(*  Title:      Tools/code/code_target.ML

     Author:     Florian Haftmann, TU Muenchen

 Serializer from intermediate language ("Thin-gol") to target languages.

 *)

 signature CODE_TARGET =

 sig

   include CODE_PRINTER

   type serializer

   val add_target: string * (serializer * literals) -> theory -> theory

   val extend_target: string *

       (string * (Code_Thingol.naming -> Code_Thingol.program -> Code_Thingol.program))

     -> theory -> theory

   val assert_target: theory -> string -> string

   type destination

   type serialization

   val parse_args: (OuterLex.token list -> 'a * OuterLex.token list)

     -> OuterLex.token list -> 'a

   val stmt_names_of_destination: destination -> string list

   val code_of_pretty: Pretty.T -> string

   val code_writeln: Pretty.T -> unit

   val mk_serialization: string -> ('a -> unit) option

     -> (Path.T option -> 'a -> unit)

     -> ('a -> string * string option list)

     -> 'a -> serialization

   val serialize: theory -> string -> string option -> OuterLex.token list

     -> Code_Thingol.naming -> Code_Thingol.program -> string list -> serialization

   val serialize_custom: theory -> string * (serializer * literals)

     -> Code_Thingol.naming -> Code_Thingol.program -> string list -> string * string option list

   val the_literals: theory -> string -> literals

   val compile: serialization -> unit

   val export: serialization -> unit

   val file: Path.T -> serialization -> unit

   val string: string list -> serialization -> string

   val code_of: theory -> string -> string

     -> string list -> (Code_Thingol.naming -> string list) -> string

   val shell_command: string (*theory name*) -> string (*export_code expr*) -> unit

   val code_width: int Unsynchronized.ref

   val allow_abort: string -> theory -> theory

   val add_syntax_class: string -> class -> string option -> theory -> theory

   val add_syntax_inst: string -> string * class -> bool -> theory -> theory

   val add_syntax_tyco: string -> string -> tyco_syntax option -> theory -> theory

   val add_syntax_const: string -> string -> proto_const_syntax option -> theory -> theory

   val add_reserved: string -> string -> theory -> theory

 end;

 structure Code_Target : CODE_TARGET =

 struct

 open Basic_Code_Thingol;

 open Code_Printer;

 (** basics **)

 datatype destination = Compile | Export | File of Path.T | String of string list;

 type serialization = destination -> (string * string option list) option;

 val code_width = Unsynchronized.ref 80; (*FIXME after Pretty module no longer depends on print mode*)

 fun code_setmp f = PrintMode.setmp [] (Pretty.setmp_margin (!code_width) f);

 fun code_of_pretty p = code_setmp Pretty.string_of p ^ "\n";

 fun code_writeln p = Pretty.setmp_margin (!code_width) Pretty.writeln p;

 (*FIXME why another code_setmp?*)

 fun compile f = (code_setmp f Compile; ());

 fun export f = (code_setmp f Export; ());

 fun file p f = (code_setmp f (File p); ());

 fun string stmts f = fst (the (code_setmp f (String stmts)));

 fun stmt_names_of_destination (String stmts) = stmts

   | stmt_names_of_destination _ = [];

 fun mk_serialization target (SOME comp) _ _ code Compile = (comp code; NONE)

   | mk_serialization target NONE _ _ _ Compile = error (target ^ ": no internal compilation")

   | mk_serialization target _ output _ code Export = (output NONE code ; NONE)

   | mk_serialization target _ output _ code (File file) = (output (SOME file) code; NONE)

   | mk_serialization target _ _ string code (String _) = SOME (string code);

 (** theory data **)

 datatype name_syntax_table = NameSyntaxTable of {

   class: string Symtab.table,

   instance: unit Symreltab.table,

   tyco: tyco_syntax Symtab.table,

   const: proto_const_syntax Symtab.table

 };

 fun mk_name_syntax_table ((class, instance), (tyco, const)) =

   NameSyntaxTable { class = class, instance = instance, tyco = tyco, const = const };

 fun map_name_syntax_table f (NameSyntaxTable { class, instance, tyco, const }) =

   mk_name_syntax_table (f ((class, instance), (tyco, const)));

 fun merge_name_syntax_table (NameSyntaxTable { class = class1, instance = instance1, tyco = tyco1, const = const1 },

