const_proper ctxt algbr eqngr permissive some_thm (c, ty) =
   let
     val thy = Proof_Context.theory_of ctxt;
     val (annotate, ty') = dest_tagged_type ty;
     val typargs = Sign.const_typargs thy (c, ty');
     val sorts = Code_Preproc.sortargs eqngr c;
     val (dom, range) = Term.strip_type ty';
   in
     ensure_const ctxt algbr eqngr permissive c
     ##>> fold_map (translate_typ ctxt algbr eqngr permissive) typargs
     ##>> fold_map (translate_dicts ctxt algbr eqngr permissive some_thm) (typargs ~~ sorts)
     ##>> fold_map (translate_typ ctxt algbr eqngr permissive) (ty' :: dom)
     #>> (fn (((c, typargs), dss), annotation :: dom) =>
       IConst { sym = Constant c, typargs = typargs, dicts = dss,
         dom = dom, annotation =
           if annotate then SOME annotation else NONE })
   end
 and translate_app_const ctxt algbr eqngr permissive some_thm ((c_ty, ts), some_abs) =
   translate_const ctxt algbr eqngr permissive some_thm (c_ty, some_abs)
   ##>> fold_map (translate_term ctxt algbr eqngr permissive some_thm o rpair NONE) ts
   #>> (fn (t, ts) => t `$$ ts)
 and translate_case ctxt algbr eqngr permissive some_thm (num_args, (t_pos, case_pats)) (c_ty, ts) =
   let
     val thy = Proof_Context.theory_of ctxt;
     fun arg_types num_args ty = fst (chop num_args (binder_types ty));
     val tys = arg_types num_args (snd c_ty);
     val ty = nth tys t_pos;
     fun mk_constr NONE t = NONE
       | mk_constr (SOME c) t =
           let
             val n = Code.args_number thy c;
           in SOME ((c, arg_types n (fastype_of (untag_term t)) ---> ty), n) end;
     val constrs =
       if null case_pats then []
       else map_filter I (map2 mk_constr case_pats (nth_drop t_pos ts));
     fun disjunctive_varnames ts =
       let
         val vs = (fold o fold_varnames) (insert (op =)) ts [];
       in fn pat => null (inter (op =) vs (fold_varnames (insert (op =)) pat [])) end;
     fun purge_unused_vars_in t =
       let
         val vs = fold_varnames (insert (op =)) t [];
       in
         map_terms_bottom_up (fn IVar (SOME v) =>
           IVar (if member (op =) vs v then SOME v else NONE) | t => t)
       end;
     fun collapse_clause vs_map ts body =
       case body
        of IConst { sym = Constant c, ... } => if Code.is_undefined thy c
             then []
             else [(ts, body)]
         | ICase { term = IVar (SOME v), clauses = clauses, ... } =>
             if forall (fn (pat', body') => exists_var pat' v
               orelse not (exists_var body' v)) clauses
               andalso forall (disjunctive_varnames ts o fst) clauses
             then case AList.lookup (op =) vs_map v
              of SOME i => maps (fn (pat', body') =>
                   collapse_clause (AList.delete (op =) v vs_map)
                     (nth_map i (K pat') ts |> map (purge_unused_vars_in body')) body') clauses
               | NONE => [(ts, body)]
             else [(ts, body)]
         | _ => [(ts, body)];
     fun mk_clause mk tys t =
       let
         val (vs, body) = unfold_abs_eta tys t;
         val vs_map = fold_index (fn (i, (SOME v, _)) => cons (v, i) | _ => I) vs [];
         val ts = map (IVar o fst) vs;
       in map mk (collapse_clause vs_map ts body) end;
     fun casify constrs ty t_app ts =
       let
         val t = nth ts t_pos;
         val ts_clause = nth_drop t_pos ts;
         val clauses = if null case_pats
           then mk_clause (fn ([t], body) => (t, body)) [ty] (the_single ts_clause)
           else maps (fn ((constr as IConst { dom = tys, ... }, n), t) =>
             mk_clause (fn (ts, body) => (constr `$$ ts, body)) (take n tys) t)
               (constrs ~~ (map_filter (fn (NONE, _) => NONE | (SOME _, t) => SOME t)
                 (case_pats ~~ ts_clause)));
       in ICase { term = t, typ = ty, clauses = clauses, primitive = t_app `$$ ts } end;
   in
     translate_const ctxt algbr eqngr permissive some_thm (c_ty, NONE)
     ##>> fold_map (fn (constr, n) => translate_const ctxt algbr eqngr permissive some_thm (constr, NONE)
       #>> rpair n) constrs
     ##>> translate_typ ctxt algbr eqngr permissive ty
     ##>> fold_map (translate_term ctxt algbr eqngr permissive some_thm o rpair NONE) ts
     #>> (fn (((t, constrs), ty), ts) =>
       casify constrs ty t ts)
   end
 and translate_app_case ctxt algbr eqngr permissive some_thm (case_schema as (num_args, _)) ((c, ty), ts) =
   if length ts < num_args then
     let
       val k = length ts;
       val tys = (take (num_args - k) o drop k o fst o strip_type) ty;
       val names = Name.build_context (ts |> (fold o fold_aterms) Term.declare_term_frees);
       val vs = Name.invent_names names "a" tys;
     in
       fold_map (translate_typ ctxt algbr eqngr permissive) tys
       ##>> translate_case ctxt algbr eqngr permissive some_thm case_schema ((c, ty), ts @ map Free vs)
       #>> (fn (tys, t) => map2 (fn (v, _) => pair (SOME v)) vs tys `|==> t)
     end
   else if length ts > num_args then
     translate_case ctxt algbr eqngr permissive some_thm case_schema ((c, ty), take num_args ts)
     ##>> fold_map (translate_term ctxt algbr eqngr permissive some_thm o rpair NONE) (drop num_args ts)
     #>> (fn (t, ts) => t `$$ ts)
   else
     translate_case ctxt algbr eqngr permissive some_thm case_schema ((c, ty), ts)
 and translate_app ctxt algbr eqngr permissive some_thm (c_ty_ts as ((c, _), _), some_abs) =
   case Code.get_case_schema (Proof_Context.theory_of ctxt) c
    of SOME case_schema => translate_app_case ctxt algbr eqngr permissive some_thm case_schema c_ty_ts
     | NONE => translate_app_const ctxt algbr eqngr permissive some_thm (c_ty_ts, some_abs)
 and translate_tyvar_sort ctxt (algbr as (proj_sort, _)) eqngr permissive (v, sort) =
   fold_map (ensure_class ctxt algbr eqngr permissive) (proj_sort sort)
   #>> (fn sort => (unprefix "'" v, sort))
 and translate_dicts ctxt algbr eqngr permissive some_thm (ty, sort) =
   let
     fun mk_dict (Weakening (classrels, d)) =
           fold_map (ensure_classrel ctxt algbr eqngr permissive) classrels
           ##>> mk_plain_dict d
           #>> Dict 
     and mk_plain_dict (Global (inst, dss)) =
           ensure_inst ctxt algbr eqngr permissive inst
           ##>> (fold_map o fold_map) mk_dict dss
           #>> Dict_Const
       | mk_plain_dict (Local { var, index, sort, unique }) =
           ensure_class ctxt algbr eqngr permissive (nth sort index)
           #>> (fn class => Dict_Var { var = unprefix "'" var, index = index,
             length = length sort, class = class, unique = unique })
   in
     construct_dictionaries ctxt algbr permissive some_thm (ty, sort)
     #-> (fn typarg_witnesses => fold_map mk_dict typarg_witnesses)
   end;
 
