(*  Title:      Tools/Code/code_scala.ML

     Author:     Florian Haftmann, TU Muenchen

 Serializer for Scala.

 *)

 signature CODE_SCALA =

 sig

   val target: string

   val setup: theory -> theory

 end;

 structure Code_Scala : CODE_SCALA =

 struct

 val target = "Scala";

 open Basic_Code_Thingol;

 open Code_Printer;

 infixr 5 @@;

 infixr 5 @|;

 (** Scala serializer **)

 fun print_scala_stmt labelled_name syntax_tyco syntax_const reserved

     args_num is_singleton_constr (deresolve, deresolve_full) =

   let

     fun lookup_tyvar tyvars = lookup_var tyvars o first_upper;

     fun intro_tyvars vs = intro_vars (map (first_upper o fst) vs);

     fun print_tyco_expr tyvars fxy (tyco, tys) = applify "[" "]"

           (print_typ tyvars NOBR) fxy ((str o deresolve) tyco) tys

     and print_typ tyvars fxy (tyco `%% tys) = (case syntax_tyco tyco

          of NONE => print_tyco_expr tyvars fxy (tyco, tys)

           | SOME (i, print) => print (print_typ tyvars) fxy tys)

       | print_typ tyvars fxy (ITyVar v) = (str o lookup_tyvar tyvars) v;

     fun print_dicttyp tyvars (class, ty) = print_tyco_expr tyvars NOBR (class, [ty]);

     fun print_tupled_typ tyvars ([], ty) =

           print_typ tyvars NOBR ty

       | print_tupled_typ tyvars ([ty1], ty2) =

           concat [print_typ tyvars BR ty1, str "=>", print_typ tyvars NOBR ty2]

       | print_tupled_typ tyvars (tys, ty) =

           concat [enum "," "(" ")" (map (print_typ tyvars NOBR) tys),

             str "=>", print_typ tyvars NOBR ty];

     fun constraint p1 p2 = Pretty.block [p1, str ":", Pretty.brk 1, p2];

     fun print_var vars NONE = str "_"

       | print_var vars (SOME v) = (str o lookup_var vars) v

     fun print_term tyvars is_pat some_thm vars fxy (IConst c) =

           print_app tyvars is_pat some_thm vars fxy (c, [])

       | print_term tyvars is_pat some_thm vars fxy (t as (t1 `$ t2)) =

           (case Code_Thingol.unfold_const_app t

            of SOME app => print_app tyvars is_pat some_thm vars fxy app

             | _ => applify "(" ")" (print_term tyvars is_pat some_thm vars NOBR) fxy

                 (print_term tyvars is_pat some_thm vars BR t1) [t2])

       | print_term tyvars is_pat some_thm vars fxy (IVar v) =

           print_var vars v

       | print_term tyvars is_pat some_thm vars fxy ((v, ty) `|=> t) =

           let

             val vars' = intro_vars (the_list v) vars;

           in

             concat [

               enclose "(" ")" [constraint (print_var vars' v) (print_typ tyvars NOBR ty)],

               str "=>",

               print_term tyvars false some_thm vars' NOBR t

             ]

           end 

       | print_term tyvars is_pat some_thm vars fxy (ICase (cases as (_, t0))) =

           (case Code_Thingol.unfold_const_app t0

            of SOME (c_ts as ((c, _), _)) => if is_none (syntax_const c)

                 then print_case tyvars some_thm vars fxy cases

                 else print_app tyvars is_pat some_thm vars fxy c_ts

             | NONE => print_case tyvars some_thm vars fxy cases)

     and print_app tyvars is_pat some_thm vars fxy

         (app as ((c, ((arg_typs, _), function_typs)), ts)) =

       let

         val k = length ts;

         val arg_typs' = if is_pat orelse

           (is_none (syntax_const c) andalso is_singleton_constr c) then [] else arg_typs;

         val (l, print') = case syntax_const c

          of NONE => (args_num c, fn fxy => fn ts => applify "(" ")"