     NameSyntaxTable { class = class2, instance = instance2, tyco = tyco2, const = const2 }) =

   mk_name_syntax_table (

     (Symtab.join (K snd) (class1, class2),

        Symreltab.join (K snd) (instance1, instance2)),

     (Symtab.join (K snd) (tyco1, tyco2),

        Symtab.join (K snd) (const1, const2))

   );

 type serializer =

   string option                         (*module name*)

   -> OuterLex.token list                (*arguments*)

   -> (string -> string)                 (*labelled_name*)

   -> string list                        (*reserved symbols*)

   -> (string * Pretty.T) list           (*includes*)

   -> (string -> string option)          (*module aliasses*)

   -> (string -> string option)          (*class syntax*)

   -> (string -> tyco_syntax option)

   -> (string -> const_syntax option)

   -> Code_Thingol.program

   -> string list                        (*selected statements*)

   -> serialization;

 datatype serializer_entry = Serializer of serializer * literals

   | Extends of string * (Code_Thingol.naming -> Code_Thingol.program -> Code_Thingol.program);

 datatype target = Target of {

   serial: serial,

   serializer: serializer_entry,

   reserved: string list,

   includes: (Pretty.T * string list) Symtab.table,

   name_syntax_table: name_syntax_table,

   module_alias: string Symtab.table

 };

 fun make_target ((serial, serializer), ((reserved, includes), (name_syntax_table, module_alias))) =

   Target { serial = serial, serializer = serializer, reserved = reserved, 

     includes = includes, name_syntax_table = name_syntax_table, module_alias = module_alias };

 fun map_target f ( Target { serial, serializer, reserved, includes, name_syntax_table, module_alias } ) =

   make_target (f ((serial, serializer), ((reserved, includes), (name_syntax_table, module_alias))));

 fun merge_target strict target (Target { serial = serial1, serializer = serializer,

   reserved = reserved1, includes = includes1,

   name_syntax_table = name_syntax_table1, module_alias = module_alias1 },

     Target { serial = serial2, serializer = _,

       reserved = reserved2, includes = includes2,

       name_syntax_table = name_syntax_table2, module_alias = module_alias2 }) =

   if serial1 = serial2 orelse not strict then

     make_target ((serial1, serializer),

       ((merge (op =) (reserved1, reserved2), Symtab.merge (op =) (includes1, includes2)),

         (merge_name_syntax_table (name_syntax_table1, name_syntax_table2),

           Symtab.join (K snd) (module_alias1, module_alias2))

     ))

   else

     error ("Incompatible serializers: " ^ quote target);

 structure CodeTargetData = TheoryDataFun

 (

   type T = target Symtab.table * string list;

   val empty = (Symtab.empty, []);

   val copy = I;

   val extend = I;

   fun merge _ ((target1, exc1) : T, (target2, exc2)) =

     (Symtab.join (merge_target true) (target1, target2), Library.merge (op =) (exc1, exc2));

 );

 fun the_serializer (Target { serializer, ... }) = serializer;

 fun the_reserved (Target { reserved, ... }) = reserved;

 fun the_includes (Target { includes, ... }) = includes;

 fun the_name_syntax (Target { name_syntax_table = NameSyntaxTable x, ... }) = x;

 fun the_module_alias (Target { module_alias , ... }) = module_alias;

 val abort_allowed = snd o CodeTargetData.get;

 fun assert_target thy target =

   case Symtab.lookup (fst (CodeTargetData.get thy)) target

    of SOME data => target

     | NONE => error ("Unknown code target language: " ^ quote target);

 fun put_target (target, seri) thy =

   let

     val lookup_target = Symtab.lookup (fst (CodeTargetData.get thy));

     val _ = case seri

      of Extends (super, _) => if is_some (lookup_target super) then ()

           else error ("Unknown code target language: " ^ quote super)

       | _ => ();

     val overwriting = case (Option.map the_serializer o lookup_target) target

      of NONE => false

       | SOME (Extends _) => true

       | SOME (Serializer _) => (case seri

          of Extends _ => error ("Will not overwrite existing target " ^ quote target)

           | _ => true);

     val _ = if overwriting

       then warning ("Overwriting existing target " ^ quote target)

       else (); 

   in

     thy

     |> (CodeTargetData.map o apfst oo Symtab.map_default)

           (target, make_target ((serial (), seri), (([], Symtab.empty),

             (mk_name_syntax_table ((Symtab.empty, Symreltab.empty), (Symtab.empty, Symtab.empty)),

               Symtab.empty))))