 
 (* store *)
 
 structure Program = Code_Data
 (
   type T = program;
   val empty = Code_Symbol.Graph.empty;
 );
 
 fun invoke_generation ignore_cache ctxt generate thing =
   Program.change_yield
     (if ignore_cache then NONE else SOME (Proof_Context.theory_of ctxt))
     (fn program => ([], program)
       |> generate thing
       |-> (fn thing => fn (_, program) => (thing, program)));
 
 
 (* program generation *)
 
 fun check_abstract_constructors thy consts =
   case filter (Code.is_abstr thy) consts of
     [] => ()
   | abstrs => error ("Cannot export abstract constructor(s): "
       ^ commas (map (Code.string_of_const thy) abstrs));
 
 fun invoke_generation_for_consts ctxt { ignore_cache, permissive } { algebra, eqngr } consts =
   let
     val thy = Proof_Context.theory_of ctxt;
     val _ = if permissive then ()
       else check_abstract_constructors thy consts;
   in
     Code_Preproc.timed "translating program" #ctxt
     (fn { ctxt, algebra, eqngr, consts } => invoke_generation ignore_cache ctxt
       (fold_map (ensure_const ctxt algebra eqngr permissive)) consts)
       { ctxt = ctxt, algebra = algebra, eqngr = eqngr, consts = consts }
   end;
 
 fun invoke_generation_for_consts' ctxt ignore_cache_and_permissive consts =
   invoke_generation_for_consts ctxt
     { ignore_cache = ignore_cache_and_permissive, permissive = ignore_cache_and_permissive }
     (Code_Preproc.obtain ignore_cache_and_permissive
       { ctxt = ctxt, consts = consts, terms = []}) consts
   |> snd;
 
 fun invoke_generation_for_consts'' ctxt algebra_eqngr =
   invoke_generation_for_consts ctxt
     { ignore_cache = true, permissive = false }
     algebra_eqngr
   #> (fn (deps, program) => { deps = deps, program = program });
 
 fun consts_program_permissive ctxt =
   invoke_generation_for_consts' ctxt true;
 
 fun consts_program ctxt consts =
   let
     fun project program = Code_Symbol.Graph.restrict
       (member (op =) (Code_Symbol.Graph.all_succs program
         (map Constant consts))) program;
   in
     invoke_generation_for_consts' ctxt false consts
     |> project
   end;
 