               (print_term tyvars is_pat some_thm vars NOBR) fxy

                 (applify "[" "]" (print_typ tyvars NOBR)

                   NOBR ((str o deresolve) c) arg_typs') ts)

           | SOME (Plain_const_syntax (k, s)) => (k, fn fxy => fn ts => applify "(" ")"

               (print_term tyvars is_pat some_thm vars NOBR) fxy

                 (applify "[" "]" (print_typ tyvars NOBR)

                   NOBR (str s) arg_typs') ts)

           | SOME (Complex_const_syntax (k, print)) =>

               (k, fn fxy => fn ts => print (print_term tyvars is_pat some_thm) some_thm vars fxy

                 (ts ~~ take k function_typs))

       in if k = l then print' fxy ts

       else if k < l then

         print_term tyvars is_pat some_thm vars fxy (Code_Thingol.eta_expand l app)

       else let

         val (ts1, ts23) = chop l ts;

       in

         Pretty.block (print' BR ts1 :: map (fn t => Pretty.block

           [str ".apply(", print_term tyvars is_pat some_thm vars NOBR t, str ")"]) ts23)

       end end

     and print_bind tyvars some_thm fxy p =

       gen_print_bind (print_term tyvars true) some_thm fxy p

     and print_case tyvars some_thm vars fxy (cases as ((_, [_]), _)) =

           let

             val (binds, body) = Code_Thingol.unfold_let (ICase cases);

             fun print_match ((IVar NONE, _), t) vars =

                   ((true, print_term tyvars false some_thm vars NOBR t), vars)

               | print_match ((pat, ty), t) vars =

                   vars

                   |> print_bind tyvars some_thm BR pat

                   |>> (fn p => (false, concat [str "val", constraint p (print_typ tyvars NOBR ty),

                       str "=", print_term tyvars false some_thm vars NOBR t]))

             val (seps_ps, vars') = fold_map print_match binds vars;

             val all_seps_ps = seps_ps @ [(true, print_term tyvars false some_thm vars' NOBR body)];

             fun insert_seps [(_, p)] = [p]

               | insert_seps ((_, p) :: (seps_ps as (sep, _) :: _)) =

                   (if sep then Pretty.block [p, str ";"] else p) :: insert_seps seps_ps

           in brackify_block fxy (str "{") (insert_seps all_seps_ps) (str "}")

           end

       | print_case tyvars some_thm vars fxy (((t, ty), clauses as _ :: _), _) =

           let

             fun print_select (pat, body) =

               let

                 val (p_pat, vars') = print_bind tyvars some_thm NOBR pat vars;

                 val p_body = print_term tyvars false some_thm vars' NOBR body

               in concat [str "case", p_pat, str "=>", p_body] end;

           in brackify_block fxy

             (concat [print_term tyvars false some_thm vars NOBR t, str "match", str "{"])

             (map print_select clauses)

             (str "}") 

           end

       | print_case tyvars some_thm vars fxy ((_, []), _) =

           (brackify fxy o Pretty.breaks o map str) ["error(\"empty case\")"];

     fun print_context tyvars vs name = applify "[" "]"

       (fn (v, sort) => (Pretty.block o map str)

         (lookup_tyvar tyvars v :: maps (fn sort => [": ", deresolve sort]) sort))

           NOBR ((str o deresolve) name) vs;

     fun print_defhead tyvars vars name vs params tys ty =

       Pretty.block [str "def ", constraint (applify "(" ")" (fn (param, ty) =>

         constraint ((str o lookup_var vars) param) (print_typ tyvars NOBR ty))