           ((map_target o apfst o apsnd o K) seri)

   end;

 fun add_target (target, seri) = put_target (target, Serializer seri);

 fun extend_target (target, (super, modify)) =

   put_target (target, Extends (super, modify));

 fun map_target_data target f thy =

   let

     val _ = assert_target thy target;

   in

     thy

     |> (CodeTargetData.map o apfst o Symtab.map_entry target o map_target) f

   end;

 fun map_reserved target =

   map_target_data target o apsnd o apfst o apfst;

 fun map_includes target =

   map_target_data target o apsnd o apfst o apsnd;

 fun map_name_syntax target =

   map_target_data target o apsnd o apsnd o apfst o map_name_syntax_table;

 fun map_module_alias target =

   map_target_data target o apsnd o apsnd o apsnd;

 (** serializer configuration **)

 (* data access *)

 local

 fun cert_class thy class =

   let

     val _ = AxClass.get_info thy class;

   in class end;

 fun read_class thy = cert_class thy o Sign.intern_class thy;

 fun cert_tyco thy tyco =

   let

     val _ = if Sign.declared_tyname thy tyco then ()

       else error ("No such type constructor: " ^ quote tyco);

   in tyco end;

 fun read_tyco thy = cert_tyco thy o Sign.intern_type thy;

 fun gen_add_syntax_class prep_class prep_const target raw_class raw_syn thy =

   let

     val class = prep_class thy raw_class;

   in case raw_syn

    of SOME syntax =>

       thy

       |> (map_name_syntax target o apfst o apfst)

            (Symtab.update (class, syntax))

     | NONE =>

       thy

       |> (map_name_syntax target o apfst o apfst)

            (Symtab.delete_safe class)

   end;

 fun gen_add_syntax_inst prep_class prep_tyco target (raw_tyco, raw_class) add_del thy =

   let

     val inst = (prep_class thy raw_class, prep_tyco thy raw_tyco);

   in if add_del then

     thy

     |> (map_name_syntax target o apfst o apsnd)

         (Symreltab.update (inst, ()))

   else

     thy

     |> (map_name_syntax target o apfst o apsnd)

         (Symreltab.delete_safe inst)

   end;

 fun gen_add_syntax_tyco prep_tyco target raw_tyco raw_syn thy =

   let

     val tyco = prep_tyco thy raw_tyco;

     fun check_args (syntax as (n, _)) = if n <> Sign.arity_number thy tyco

       then error ("Number of arguments mismatch in syntax for type constructor " ^ quote tyco)

       else syntax

   in case raw_syn

    of SOME syntax =>

       thy

       |> (map_name_syntax target o apsnd o apfst)

            (Symtab.update (tyco, check_args syntax))

     | NONE =>

       thy

       |> (map_name_syntax target o apsnd o apfst)

            (Symtab.delete_safe tyco)

   end;

 fun gen_add_syntax_const prep_const target raw_c raw_syn thy =

   let

     val c = prep_const thy raw_c;

     fun check_args (syntax as (n, _)) = if n > Code.args_number thy c

       then error ("Too many arguments in syntax for constant " ^ quote c)

       else syntax;

   in case raw_syn

    of SOME syntax =>

       thy

       |> (map_name_syntax target o apsnd o apsnd)

            (Symtab.update (c, check_args syntax))

     | NONE =>

       thy

       |> (map_name_syntax target o apsnd o apsnd)

            (Symtab.delete_safe c)

   end;

 fun add_reserved target =

   let

     fun add sym syms = if member (op =) syms sym

       then error ("Reserved symbol " ^ quote sym ^ " already declared")

       else insert (op =) sym syms

   in map_reserved target o add end;

 fun gen_add_include read_const target args thy =

   let

     fun add (name, SOME (content, raw_cs)) incls =

           let

             val _ = if Symtab.defined incls name

               then warning ("Overwriting existing include " ^ name)

               else ();

             val cs = map (read_const thy) raw_cs;

           in Symtab.update (name, (str content, cs)) incls end

       | add (name, NONE) incls = Symtab.delete name incls;

   in map_includes target (add args) thy end;

 val add_include = gen_add_include Code.check_const;

 val add_include_cmd = gen_add_include Code.read_const;

 fun add_module_alias target (thyname, modlname) =

   let

     val xs = Long_Name.explode modlname;

     val xs' = map (Name.desymbolize true) xs;

   in if xs' = xs

     then map_module_alias target (Symtab.update (thyname, modlname))

     else error ("Invalid module name: " ^ quote modlname ^ "\n"

