(*  Title:      Tools/Code/code_target.ML

     Author:     Florian Haftmann, TU Muenchen

 Generic infrastructure for target language data.

 *)

 signature CODE_TARGET =

 sig

   val cert_tyco: theory -> string -> string

   val read_tyco: theory -> string -> string

   val export_code_for: theory -> Path.T option -> string -> int option -> string option -> Token.T list

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

   val produce_code_for: theory -> string -> int option -> string option -> Token.T list

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

   val check_code_for: theory -> string -> bool -> Token.T list

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

   val export_code: theory -> string list

     -> (((string * string option) * Path.T option) * Token.T list) list -> unit

   val produce_code: theory -> string list -> (Code_Thingol.naming -> string list)

     -> string -> int option -> string option -> Token.T list -> string * string option list

   val check_code: theory -> string list

     -> ((string * bool) * Token.T list) list -> unit

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

   type serializer

   type literals = Code_Printer.literals

   val add_target: string * { serializer: serializer, literals: literals,

     check: { env_var: string, make_destination: Path.T -> Path.T,

       make_command: string -> string -> string } } -> theory -> theory

   val extend_target: string *

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

     -> theory -> theory

   val assert_target: theory -> string -> string

   val the_literals: theory -> string -> literals

   type serialization

   val parse_args: 'a parser -> Token.T list -> 'a

   val serialization: (int -> Path.T option -> 'a -> unit)

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

     -> 'a -> serialization

   val set_default_code_width: int -> theory -> theory

   val allow_abort: string -> theory -> theory

   type tyco_syntax = Code_Printer.tyco_syntax

   type const_syntax = Code_Printer.const_syntax

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

   val add_instance_syntax: string -> class * string -> unit option -> theory -> theory

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

   val add_const_syntax: string -> string -> const_syntax option -> theory -> theory

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

   val add_include: string -> string * (string * string list) option -> theory -> theory

 end;

 structure Code_Target : CODE_TARGET =

 struct

 open Basic_Code_Thingol;

 type literals = Code_Printer.literals;

 type tyco_syntax = Code_Printer.tyco_syntax;

 type const_syntax = Code_Printer.const_syntax;

 (** abstract nonsense **)

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

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

 fun stmt_names_of_destination (String stmt_names) = stmt_names

   | stmt_names_of_destination _ = [];

 fun serialization output _ content width (File some_path) = (output width some_path content; NONE)

   | serialization _ string content width (String _) = SOME (string width content);

 fun file some_path f = (f (File some_path); ());

 fun string stmt_names f = the (f (String stmt_names));

 (** theory data **)

 datatype symbol_syntax_data = Symbol_Syntax_Data of {

   class: string Symtab.table,

   instance: unit Symreltab.table,

   tyco: Code_Printer.tyco_syntax Symtab.table,

   const: Code_Printer.const_syntax Symtab.table

 };

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

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

 fun map_symbol_syntax_data f (Symbol_Syntax_Data { class, instance, tyco, const }) =

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

 fun merge_symbol_syntax_data

   (Symbol_Syntax_Data { class = class1, instance = instance1, tyco = tyco1, const = const1 },

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

   make_symbol_syntax_data (

     (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 = Token.T list (*arguments*) -> {

     labelled_name: string -> string,

     reserved_syms: string list,

     includes: (string * Pretty.T) list,

     single_module: bool,

     module_alias: string -> string option,

     class_syntax: string -> string option,

     tyco_syntax: string -> Code_Printer.tyco_syntax option,

     const_syntax: string -> Code_Printer.activated_const_syntax option,

     program: Code_Thingol.program,

     names: string list,

     presentation_names: string list }

   -> serialization;

 datatype description = Fundamental of { serializer: serializer,

       literals: literals,

       check: { env_var: string, make_destination: Path.T -> Path.T,

         make_command: string -> string -> string } }

   | Extension of string *

       (Code_Thingol.naming -> Code_Thingol.program -> Code_Thingol.program);

 datatype target = Target of {

   serial: serial,

   description: description,

   reserved: string list,

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

   module_alias: string Symtab.table,

   symbol_syntax: symbol_syntax_data

 };

 fun make_target ((serial, description), ((reserved, includes), (module_alias, symbol_syntax))) =