           NOBR (print_context tyvars vs name) (params ~~ tys)) (print_typ tyvars NOBR ty),

             str " ="];

     fun print_def name (vs, ty) [] =

           let

             val (tys, ty') = Code_Thingol.unfold_fun ty;

             val params = Name.invents (snd reserved) "a" (length tys);

             val tyvars = intro_tyvars vs reserved;

             val vars = intro_vars params reserved;

           in

             concat [print_defhead tyvars vars name vs params tys ty',

               str ("error(\"" ^ name ^ "\")")]

           end

       | print_def name (vs, ty) eqs =

           let

             val tycos = fold (fn ((ts, t), _) =>

               fold Code_Thingol.add_tyconames (t :: ts)) eqs [];

             val tyvars = reserved

               |> intro_base_names

                    (is_none o syntax_tyco) deresolve tycos

               |> intro_tyvars vs;

             val simple = case eqs

              of [((ts, _), _)] => forall Code_Thingol.is_IVar ts

               | _ => false;

             val consts = fold Code_Thingol.add_constnames

               (map (snd o fst) eqs) [];

             val vars1 = reserved

               |> intro_base_names

                    (is_none o syntax_const) deresolve consts

             val params = if simple

               then (map (fn IVar (SOME x) => x) o fst o fst o hd) eqs

               else aux_params vars1 (map (fst o fst) eqs);

             val vars2 = intro_vars params vars1;

             val (tys', ty') = Code_Thingol.unfold_fun_n (length params) ty;

             fun print_tuple [p] = p

               | print_tuple ps = enum "," "(" ")" ps;

             fun print_rhs vars' ((_, t), (some_thm, _)) =

               print_term tyvars false some_thm vars' NOBR t;

             fun print_clause (eq as ((ts, _), (some_thm, _))) =

               let

                 val vars' = intro_vars ((fold o Code_Thingol.fold_varnames)

                   (insert (op =)) ts []) vars1;

               in

                 concat [str "case",

                   print_tuple (map (print_term tyvars true some_thm vars' NOBR) ts),

                   str "=>", print_rhs vars' eq]

               end;

             val head = print_defhead tyvars vars2 name vs params tys' ty';

           in if simple then

             concat [head, print_rhs vars2 (hd eqs)]

           else

             Pretty.block_enclose

               (concat [head, print_tuple (map (str o lookup_var vars2) params),

                 str "match", str "{"], str "}")

               (map print_clause eqs)

           end;

     val print_method = str o Library.enclose "`" "`" o space_implode "+"

       o Long_Name.explode o deresolve_full;

     fun print_stmt (name, Code_Thingol.Fun (_, (((vs, ty), raw_eqs), _))) =

           print_def name (vs, ty) (filter (snd o snd) raw_eqs)

       | print_stmt (name, Code_Thingol.Datatype (_, (vs, cos))) =

           let

             val tyvars = intro_tyvars vs reserved;

             fun print_co ((co, _), []) =

                   concat [str "final", str "case", str "object", (str o deresolve) co,

                     str "extends", applify "[" "]" I NOBR ((str o deresolve) name)

                       (replicate (length vs) (str "Nothing"))]

               | print_co ((co, vs_args), tys) =

                   concat [applify "(" ")"

                     (fn (v, arg) => constraint (str v) (print_typ tyvars NOBR arg)) NOBR

                     (applify "[" "]" (str o lookup_tyvar tyvars) NOBR ((concat o map str)

                       ["final", "case", "class", deresolve co]) vs_args)

                     (Name.names (snd reserved) "a" tys),

                     str "extends",

                     applify "[" "]" (str o lookup_tyvar tyvars o fst) NOBR

                       ((str o deresolve) name) vs

                   ];

           in

             Pretty.chunks (applify "[" "]" (str o prefix "+" o lookup_tyvar tyvars o fst)

               NOBR ((concat o map str) ["abstract", "sealed", "class", deresolve name]) vs

                 :: map print_co cos)

           end

       | print_stmt (name, Code_Thingol.Class (_, (v, (super_classes, classparams)))) =

           let

             val tyvars = intro_tyvars [(v, [name])] reserved;

             fun add_typarg s = Pretty.block

               [str s, str "[", (str o lookup_tyvar tyvars) v, str "]"];

             fun print_super_classes [] = NONE

               | print_super_classes classes = SOME (concat (str "extends"