 
 (* value evaluation *)
 
 fun ensure_value ctxt algbr eqngr t =
   let
     val ty = fastype_of t;
     val vs = fold_term_types (K (fold_atyps (insert (eq_fst op =)
       o dest_TFree))) t [];
     val t' = annotate ctxt algbr eqngr (\<^const_name>\<open>Pure.dummy_pattern\<close>, ty) [] t;
     val dummy_constant = Constant \<^const_name>\<open>Pure.dummy_pattern\<close>;
     val stmt_value =
       fold_map (translate_tyvar_sort ctxt algbr eqngr false) vs
       ##>> translate_typ ctxt algbr eqngr false ty
       ##>> translate_term ctxt algbr eqngr false NONE (t', NONE)
       #>> (fn ((vs, ty), t) => Fun
         (((vs, ty), [(([], t), (NONE, true))]), NONE));
     fun term_value (_, program1) =
       let
         val Fun ((vs_ty, [(([], t), _)]), _) =
           Code_Symbol.Graph.get_node program1 dummy_constant;
         val deps' = Code_Symbol.Graph.immediate_succs program1 dummy_constant;
         val program2 = Code_Symbol.Graph.del_node dummy_constant program1;
         val deps_all = Code_Symbol.Graph.all_succs program2 deps';
         val program3 = Code_Symbol.Graph.restrict (member (op =) deps_all) program2;
        in ((program3, ((vs_ty, t), deps')), (deps', program2)) end;
   in
     ensure_stmt Constant stmt_value \<^const_name>\<open>Pure.dummy_pattern\<close>
     #> snd
     #> term_value
   end;
 
 fun dynamic_evaluation comp ctxt algebra eqngr t =
   let
     val ((program, (vs_ty_t', deps)), _) =
       Code_Preproc.timed "translating term" #ctxt
       (fn { ctxt, algebra, eqngr, t } =>
         invoke_generation false ctxt (ensure_value ctxt algebra eqngr) t)
         { ctxt = ctxt, algebra = algebra, eqngr = eqngr, t = t };
   in comp program t vs_ty_t' deps end;
 
 fun dynamic_conv ctxt conv =
   Code_Preproc.dynamic_conv ctxt
     (dynamic_evaluation (fn program => fn _ => conv program) ctxt);
 
 fun dynamic_value ctxt postproc comp =
   Code_Preproc.dynamic_value ctxt postproc
     (dynamic_evaluation comp ctxt);
 
 fun static_evaluation ctxt consts algebra_eqngr static_eval =
   static_eval (invoke_generation_for_consts'' ctxt algebra_eqngr consts);
 
 fun static_evaluation_thingol ctxt consts (algebra_eqngr as { algebra, eqngr }) static_eval =
   let
     fun evaluation program dynamic_eval ctxt t =
       let
         val ((_, ((vs_ty', t'), deps)), _) =
           Code_Preproc.timed "translating term" #ctxt
           (fn { ctxt, t } =>
             ensure_value ctxt algebra eqngr t ([], program))
             { ctxt = ctxt, t = t };
       in dynamic_eval ctxt t (vs_ty', t') deps end;
   in
     static_evaluation ctxt consts algebra_eqngr (fn program_deps =>
       evaluation (#program program_deps) (static_eval program_deps))
   end;
 
 fun static_evaluation_isa ctxt consts algebra_eqngr static_eval =
   static_evaluation ctxt consts algebra_eqngr (fn program_deps =>
     (static_eval (#program program_deps)));
 
 fun static_conv_thingol (ctxt_consts as { ctxt, consts }) conv =
   Code_Preproc.static_conv ctxt_consts (fn algebra_eqngr =>
     static_evaluation_thingol ctxt consts algebra_eqngr
       (fn program_deps =>
         let
           val static_conv = conv program_deps;
         in 
           fn ctxt => fn _ => fn vs_ty => fn deps => static_conv ctxt vs_ty deps
         end));
 
 fun static_conv_isa (ctxt_consts as { ctxt, consts }) conv =
   Code_Preproc.static_conv ctxt_consts (fn algebra_eqngr =>
     static_evaluation_isa ctxt consts algebra_eqngr conv);
 
 fun static_value (ctxt_postproc_consts as { ctxt, consts, ... }) comp =
   Code_Preproc.static_value ctxt_postproc_consts (fn algebra_eqngr =>
     static_evaluation_thingol ctxt consts algebra_eqngr comp);
 