   Target { serial = serial, description = description, reserved = reserved, 

     includes = includes, module_alias = module_alias, symbol_syntax = symbol_syntax };

 fun map_target f ( Target { serial, description, reserved, includes, module_alias, symbol_syntax } ) =

   make_target (f ((serial, description), ((reserved, includes), (module_alias, symbol_syntax))));

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

   reserved = reserved1, includes = includes1,

   module_alias = module_alias1, symbol_syntax = symbol_syntax1 },

     Target { serial = serial2, description = _,

       reserved = reserved2, includes = includes2,

       module_alias = module_alias2, symbol_syntax = symbol_syntax2 }) =

   if serial1 = serial2 orelse not strict then

     make_target ((serial1, description),

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

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

           merge_symbol_syntax_data (symbol_syntax1, symbol_syntax2))

     ))

   else

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

 fun the_description (Target { description, ... }) = description;

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

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

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

 fun the_symbol_syntax (Target { symbol_syntax = Symbol_Syntax_Data x, ... }) = x;

 structure Targets = Theory_Data

 (

   type T = (target Symtab.table * string list) * int;

   val empty = ((Symtab.empty, []), 80);

   val extend = I;

   fun merge (((target1, exc1), width1), ((target2, exc2), width2)) : T =

     ((Symtab.join (merge_target true) (target1, target2),

       Library.merge (op =) (exc1, exc2)), Int.max (width1, width2));

 );

 val abort_allowed = snd o fst o Targets.get;

 fun assert_target thy target = if Symtab.defined ((fst o fst) (Targets.get thy)) target

   then target

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

 fun put_target (target, seri) thy =

   let

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

     val _ = case seri

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

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

       | _ => ();

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

      of NONE => false

       | SOME (Extension _) => true

       | SOME (Fundamental _) => (case seri

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

           | _ => true);

     val _ = if overwriting

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

       else (); 

   in

     thy

     |> (Targets.map o apfst o apfst o Symtab.update)

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

             (Symtab.empty, make_symbol_syntax_data ((Symtab.empty, Symreltab.empty),

               (Symtab.empty, Symtab.empty))))))

   end;

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

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

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

 fun map_target_data target f thy =

   let

     val _ = assert_target thy target;

   in

     thy

     |> (Targets.map o apfst 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_module_alias target =

   map_target_data target o apsnd o apsnd o apfst;

 fun map_symbol_syntax target =

   map_target_data target o apsnd o apsnd o apsnd o map_symbol_syntax_data;

 fun set_default_code_width k = (Targets.map o apsnd) (K k);

 (** serializer usage **)

 (* montage *)

 fun the_fundamental thy =

   let

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

     fun fundamental target = case Symtab.lookup targets target

      of SOME data => (case the_description data

          of Fundamental data => data

           | Extension (super, _) => fundamental super)

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

   in fundamental end;

 fun the_literals thy = #literals o the_fundamental thy;

 local

 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 c => fn (tab, naming) =>

       case Code_Thingol.lookup_const naming c

        of SOME name => let

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

                 literals c (the (Symtab.lookup src_tab c)) 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_name args naming program2 (names1, presentation_names) width =

   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 args {

       labelled_name = Code_Thingol.labelled_name thy program2,

       reserved_syms = reserved,

       includes = includes,

       single_module = is_some module_name,

       module_alias = if is_some module_name then K module_name else Symtab.lookup module_alias,

       class_syntax = Symtab.lookup class',

       tyco_syntax = Symtab.lookup tyco',

       const_syntax = Symtab.lookup const',

       program = program3,

       names = names1,

       presentation_names = presentation_names } width

   end;

 fun mount_serializer thy target some_width raw_module_name args naming program names destination =

   let

     val ((targets, abortable), default_width) = Targets.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_description data

        of Fundamental _ => (I, data)

         | Extension (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 = case the_description data

     of Fundamental seri => #serializer seri;

     val presentation_names = stmt_names_of_destination destination;

     val module_name = if null presentation_names

       then raw_module_name else SOME "Code";