                   :: separate (str "with") (map (add_typarg o deresolve o fst) classes)));

             fun print_classparam_val (classparam, ty) =

               concat [str "val", constraint (print_method classparam)

                 ((print_tupled_typ tyvars o Code_Thingol.unfold_fun) ty)];

             fun print_classparam_def (classparam, ty) =

               let

                 val (tys, ty) = Code_Thingol.unfold_fun ty;

                 val [implicit_name] = Name.invents (snd reserved) (lookup_tyvar tyvars v) 1;

                 val proto_vars = intro_vars [implicit_name] reserved;

                 val auxs = Name.invents (snd proto_vars) "a" (length tys);

                 val vars = intro_vars auxs proto_vars;

               in

                 concat [str "def", constraint (Pretty.block [applify "(" ")"

                   (fn (aux, ty) => constraint ((str o lookup_var vars) aux)

                   (print_typ tyvars NOBR ty)) NOBR (add_typarg (deresolve classparam))

                   (auxs ~~ tys), str "(implicit ", str implicit_name, str ": ",

                   add_typarg (deresolve name), str ")"]) (print_typ tyvars NOBR ty), str "=",

                   applify "(" ")" (str o lookup_var vars) NOBR

                   (Pretty.block [str implicit_name, str ".", print_method classparam]) auxs]

               end;

           in

             Pretty.chunks (

               (Pretty.block_enclose

                 (concat ([str "trait", (add_typarg o deresolve) name]

                   @ the_list (print_super_classes super_classes) @ [str "{"]), str "}")

                 (map print_classparam_val classparams))

               :: map print_classparam_def classparams

             )

           end

       | print_stmt (name, Code_Thingol.Classinst ((class, (tyco, vs)),

             (super_instances, (classparam_instances, further_classparam_instances)))) =

           let

             val tyvars = intro_tyvars vs reserved;

             val classtyp = (class, tyco `%% map (ITyVar o fst) vs);

             fun print_classparam_instance ((classparam, const as (_, (_, tys))), (thm, _)) =

               let

                 val aux_tys = Name.names (snd reserved) "a" tys;

                 val auxs = map fst aux_tys;

                 val vars = intro_vars auxs reserved;

                 val aux_abstr = if null auxs then [] else [enum "," "(" ")"

                   (map (fn (aux, ty) => constraint ((str o lookup_var vars) aux)

                   (print_typ tyvars NOBR ty)) aux_tys), str "=>"];

               in 

                 concat ([str "val", print_method classparam, str "="]

                   @ aux_abstr @| print_app tyvars false (SOME thm) vars NOBR

                     (const, map (IVar o SOME) auxs))

               end;

           in

             Pretty.block_enclose (concat [str "implicit def",

               constraint (print_context tyvars vs name) (print_dicttyp tyvars classtyp),

               str "=", str "new", print_dicttyp tyvars classtyp, str "{"], str "}")

                 (map print_classparam_instance (classparam_instances @ further_classparam_instances))

           end;

   in print_stmt end;

 local

 (* hierarchical module name space *)

 datatype node =

     Dummy

   | Stmt of Code_Thingol.stmt

   | Module of (string list * (string * node) Graph.T);

 in

 fun scala_program_of_program labelled_name reserved module_alias program =

   let

     (* building module name hierarchy *)

     fun alias_fragments name = case module_alias name

      of SOME name' => Long_Name.explode name'

       | NONE => map (fn name => fst (yield_singleton Name.variants name reserved))

           (Long_Name.explode name);

     val module_names = Graph.fold (insert (op =) o fst o dest_name o fst) program [];

     val fragments_tab = fold (fn name => Symtab.update

       (name, alias_fragments name)) module_names Symtab.empty;

     val dest_name = Code_Printer.dest_name #>> (the o Symtab.lookup fragments_tab);