 
 (** constant expressions **)
 
 fun read_const_exprs_internal ctxt =
   let
     val thy = Proof_Context.theory_of ctxt;
     fun this_theory name =
       if Context.theory_name thy = name then thy
       else Context.get_theory {long = false} thy name;
 
     fun consts_of thy' =
       fold (fn (c, (_, NONE)) => cons c | _ => I)
         (#constants (Consts.dest (Sign.consts_of thy'))) []
       |> filter_out (Code.is_abstr thy);
     fun belongs_here thy' c = forall
       (fn thy'' => not (Sign.declared_const thy'' c)) (Theory.parents_of thy');
     fun consts_of_select thy' = filter (belongs_here thy') (consts_of thy');
     fun read_const_expr str =
       (case Syntax.parse_input ctxt (K NONE) (K Markup.empty) (SOME o Symbol_Pos.implode o #1) str of
         SOME "_" => ([], consts_of thy)
       | SOME s =>
           (case try (unsuffix "._") s of
             SOME name => ([], consts_of_select (this_theory name))
           | NONE => ([Code.read_const thy str], []))
       | NONE => ([Code.read_const thy str], []));
   in apply2 flat o split_list o map read_const_expr end;
 
 fun read_const_exprs_all ctxt = op @ o read_const_exprs_internal ctxt;
 
 fun read_const_exprs ctxt const_exprs =
   let
     val (consts, consts_permissive) =
       read_const_exprs_internal ctxt const_exprs;
     val consts' = 
       consts_program_permissive ctxt consts_permissive
       |> implemented_deps
       |> filter_out (Code.is_abstr (Proof_Context.theory_of ctxt));
   in union (op =) consts' consts end;
 
 
 (** diagnostic commands **)
 
 fun code_depgr ctxt consts =
   let
     val { eqngr, ... } = Code_Preproc.obtain true
       { ctxt = ctxt, consts = consts, terms = [] };
     val all_consts = Graph.all_succs eqngr consts;
   in Graph.restrict (member (op =) all_consts) eqngr end;
 
 fun code_thms ctxt = Pretty.writeln o Code_Preproc.pretty ctxt o code_depgr ctxt;
 
 fun coalesce_strong_conn gr =
   let
     val xss = Graph.strong_conn gr;
     val xss_ys = map (fn xs => (xs, commas xs)) xss;
     val y_for = the o AList.lookup (op =) (maps (fn (xs, y) => map (fn x => (x, y)) xs) xss_ys);
     fun coalesced_succs_for xs = maps (Graph.immediate_succs gr) xs
       |> subtract (op =) xs
       |> map y_for
       |> distinct (op =);
     val succs = map (fn (xs, _) => (xs, coalesced_succs_for xs)) xss_ys;
   in
     map (fn (xs, y) => ((y, xs), (maps (Graph.get_node gr) xs, (the o AList.lookup (op =) succs) xs))) xss_ys
   end;
 
 fun code_deps ctxt consts =
   let
     val thy = Proof_Context.theory_of ctxt;
     fun mk_entry ((name, consts), (ps, deps)) =
       let
         val label = commas (map (Code.string_of_const thy) consts);
       in ((name, Graph_Display.content_node label (Pretty.str label :: ps)), deps) end;
   in
     code_depgr ctxt consts
     |> Graph.map (K (Code.pretty_cert thy o snd))
     |> coalesce_strong_conn
     |> map mk_entry
     |> Graph_Display.display_graph
   end;
 
 local
 
 fun code_thms_cmd ctxt = code_thms ctxt o read_const_exprs_all ctxt;
 fun code_deps_cmd ctxt = code_deps ctxt o read_const_exprs_all ctxt;
 
 in
 
 val _ =
   Outer_Syntax.command \<^command_keyword>\<open>code_thms\<close>
     "print system of code equations for code"
     (Scan.repeat1 Parse.term >> (fn cs =>
       Toplevel.keep (fn st => code_thms_cmd (Toplevel.context_of st) cs)));
 
 val _ =
   Outer_Syntax.command \<^command_keyword>\<open>code_deps\<close>
     "visualize dependencies of code equations for code"
     (Scan.repeat1 Parse.term >> (fn cs =>
       Toplevel.keep (fn st => code_deps_cmd (Toplevel.context_of st) cs)));
 
 end;
 
 end; (*struct*)
 
 
 structure Basic_Code_Thingol: BASIC_CODE_THINGOL = Code_Thingol;