     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_symbol_syntax data;

     val literals = the_literals thy target;

     val width = the_default default_width some_width;

   in

     invoke_serializer thy abortable serializer literals reserved

       includes module_alias class instance tyco const module_name args

         naming (modify program) (names, presentation_names) width destination

   end;

 in

 fun export_code_for thy some_path target some_width some_module_name args naming program names =

   file some_path (mount_serializer thy target some_width some_module_name args naming program names);

 fun produce_code_for thy target some_width some_module_name args naming program (names, selects) =

   string selects (mount_serializer thy target some_width some_module_name args naming program names);

 fun check_code_for thy target strict args naming program names_cs =

   let

     val module_name = "Code_Test";

     val { env_var, make_destination, make_command } =

       (#check o the_fundamental thy) target;

     val env_param = getenv env_var;

     fun ext_check env_param p =

       let 

         val destination = make_destination p;

         val _ = file (SOME destination) (mount_serializer thy target (SOME 80)

           (SOME module_name) args naming program names_cs);

         val cmd = make_command env_param module_name;

       in if bash ("cd " ^ File.shell_path p ^ " && " ^ cmd ^ " 2>&1") <> 0

         then error ("Code check failed for " ^ target ^ ": " ^ cmd)

         else ()

       end;

   in if env_param = ""

     then if strict

       then error (env_var ^ " not set; cannot check code for " ^ target)

       else warning (env_var ^ " not set; skipped checking code for " ^ target)

     else Cache_IO.with_tmp_dir "Code_Test" (ext_check env_param)

   end;

 end; (* local *)

 (* 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 (names2, (naming, program)) = Code_Thingol.consts_program thy true cs2;

     val names3 = transitivly_non_empty_funs thy naming program;

     val cs3 = map_filter (fn (c, name) =>

       if member (op =) names3 name then SOME c else NONE) (cs2 ~~ names2);

   in union (op =) cs3 cs1 end;

 fun prep_destination "" = NONE

   | prep_destination "-" = NONE

   | prep_destination s = SOME (Path.explode s);

 fun export_code thy cs seris =

   let

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

     val _ = map (fn (((target, module_name), some_path), args) =>

       export_code_for thy some_path target NONE module_name args naming program names_cs) seris;

   in () end;

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

   ((map o apfst o apsnd) prep_destination seris);

 fun produce_code thy cs names_stmt target some_width some_module_name args =

   let

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

   in produce_code_for thy target some_width some_module_name args naming program (names_cs, names_stmt naming) end;

 fun check_code thy cs seris =

   let

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

     val _ = map (fn ((target, strict), args) =>

       check_code_for thy target strict args naming program names_cs) seris;

   in () end;

 fun check_code_cmd raw_cs seris thy = check_code thy (read_const_exprs thy raw_cs) seris;

 (** serializer configuration **)

 (* data access *)

 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 cert_inst thy (class, tyco) =

   (cert_class thy class, cert_tyco thy tyco);

 fun read_inst thy (raw_tyco, raw_class) =

   (read_class thy raw_class, read_tyco thy raw_tyco);

 fun gen_add_syntax (mapp, upd, del) prep_x prep_syn target raw_x some_raw_syn thy =

   let

     val x = prep_x thy raw_x;

     val change = case some_raw_syn

      of SOME raw_syn => upd (x, prep_syn thy x raw_syn)

       | NONE => del x;

   in (map_symbol_syntax target o mapp) change thy end;

 fun gen_add_class_syntax prep_class =

   gen_add_syntax (apfst o apfst, Symtab.update, Symtab.delete_safe) prep_class ((K o K) I);

 fun gen_add_instance_syntax prep_inst =

   gen_add_syntax (apfst o apsnd, Symreltab.update, Symreltab.delete_safe) prep_inst ((K o K) I);

 fun gen_add_tyco_syntax prep_tyco =

   gen_add_syntax (apsnd o apfst, Symtab.update, Symtab.delete_safe) prep_tyco

     (fn thy => fn tyco => fn syn => if fst syn <> Sign.arity_number thy tyco

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

       else syn);

 fun gen_add_const_syntax prep_const =

   gen_add_syntax (apsnd o apsnd, Symtab.update, Symtab.delete_safe) prep_const

     (fn thy => fn c => fn syn =>

       if Code_Printer.requires_args syn > Code.args_number thy c

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

       else syn);

 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, (Code_Printer.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 (K I);