     (* building empty module hierarchy *)

     val empty_module = ([], Graph.empty);

     fun map_module f (Module content) = Module (f content);

     fun change_module [] = I

       | change_module (name_fragment :: name_fragments) =

           apsnd o Graph.map_node name_fragment o apsnd o map_module

             o change_module name_fragments;

     fun ensure_module name_fragment (implicits, nodes) =

       if can (Graph.get_node nodes) name_fragment then (implicits, nodes)

       else (implicits,

         nodes |> Graph.new_node (name_fragment, (name_fragment, Module empty_module)));

     fun allocate_module [] = I

       | allocate_module (name_fragment :: name_fragments) =

           ensure_module name_fragment

           #> (apsnd o Graph.map_node name_fragment o apsnd o map_module o allocate_module) name_fragments;

     val empty_program = Symtab.fold (fn (_, fragments) => allocate_module fragments)

       fragments_tab empty_module;

     (* distribute statements over hierarchy *)

     fun add_stmt name stmt =

       let

         val (name_fragments, base) = dest_name name;

         fun is_classinst stmt = case stmt

          of Code_Thingol.Classinst _ => true

           | _ => false;

         val implicit_deps = filter (is_classinst o Graph.get_node program)

           (Graph.imm_succs program name);

       in

         change_module name_fragments (fn (implicits, nodes) =>

           (union (op =) implicit_deps implicits, Graph.new_node (name, (base, Stmt stmt)) nodes))

       end;

     fun add_dependency name name' =

       let

         val (name_fragments, base) = dest_name name;

         val (name_fragments', base') = dest_name name';

         val (name_fragments_common, (diff, diff')) =

           chop_prefix (op =) (name_fragments, name_fragments');

         val dep = if null diff then (name, name') else (hd diff, hd diff')

       in (change_module name_fragments_common o apsnd) (Graph.add_edge dep) end;

     val proto_program = empty_program

       |> Graph.fold (fn (name, (stmt, _)) => add_stmt name stmt) program

       |> Graph.fold (fn (name, (_, (_, names))) => fold (add_dependency name) names) program;

     (* name declarations *)

     fun namify_module name_fragment ((nsp_class, nsp_object), nsp_common) =

       let

         val declare = Name.declare name_fragment;

       in (name_fragment, ((declare nsp_class, declare nsp_object), declare nsp_common)) end;

     fun namify_class base ((nsp_class, nsp_object), nsp_common) =

       let

         val (base', nsp_class') = yield_singleton Name.variants base nsp_class

       in (base', ((nsp_class', nsp_object), Name.declare base' nsp_common)) end;

     fun namify_object base ((nsp_class, nsp_object), nsp_common) =

       let

         val (base', nsp_object') = yield_singleton Name.variants base nsp_object

       in (base', ((nsp_class, nsp_object'), Name.declare base' nsp_common)) end;

     fun namify_common upper base ((nsp_class, nsp_object), nsp_common) =

       let

         val (base', nsp_common') =

           yield_singleton Name.variants (if upper then first_upper base else base) nsp_common

       in

         (base',

           ((Name.declare base' nsp_class, Name.declare base' nsp_object), nsp_common'))

       end;

     fun namify_stmt (Code_Thingol.Fun _) = namify_object

       | namify_stmt (Code_Thingol.Datatype _) = namify_class

       | namify_stmt (Code_Thingol.Datatypecons _) = namify_common true

       | namify_stmt (Code_Thingol.Class _) = namify_class

       | namify_stmt (Code_Thingol.Classrel _) = namify_object

       | namify_stmt (Code_Thingol.Classparam _) = namify_object

       | namify_stmt (Code_Thingol.Classinst _) = namify_common false;

     fun make_declarations nsps (implicits, nodes) =

       let

         val (module_fragments, stmt_names) = List.partition

           (fn name_fragment => case Graph.get_node nodes name_fragment

             of (_, Module _) => true | _ => false) (Graph.keys nodes);

         fun modify_stmt (Stmt (Code_Thingol.Datatypecons _)) = Dummy

           | modify_stmt (Stmt (Code_Thingol.Classrel _)) = Dummy

           | modify_stmt (Stmt (Code_Thingol.Classparam _)) = Dummy

           | modify_stmt stmt = stmt;