       ^ "perhaps try " ^ quote (Long_Name.implode xs'))

   end;

 fun gen_allow_abort prep_const raw_c thy =

   let

     val c = prep_const thy raw_c;

   in thy |> (CodeTargetData.map o apsnd) (insert (op =) c) end;

 fun zip_list (x::xs) f g =

   f

   #-> (fn y =>

     fold_map (fn x => g |-- f >> pair x) xs

     #-> (fn xys => pair ((x, y) :: xys)));

 (* concrete syntax *)

 structure P = OuterParse

 and K = OuterKeyword

 fun parse_multi_syntax parse_thing parse_syntax =

   P.and_list1 parse_thing

   #-> (fn things => Scan.repeat1 (P.$$$ "(" |-- P.name --

         (zip_list things parse_syntax (P.$$$ "and")) --| P.$$$ ")"));

 in

 val add_syntax_class = gen_add_syntax_class cert_class (K I);

 val add_syntax_inst = gen_add_syntax_inst cert_class cert_tyco;

 val add_syntax_tyco = gen_add_syntax_tyco cert_tyco;

 val add_syntax_const = gen_add_syntax_const (K I);

 val allow_abort = gen_allow_abort (K I);

 val add_reserved = add_reserved;

 val add_syntax_class_cmd = gen_add_syntax_class read_class Code.read_const;

 val add_syntax_inst_cmd = gen_add_syntax_inst read_class read_tyco;

 val add_syntax_tyco_cmd = gen_add_syntax_tyco read_tyco;

 val add_syntax_const_cmd = gen_add_syntax_const Code.read_const;

 val allow_abort_cmd = gen_allow_abort Code.read_const;

 fun the_literals thy =

   let

     val (targets, _) = CodeTargetData.get thy;

     fun literals target = case Symtab.lookup targets target

      of SOME data => (case the_serializer data

          of Serializer (_, literals) => literals

           | Extends (super, _) => literals super)

       | NONE => error ("Unknown code target language: " ^ quote target);

   in literals end;

 (** serializer usage **)

 (* montage *)

 local

 fun labelled_name thy program name = case Graph.get_node program name

  of Code_Thingol.Fun (c, _) => quote (Code.string_of_const thy c)

   | Code_Thingol.Datatype (tyco, _) => "type " ^ quote (Sign.extern_type thy tyco)

   | Code_Thingol.Datatypecons (c, _) => quote (Code.string_of_const thy c)

   | Code_Thingol.Class (class, _) => "class " ^ quote (Sign.extern_class thy class)

   | Code_Thingol.Classrel (sub, super) => let

         val Code_Thingol.Class (sub, _) = Graph.get_node program sub

         val Code_Thingol.Class (super, _) = Graph.get_node program super

       in quote (Sign.extern_class thy sub ^ " < " ^ Sign.extern_class thy super) end

   | Code_Thingol.Classparam (c, _) => quote (Code.string_of_const thy c)

   | Code_Thingol.Classinst ((class, (tyco, _)), _) => let

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

         val Code_Thingol.Datatype (tyco, _) = Graph.get_node program tyco

       in quote (Sign.extern_type thy tyco ^ " :: " ^ Sign.extern_class thy class) end

 fun activate_syntax lookup_name src_tab = Symtab.empty

   |> fold_map (fn thing_identifier => fn tab => case lookup_name thing_identifier

        of SOME name => (SOME name,

             Symtab.update_new (name, the (Symtab.lookup src_tab thing_identifier)) tab)

         | NONE => (NONE, tab)) (Symtab.keys src_tab)

   |>> map_filter I;

 fun activate_const_syntax thy literals src_tab naming = (Symtab.empty, naming)

   |> fold_map (fn thing_identifier => fn (tab, naming) =>

       case Code_Thingol.lookup_const naming thing_identifier

        of SOME name => let

               val (syn, naming') = Code_Printer.activate_const_syntax thy

                 literals (the (Symtab.lookup src_tab thing_identifier)) naming

             in (SOME name, (Symtab.update_new (name, syn) tab, naming')) end

         | NONE => (NONE, (tab, naming))) (Symtab.keys src_tab)

   |>> map_filter I;

 fun invoke_serializer thy abortable serializer literals reserved abs_includes 

     module_alias class instance tyco const module args naming program2 names1 =

   let

     val (names_class, class') =

       activate_syntax (Code_Thingol.lookup_class naming) class;

     val names_inst = map_filter (Code_Thingol.lookup_instance naming)

