(*  Title:      Tools/code/code_eval.ML

     Author:     Florian Haftmann, TU Muenchen

 Runtime services building on code generation into implementation language SML.

 *)

 signature CODE_EVAL =

 sig

   val target: string

   val eval: string option -> string * (unit -> 'a) option Unsynchronized.ref

     -> ((term -> term) -> 'a -> 'a) -> theory -> term -> string list -> 'a

   val evaluation_code: theory -> string -> string list -> string list

     -> string * ((string * string) list * (string * string) list)

   val setup: theory -> theory

 end;

 structure Code_Eval : CODE_EVAL =

 struct

 (** generic **)

 val target = "Eval";

 val eval_struct_name = "Code";

 fun evaluation_code thy struct_name_hint tycos consts =

   let

     val (consts', (naming, program)) = Code_Thingol.consts_program thy false consts;

     val tycos' = map (the o Code_Thingol.lookup_tyco naming) tycos;

     val struct_name = if struct_name_hint = "" then eval_struct_name

       else struct_name_hint;

     val (ml_code, target_names) = Code_ML.evaluation_code_of thy target

       struct_name naming program (consts' @ tycos');

     val (consts'', tycos'') = chop (length consts') target_names;

     val consts_map = map2 (fn const => fn NONE =>

         error ("Constant " ^ (quote o Code.string_of_const thy) const

           ^ "\nhas a user-defined serialization")

       | SOME const'' => (const, const'')) consts consts''

     val tycos_map = map2 (fn tyco => fn NONE =>

         error ("Type " ^ (quote o Sign.extern_type thy) tyco

           ^ "\nhas a user-defined serialization")

       | SOME tyco'' => (tyco, tyco'')) tycos tycos'';

   in (ml_code, (tycos_map, consts_map)) end;

 (** evaluation **)

 fun eval some_target reff postproc thy t args =

   let

     val ctxt = ProofContext.init_global thy;

     fun evaluator naming program ((_, (_, ty)), t) deps =

       let

         val _ = if Code_Thingol.contains_dictvar t then

           error "Term to be evaluated contains free dictionaries" else ();

         val value_name = "Value.VALUE.value"

         val program' = program

           |> Graph.new_node (value_name,

               Code_Thingol.Fun (Term.dummy_patternN, (([], ty), [(([], t), (NONE, true))])))

           |> fold (curry Graph.add_edge value_name) deps;

         val (value_code, [SOME value_name']) = Code_ML.evaluation_code_of thy

           (the_default target some_target) "" naming program' [value_name];

         val sml_code = "let\n" ^ value_code ^ "\nin " ^ value_name'

           ^ space_implode " " (map (enclose "(" ")") args) ^ " end";

       in ML_Context.evaluate ctxt false reff sml_code end;

   in Code_Thingol.eval thy postproc evaluator t end;

 (** instrumentalization by antiquotation **)

 local

 structure CodeAntiqData = Proof_Data

 (

   type T = (string list * string list) * (bool * (string

     * (string * ((string * string) list * (string * string) list)) lazy));

   fun init _ = (([], []), (true, ("", Lazy.value ("", ([], [])))));

 );

 val is_first_occ = fst o snd o CodeAntiqData.get;

 fun register_code new_tycos new_consts ctxt =

   let

     val ((tycos, consts), (_, (struct_name, _))) = CodeAntiqData.get ctxt;

     val tycos' = fold (insert (op =)) new_tycos tycos;

     val consts' = fold (insert (op =)) new_consts consts;

     val (struct_name', ctxt') = if struct_name = ""

       then ML_Antiquote.variant eval_struct_name ctxt

       else (struct_name, ctxt);

     val acc_code = Lazy.lazy

       (fn () => evaluation_code (ProofContext.theory_of ctxt) eval_struct_name tycos' consts');

   in CodeAntiqData.put ((tycos', consts'), (false, (struct_name', acc_code))) ctxt' end;

 fun register_const const = register_code [] [const];

 fun register_datatype tyco constrs = register_code [tyco] constrs;

 fun print_const const all_struct_name tycos_map consts_map =

   (Long_Name.append all_struct_name o the o AList.lookup (op =) consts_map) const;

 fun print_code is_first print_it ctxt =

   let

     val (_, (_, (struct_code_name, acc_code))) = CodeAntiqData.get ctxt;

     val (ml_code, (tycos_map, consts_map)) = Lazy.force acc_code;

     val ml_code = if is_first then ml_code

       else "";

     val all_struct_name = "Isabelle." ^ struct_code_name;

   in (ml_code, print_it all_struct_name tycos_map consts_map) end;

 in

 fun ml_code_antiq raw_const background =

   let

     val const = Code.check_const (ProofContext.theory_of background) raw_const;

     val is_first = is_first_occ background;

     val background' = register_const const background;

   in (print_code is_first (print_const const), background') end;

 end; (*local*)