 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 |> (Targets.map o apfst o apsnd) (insert (op =) c) end;

 (* concrete syntax *)

 local

 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)));

 fun process_multi_syntax parse_thing parse_syntax change =

   (Parse.and_list1 parse_thing

   :|-- (fn things => Scan.repeat1 (Parse.$$$ "(" |-- Parse.name --

         (zip_list things parse_syntax (Parse.$$$ "and")) --| Parse.$$$ ")")))

   >> (Toplevel.theory oo fold)

     (fn (target, syns) => fold (fn (raw_x, syn) => change target raw_x syn) syns);

 in

 val add_class_syntax = gen_add_class_syntax cert_class;

 val add_instance_syntax = gen_add_instance_syntax cert_inst;

 val add_tyco_syntax = gen_add_tyco_syntax cert_tyco;

 val add_const_syntax = gen_add_const_syntax (K I);

 val allow_abort = gen_allow_abort (K I);

 val add_reserved = add_reserved;

 val add_include = add_include;

 val add_class_syntax_cmd = gen_add_class_syntax read_class;

 val add_instance_syntax_cmd = gen_add_instance_syntax read_inst;

 val add_tyco_syntax_cmd = gen_add_tyco_syntax read_tyco;

 val add_const_syntax_cmd = gen_add_const_syntax Code.read_const;

 val allow_abort_cmd = gen_allow_abort Code.read_const;

 fun parse_args f args =

   case Scan.read Token.stopper f args

    of SOME x => x

     | NONE => error "Bad serializer arguments";

 (** Isar setup **)

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

 val code_expr_argsP = Scan.optional (Parse.$$$ "(" |-- Args.parse --| Parse.$$$ ")") [];

 val code_exprP =

   Scan.repeat1 Parse.term_group :|-- (fn raw_cs =>

     ((Parse.$$$ checkingK |-- Scan.repeat (Parse.name

       -- ((Parse.$$$ "?" |-- Scan.succeed false) || Scan.succeed true) -- code_expr_argsP))

       >> (fn seris => check_code_cmd raw_cs seris)

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

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

        -- Scan.optional (Parse.$$$ fileK |-- Parse.name) ""

        -- code_expr_argsP) >> (fn seris => export_code_cmd raw_cs seris)));

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

 val _ =

   Outer_Syntax.command "code_class" "define code syntax for class" Keyword.thy_decl (

     process_multi_syntax Parse.xname (Scan.option Parse.string)

     add_class_syntax_cmd);

 val _ =

   Outer_Syntax.command "code_instance" "define code syntax for instance" Keyword.thy_decl (

     process_multi_syntax (Parse.xname --| Parse.$$$ "::" -- Parse.xname)

       (Scan.option (Parse.minus >> K ()))

     add_instance_syntax_cmd);

 val _ =

   Outer_Syntax.command "code_type" "define code syntax for type constructor" Keyword.thy_decl (

     process_multi_syntax Parse.xname Code_Printer.parse_tyco_syntax

     add_tyco_syntax_cmd);

 val _ =

   Outer_Syntax.command "code_const" "define code syntax for constant" Keyword.thy_decl (

     process_multi_syntax Parse.term_group Code_Printer.parse_const_syntax

     add_const_syntax_cmd);

 val _ =

   Outer_Syntax.command "code_reserved" "declare words as reserved for target language"

     Keyword.thy_decl (

     Parse.name -- Scan.repeat1 Parse.name

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

   );

 val _ =

   Outer_Syntax.command "code_include" "declare piece of code to be included in generated code"

     Keyword.thy_decl (

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

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

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

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

   );

 val _ =

   Outer_Syntax.command "code_modulename" "alias module to other name" Keyword.thy_decl (

     Parse.name -- Scan.repeat1 (Parse.name -- Parse.name)

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

   );

 val _ =

   Outer_Syntax.command "code_abort" "permit constant to be implemented as program abort"

     Keyword.thy_decl (

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

   );

 val _ =

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

     Keyword.diag (Parse.!!! 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 Token.stopper (Parse.!!! code_exprP)

     ((filter Token.is_proper o Outer_Syntax.scan Position.none) cmd)

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

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

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

 end; (*local*)

 end; (*struct*)