         fun declare namify modify name (nsps, nodes) =

           let

             val (base, node) = Graph.get_node nodes name;

             val (base', nsps') = namify node base nsps;

             val nodes' = Graph.map_node name (K (base', modify node)) nodes;

           in (nsps', nodes') end;

         val (nsps', nodes') = (nsps, nodes)

           |> fold (declare (K namify_module) I) module_fragments

           |> fold (declare (namify_stmt o (fn Stmt stmt => stmt)) modify_stmt) stmt_names;

         val nodes'' = nodes'

           |> fold (fn name_fragment => (Graph.map_node name_fragment

               o apsnd o map_module) (make_declarations nsps')) module_fragments;

       in (implicits, nodes'') end;

     val (_, sca_program) = make_declarations ((reserved, reserved), reserved) proto_program;

     (* deresolving *)

     fun deresolver prefix_fragments name =

       let

         val (name_fragments, _) = dest_name name;

         val (_, (_, remainder)) = chop_prefix (op =) (prefix_fragments, name_fragments);

         val nodes = fold (fn name_fragment => fn nodes => case Graph.get_node nodes name_fragment

          of (_, Module (_, nodes)) => nodes) name_fragments sca_program;

         val (base', _) = Graph.get_node nodes name;

       in Long_Name.implode (remainder @ [base']) end

         handle Graph.UNDEF _ => error ("Unknown statement name: " ^ labelled_name name);

   in (deresolver, sca_program) end;

 fun serialize_scala labelled_name raw_reserved includes module_alias

     _ syntax_tyco syntax_const

     program (stmt_names, presentation_stmt_names) =

   let

     (* build program *)

     val reserved = fold (insert (op =) o fst) includes raw_reserved;

     val (deresolver, sca_program) = scala_program_of_program labelled_name

       (Name.make_context reserved) module_alias program;

     (* print statements *)

     fun lookup_constr tyco constr = case Graph.get_node program tyco

      of Code_Thingol.Datatype (_, (_, constrs)) =>

           the (AList.lookup (op = o apsnd fst) constrs constr);

     fun classparams_of_class class = case Graph.get_node program class

      of Code_Thingol.Class (_, (_, (_, classparams))) => classparams;

     fun args_num c = case Graph.get_node program c

      of Code_Thingol.Fun (_, (((_, ty), []), _)) =>

           (length o fst o Code_Thingol.unfold_fun) ty

       | Code_Thingol.Fun (_, ((_, ((ts, _), _) :: _), _)) => length ts

       | Code_Thingol.Datatypecons (_, tyco) => length (lookup_constr tyco c)

       | Code_Thingol.Classparam (_, class) =>

           (length o fst o Code_Thingol.unfold_fun o the o AList.lookup (op =)

             (classparams_of_class class)) c;

     fun is_singleton_constr c = case Graph.get_node program c

      of Code_Thingol.Datatypecons (_, tyco) => null (lookup_constr tyco c)

       | _ => false;

     val print_stmt = print_scala_stmt labelled_name syntax_tyco syntax_const

       (make_vars reserved) args_num is_singleton_constr;

     (* print nodes *)

     fun print_module base implicit_ps p = Pretty.chunks2

       ([str ("object " ^ base ^ " {")]

         @ (if null implicit_ps then [] else (single o Pretty.block)

             (str "import /*implicits*/" :: Pretty.brk 1 :: commas implicit_ps))

         @ [p, str ("} /* object " ^ base ^ " */")]);

     fun print_implicit prefix_fragments implicit =

       let

         val s = deresolver prefix_fragments implicit;

       in if length (Long_Name.explode s) = 1 then NONE else SOME (str s) end;

     fun print_node _ (_, Dummy) = NONE

       | print_node prefix_fragments (name, Stmt stmt) =

           if null presentation_stmt_names

           orelse member (op =) presentation_stmt_names name

           then SOME (print_stmt (deresolver prefix_fragments, deresolver []) (name, stmt))

           else NONE

       | print_node prefix_fragments (name_fragment, Module (implicits, nodes)) =

           if null presentation_stmt_names

           then

             let

               val prefix_fragments' = prefix_fragments @ [name_fragment];

             in

               Option.map (print_module name_fragment

                 (map_filter (print_implicit prefix_fragments') implicits))