       (Symreltab.keys instance);

     val (names_tyco, tyco') =

       activate_syntax (Code_Thingol.lookup_tyco naming) tyco;

     val (names_const, (const', _)) =

       activate_const_syntax thy literals const naming;

     val names_hidden = names_class @ names_inst @ names_tyco @ names_const;

     val names2 = subtract (op =) names_hidden names1;

     val program3 = Graph.subgraph (not o member (op =) names_hidden) program2;

     val names_all = Graph.all_succs program3 names2;

     val includes = abs_includes names_all;

     val program4 = Graph.subgraph (member (op =) names_all) program3;

     val empty_funs = filter_out (member (op =) abortable)

       (Code_Thingol.empty_funs program3);

     val _ = if null empty_funs then () else error ("No code equations for "

       ^ commas (map (Sign.extern_const thy) empty_funs));

   in

     serializer module args (labelled_name thy program2) reserved includes

       (Symtab.lookup module_alias) (Symtab.lookup class')

       (Symtab.lookup tyco') (Symtab.lookup const')

       program4 names2

   end;

 fun mount_serializer thy alt_serializer target module args naming program names =

   let

     val (targets, abortable) = CodeTargetData.get thy;

     fun collapse_hierarchy target =

       let

         val data = case Symtab.lookup targets target

          of SOME data => data

           | NONE => error ("Unknown code target language: " ^ quote target);

       in case the_serializer data

        of Serializer _ => (I, data)

         | Extends (super, modify) => let

             val (modify', data') = collapse_hierarchy super

           in (modify' #> modify naming, merge_target false target (data', data)) end

       end;

     val (modify, data) = collapse_hierarchy target;

     val (serializer, _) = the_default (case the_serializer data

      of Serializer seri => seri) alt_serializer;

     val reserved = the_reserved data;

     fun select_include names_all (name, (content, cs)) =

       if null cs then SOME (name, content)

       else if exists (fn c => case Code_Thingol.lookup_const naming c

        of SOME name => member (op =) names_all name

         | NONE => false) cs

       then SOME (name, content) else NONE;

     fun includes names_all = map_filter (select_include names_all)

       ((Symtab.dest o the_includes) data);

     val module_alias = the_module_alias data;

     val { class, instance, tyco, const } = the_name_syntax data;

     val literals = the_literals thy target;

   in

     invoke_serializer thy abortable serializer literals reserved

       includes module_alias class instance tyco const module args naming (modify program) names

   end;

 in

 fun serialize thy = mount_serializer thy NONE;

 fun serialize_custom thy (target_name, seri) naming program names =

   mount_serializer thy (SOME seri) target_name NONE [] naming program names (String [])

   |> the;

 end; (* local *)

 fun parse_args f args =

   case Scan.read OuterLex.stopper f args

    of SOME x => x

     | NONE => error "Bad serializer arguments";

 (* code presentation *)

 fun code_of thy target module_name cs names_stmt =

   let

     val (names_cs, (naming, program)) = Code_Thingol.consts_program thy cs;

   in

     string (names_stmt naming) (serialize thy target (SOME module_name) []

       naming program names_cs)

   end;

 (* code generation *)

 fun transitivly_non_empty_funs thy naming program =

   let

     val cs = subtract (op =) (abort_allowed thy) (Code_Thingol.empty_funs program);

     val names = map_filter (Code_Thingol.lookup_const naming) cs;

   in subtract (op =) (Graph.all_preds program names) (Graph.keys program) end;

 fun read_const_exprs thy cs =

   let

     val (cs1, cs2) = Code_Thingol.read_const_exprs thy cs;

     val (names3, (naming, program)) = Code_Thingol.consts_program thy cs2;

     val names4 = transitivly_non_empty_funs thy naming program;

     val cs5 = map_filter

       (fn (c, name) => if member (op =) names4 name then SOME c else NONE) (cs2 ~~ names3);

   in fold (insert (op =)) cs5 cs1 end;

 fun cached_program thy = 

   let

     val (naming, program) = Code_Thingol.cached_program thy;

   in (transitivly_non_empty_funs thy naming program, (naming, program)) end

 fun export_code thy cs seris =

   let

     val (cs', (naming, program)) = if null cs then cached_program thy

       else Code_Thingol.consts_program thy cs;

     fun mk_seri_dest dest = case dest

      of NONE => compile

       | SOME "-" => export

       | SOME f => file (Path.explode f)

     val _ = map (fn (((target, module), dest), args) =>

       (mk_seri_dest dest (serialize thy target module args naming program cs'))) seris;

   in () end;

 fun export_code_cmd raw_cs seris thy = export_code thy (read_const_exprs thy raw_cs) seris;