 (** reflection support **)

 fun check_datatype thy tyco consts =

   let

     val constrs = (map fst o snd o Code.get_type thy) tyco;

     val missing_constrs = subtract (op =) consts constrs;

     val _ = if null missing_constrs then []

       else error ("Missing constructor(s) " ^ commas (map quote missing_constrs)

         ^ " for datatype " ^ quote tyco);

     val false_constrs = subtract (op =) constrs consts;

     val _ = if null false_constrs then []

       else error ("Non-constructor(s) " ^ commas (map quote false_constrs)

         ^ " for datatype " ^ quote tyco);

   in () end;

 fun add_eval_tyco (tyco, tyco') thy =

   let

     val k = Sign.arity_number thy tyco;

     fun pr pr' fxy [] = tyco'

       | pr pr' fxy [ty] =

           Code_Printer.concat [pr' Code_Printer.BR ty, tyco']

       | pr pr' fxy tys =

           Code_Printer.concat [Code_Printer.enum "," "(" ")" (map (pr' Code_Printer.BR) tys), tyco']

   in

     thy

     |> Code_Target.add_syntax_tyco target tyco (SOME (k, pr))

   end;

 fun add_eval_constr (const, const') thy =

   let

     val k = Code.args_number thy const;

     fun pr pr' fxy ts = Code_Printer.brackify fxy

       (const' :: the_list (Code_ML.print_tuple pr' Code_Printer.BR (map fst ts)));

   in

     thy

     |> Code_Target.add_syntax_const target const (SOME (Code_Printer.simple_const_syntax (k, pr)))

   end;

 fun add_eval_const (const, const') = Code_Target.add_syntax_const target

   const (SOME (Code_Printer.simple_const_syntax (0, (K o K o K) const')));

 fun process (code_body, (tyco_map, (constr_map, const_map))) module_name NONE thy =

       let

         val pr = Code_Printer.str o Long_Name.append module_name;

       in

         thy

         |> Code_Target.add_reserved target module_name

         |> Context.theory_map

           (ML_Context.exec (fn () => ML_Context.eval_text true Position.none code_body))

         |> fold (add_eval_tyco o apsnd pr) tyco_map

         |> fold (add_eval_constr o apsnd pr) constr_map

         |> fold (add_eval_const o apsnd pr) const_map

       end

   | process (code_body, _) _ (SOME file_name) thy =

       let

         val preamble = "(* Generated from " ^ Path.implode (ThyLoad.thy_path (Context.theory_name thy))

           ^ "; DO NOT EDIT! *)";

         val _ = File.write (Path.explode file_name) (preamble ^ "\n\n" ^ code_body);

       in

         thy

       end;

 fun gen_code_reflect prep_type prep_const raw_datatypes raw_functions module_name some_file thy  =

   let

     val datatypes = map (fn (raw_tyco, raw_cos) =>

       (prep_type thy raw_tyco, map (prep_const thy) raw_cos)) raw_datatypes;

     val _ = map (uncurry (check_datatype thy)) datatypes;

     val tycos = map fst datatypes;

     val constrs = maps snd datatypes;

     val functions = map (prep_const thy) raw_functions;

     val result = evaluation_code thy module_name tycos (constrs @ functions)

       |> (apsnd o apsnd) (chop (length constrs));

   in

     thy

     |> process result module_name some_file

   end;

 val code_reflect = gen_code_reflect Code_Target.cert_tyco Code.check_const;

 val code_reflect_cmd = gen_code_reflect Code_Target.read_tyco Code.read_const;

 (** Isar setup **)

 val _ = ML_Context.add_antiq "code" (fn _ => Args.term >> ml_code_antiq);

 local

 val datatypesK = "datatypes";

 val functionsK = "functions";

 val fileK = "file";

 val andK = "and"

 val _ = List.app Keyword.keyword [datatypesK, functionsK];

 val parse_datatype =

   Parse.name --| Parse.$$$ "=" -- (Parse.term ::: (Scan.repeat (Parse.$$$ "|" |-- Parse.term)));

 in

 val _ =

   Outer_Syntax.command "code_reflect" "enrich runtime environment with generated code"

     Keyword.thy_decl (Parse.name -- Scan.optional (Parse.$$$ datatypesK |-- (parse_datatype

       ::: Scan.repeat (Parse.$$$ andK |-- parse_datatype))) []

     -- Scan.optional (Parse.$$$ functionsK |-- Scan.repeat1 Parse.name) []

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

   >> (fn (((module_name, raw_datatypes), raw_functions), some_file) => Toplevel.theory

     (code_reflect_cmd raw_datatypes raw_functions module_name some_file)));

 end; (*local*)

 val setup = Code_Target.extend_target (target, (Code_ML.target_SML, K I));

 end; (*struct*)