                   (print_nodes prefix_fragments' nodes)

             end

           else print_nodes [] nodes

     and print_nodes prefix_fragments nodes = let

         val ps = map_filter (fn name => print_node prefix_fragments (name,

           snd (Graph.get_node nodes name)))

             ((rev o flat o Graph.strong_conn) nodes);

       in if null ps then NONE else SOME (Pretty.chunks2 ps) end;

     (* serialization *)

     val p_includes = if null presentation_stmt_names

       then map (fn (base, p) => print_module base [] p) includes else [];

     val p = Pretty.chunks2 (p_includes @ the_list (print_nodes [] sca_program));

     fun write width NONE = writeln_pretty width

       | write width (SOME p) = File.write p o string_of_pretty width;

   in

     Code_Target.serialization write (rpair [] oo string_of_pretty) p

   end;

 end; (*local*)

 val literals = let

   fun char_scala c = if c = "'" then "\\'"

     else if c = "\"" then "\\\""

     else if c = "\\" then "\\\\"

     else let val k = ord c

     in if k < 32 orelse k > 126 then "\\" ^ radixstring (8, "0", k) else c end

   fun numeral_scala k = if k < 0

     then if k > ~ 2147483647 then "- " ^ string_of_int (~ k)

       else quote ("- " ^ string_of_int (~ k))

     else if k <= 2147483647 then string_of_int k

       else quote (string_of_int k)

 in Literals {

   literal_char = Library.enclose "'" "'" o char_scala,

   literal_string = quote o translate_string char_scala,

   literal_numeral = fn k => "BigInt(" ^ numeral_scala k ^ ")",

   literal_positive_numeral = fn k => "Nat.Nat(" ^ numeral_scala k ^ ")",

   literal_alternative_numeral = fn k => "Natural.Nat(" ^ numeral_scala k ^ ")",

   literal_naive_numeral = fn k => "BigInt(" ^ numeral_scala k ^ ")",

   literal_list = fn [] => str "Nil" | ps => Pretty.block [str "List", enum "," "(" ")" ps],

   infix_cons = (6, "::")

 } end;

 (** Isar setup **)

 fun isar_serializer _ =

   Code_Target.parse_args (Scan.succeed ())

   #> (fn () => serialize_scala);

 val setup =

   Code_Target.add_target

     (target, { serializer = isar_serializer, literals = literals,

       check = { env_var = "SCALA_HOME", make_destination = fn p => Path.append p (Path.explode "ROOT.scala"),

         make_command = fn scala_home => fn _ =>

           "export JAVA_OPTS='-Xms128m -Xmx512m -Xss2m' && "

             ^ Path.implode (Path.append (Path.explode scala_home) (Path.explode "bin/scalac")) ^ " ROOT.scala" } })

   #> Code_Target.add_syntax_tyco target "fun"

      (SOME (2, fn print_typ => fn fxy => fn [ty1, ty2] =>

         brackify_infix (1, R) fxy (

           print_typ BR ty1 (*product type vs. tupled arguments!*),

           str "=>",

           print_typ (INFX (1, R)) ty2

         )))

   #> fold (Code_Target.add_reserved target) [

       "abstract", "case", "catch", "class", "def", "do", "else", "extends", "false",

       "final", "finally", "for", "forSome", "if", "implicit", "import", "lazy",

       "match", "new", "null", "object", "override", "package", "private", "protected",

       "requires", "return", "sealed", "super", "this", "throw", "trait", "try",

       "true", "type", "val", "var", "while", "with", "yield"

     ]

   #> fold (Code_Target.add_reserved target) [

       "apply", "error", "BigInt", "Nil", "List"

     ];

 end; (*struct*)