 (** Isar setup **)

 val (inK, module_nameK, fileK) = ("in", "module_name", "file");

 val code_exprP =

   (Scan.repeat P.term_group

   -- Scan.repeat (P.$$$ inK |-- P.name

      -- Scan.option (P.$$$ module_nameK |-- P.name)

      -- Scan.option (P.$$$ fileK |-- P.name)

      -- Scan.optional (P.$$$ "(" |-- Args.parse --| P.$$$ ")") []

   ) >> (fn (raw_cs, seris) => export_code_cmd raw_cs seris));

 val _ = List.app OuterKeyword.keyword [inK, module_nameK, fileK];

 val _ =

   OuterSyntax.command "code_class" "define code syntax for class" K.thy_decl (

     parse_multi_syntax P.xname (Scan.option P.string)

     >> (Toplevel.theory oo fold) (fn (target, syns) =>

           fold (fn (raw_class, syn) => add_syntax_class_cmd target raw_class syn) syns)

   );

 val _ =

   OuterSyntax.command "code_instance" "define code syntax for instance" K.thy_decl (

     parse_multi_syntax (P.xname --| P.$$$ "::" -- P.xname)

       ((P.minus >> K true) || Scan.succeed false)

     >> (Toplevel.theory oo fold) (fn (target, syns) =>

           fold (fn (raw_inst, add_del) => add_syntax_inst_cmd target raw_inst add_del) syns)

   );

 val _ =

   OuterSyntax.command "code_type" "define code syntax for type constructor" K.thy_decl (

     parse_multi_syntax P.xname (parse_syntax I)

     >> (Toplevel.theory oo fold) (fn (target, syns) =>

           fold (fn (raw_tyco, syn) => add_syntax_tyco_cmd target raw_tyco syn) syns)

   );

 val _ =

   OuterSyntax.command "code_const" "define code syntax for constant" K.thy_decl (

     parse_multi_syntax P.term_group (parse_syntax fst)

     >> (Toplevel.theory oo fold) (fn (target, syns) =>

       fold (fn (raw_const, syn) => add_syntax_const_cmd target raw_const

         (Code_Printer.simple_const_syntax syn)) syns)

   );

 val _ =

   OuterSyntax.command "code_reserved" "declare words as reserved for target language" K.thy_decl (

     P.name -- Scan.repeat1 P.name

     >> (fn (target, reserveds) => (Toplevel.theory o fold (add_reserved target)) reserveds)

   );

 val _ =

   OuterSyntax.command "code_include" "declare piece of code to be included in generated code" K.thy_decl (

     P.name -- P.name -- (P.text :|-- (fn "-" => Scan.succeed NONE

       | s => Scan.optional (P.$$$ "attach" |-- Scan.repeat1 P.term) [] >> pair s >> SOME))

     >> (fn ((target, name), content_consts) =>

         (Toplevel.theory o add_include_cmd target) (name, content_consts))

   );

 val _ =

   OuterSyntax.command "code_modulename" "alias module to other name" K.thy_decl (

     P.name -- Scan.repeat1 (P.name -- P.name)

     >> (fn (target, modlnames) => (Toplevel.theory o fold (add_module_alias target)) modlnames)

   );

 val _ =

   OuterSyntax.command "code_abort" "permit constant to be implemented as program abort" K.thy_decl (

     Scan.repeat1 P.term_group >> (Toplevel.theory o fold allow_abort_cmd)

   );

 val _ =

   OuterSyntax.command "export_code" "generate executable code for constants"

     K.diag (P.!!! code_exprP >> (fn f => Toplevel.keep (f o Toplevel.theory_of)));

 fun shell_command thyname cmd = Toplevel.program (fn _ =>

   (use_thy thyname; case Scan.read OuterLex.stopper (P.!!! code_exprP)

     ((filter OuterLex.is_proper o OuterSyntax.scan Position.none) cmd)

    of SOME f => (writeln "Now generating code..."; f (theory thyname))

     | NONE => error ("Bad directive " ^ quote cmd)))

   handle TOPLEVEL_ERROR => OS.Process.exit OS.Process.failure;

 end; (*local*)

 end; (*struct*)