(*  Title:      Pure/PIDE/command.ML

     Author:     Makarius

 Prover command execution: read -- eval -- print.

 *)

 signature COMMAND =

 sig

   val read: (unit -> theory) -> Token.T list -> Toplevel.transition

   type eval

   val eval_eq: eval * eval -> bool

   val eval_result_state: eval -> Toplevel.state

   val eval_stable: eval -> bool

   val eval: (unit -> theory) -> Token.T list -> eval -> eval

   type print

   val print: bool -> string -> eval -> print list -> print list option

   type print_fn = Toplevel.transition -> Toplevel.state -> unit

   val print_function: {name: string, pri: int, persistent: bool} ->

     ({command_name: string} -> print_fn option) -> unit

   val no_print_function: string -> unit

   type exec = eval * print list

   val no_exec: exec

   val exec_ids: exec option -> Document_ID.exec list

   val exec: Document_ID.execution -> exec -> unit

 end;

 structure Command: COMMAND =

 struct

 (** memo results -- including physical interrupts! **)

 datatype 'a expr =

   Expr of Document_ID.exec * (unit -> 'a) |

   Result of 'a Exn.result;

 abstype 'a memo = Memo of 'a expr Synchronized.var

 with

 fun memo exec_id e = Memo (Synchronized.var "Command.memo" (Expr (exec_id, e)));

 fun memo_value a = Memo (Synchronized.var "Command.memo" (Result (Exn.Res a)));

 fun memo_result (Memo v) =

   (case Synchronized.value v of

     Expr (exec_id, _) => error ("Unfinished execution result: " ^ Document_ID.print exec_id)

   | Result res => Exn.release res);

 fun memo_stable (Memo v) =

   (case Synchronized.value v of

    Expr _ => true

  | Result res => not (Exn.is_interrupt_exn res));

 fun memo_exec execution_id (Memo v) =

   (case Synchronized.value v of

     Result res => res

   | Expr _ =>

       Synchronized.timed_access v (fn _ => SOME Time.zeroTime)

         (fn Result res => SOME (res, Result res)

           | expr as Expr (exec_id, e) =>

               uninterruptible (fn restore_attributes => fn () =>

                 if Execution.running execution_id exec_id then

                   let

                     val res = Exn.capture (restore_attributes e) ();

                     val _ = Execution.finished exec_id;

                   in SOME (res, Result res) end

                 else SOME (Exn.interrupt_exn, expr)) ())

       |> (fn NONE => error "Concurrent execution attempt" | SOME res => res))

   |> Exn.release |> ignore;

 fun memo_fork params execution_id (Memo v) =

   (case Synchronized.value v of

     Result _ => ()

   | _ => ignore ((singleton o Future.forks) params (fn () => memo_exec execution_id (Memo v))));

 end;

 (** main phases of execution **)

 (* read *)

 fun read init span =

   let

     val outer_syntax = #2 (Outer_Syntax.get_syntax ());

     val command_reports = Outer_Syntax.command_reports outer_syntax;

     val proper_range =

       Position.set_range (Token.position_range_of (#1 (take_suffix Token.is_improper span)));

     val pos =

       (case find_first Token.is_command span of

         SOME tok => Token.position_of tok

       | NONE => proper_range);

     val (is_malformed, token_reports) = Thy_Syntax.reports_of_tokens span;

     val _ = Position.reports_text (token_reports @ maps command_reports span);

   in

     if is_malformed then Toplevel.malformed pos "Malformed command syntax"

     else

       (case Outer_Syntax.read_spans outer_syntax span of

         [tr] =>

           if Keyword.is_control (Toplevel.name_of tr) then

             Toplevel.malformed pos "Illegal control command"

           else Toplevel.modify_init init tr

       | [] => Toplevel.ignored (Position.set_range (Token.position_range_of span))

       | _ => Toplevel.malformed proper_range "Exactly one command expected")

       handle ERROR msg => Toplevel.malformed proper_range msg

   end;

 (* eval *)

 type eval_state =

   {failed: bool, malformed: bool, command: Toplevel.transition, state: Toplevel.state};

 val init_eval_state =

   {failed = false, malformed = false, command = Toplevel.empty, state = Toplevel.toplevel};

 datatype eval = Eval of {exec_id: Document_ID.exec, eval_process: eval_state memo};

 fun eval_eq (Eval {exec_id, ...}, Eval {exec_id = exec_id', ...}) = exec_id = exec_id';

 fun eval_result (Eval {eval_process, ...}) = memo_result eval_process;

 val eval_result_state = #state o eval_result;

 fun eval_stable (Eval {exec_id, eval_process}) =

   Goal.stable_futures exec_id andalso memo_stable eval_process;

 local

 fun run int tr st =

   if Goal.future_enabled () andalso Keyword.is_diag (Toplevel.name_of tr) then

     (Goal.fork_params {name = "Toplevel.diag", pos = Toplevel.pos_of tr, pri = ~1}

       (fn () => Toplevel.command_exception int tr st); ([], SOME st))

   else Toplevel.command_errors int tr st;

 fun check_cmts span tr st' =

   Toplevel.setmp_thread_position tr

     (fn () =>

       Outer_Syntax.side_comments span |> maps (fn cmt =>

         (Thy_Output.check_text (Token.source_position_of cmt) st'; [])

           handle exn => ML_Compiler.exn_messages_ids exn)) ();

 fun proof_status tr st =

   (case try Toplevel.proof_of st of

     SOME prf => Toplevel.status tr (Proof.status_markup prf)

   | NONE => ());

 fun eval_state span tr ({malformed, state = st, ...}: eval_state) =

   if malformed then

     {failed = true, malformed = malformed, command = tr, state = Toplevel.toplevel}

   else

     let

       val malformed' = Toplevel.is_malformed tr;

       val is_init = Toplevel.is_init tr;

       val is_proof = Keyword.is_proof (Toplevel.name_of tr);

       val _ = Multithreading.interrupted ();

       val _ = Toplevel.status tr Markup.running;

       val (errs1, result) = run (is_init orelse is_proof) (Toplevel.set_print false tr) st;

       val errs2 = (case result of NONE => [] | SOME st' => check_cmts span tr st');

       val errs = errs1 @ errs2;

       val _ = Toplevel.status tr Markup.finished;

       val _ = List.app (Future.error_msg (Toplevel.pos_of tr)) errs;

     in

       (case result of

         NONE =>

           let

             val _ = if null errs then Exn.interrupt () else ();

             val _ = Toplevel.status tr Markup.failed;

           in {failed = true, malformed = malformed', command = tr, state = st} end

       | SOME st' =>

           let

             val _ = proof_status tr st';

           in {failed = false, malformed = malformed', command = tr, state = st'} end)

     end;

 in

 fun eval init span eval0 =

   let

     val exec_id = Document_ID.make ();

     fun process () =

       let

         val tr =

           Position.setmp_thread_data (Position.id_only (Document_ID.print exec_id))

             (fn () => read init span |> Toplevel.exec_id exec_id) ();

       in eval_state span tr (eval_result eval0) end;

   in Eval {exec_id = exec_id, eval_process = memo exec_id process} end;

 end;

 (* print *)

 datatype print = Print of

  {name: string, pri: int, persistent: bool,

   exec_id: Document_ID.exec, print_process: unit memo};

 type print_fn = Toplevel.transition -> Toplevel.state -> unit;

 local

 type print_function = string * (int * bool * ({command_name: string} -> print_fn option));

 val print_functions = Synchronized.var "Command.print_functions" ([]: print_function list);

 fun print_error tr e =

   (Toplevel.setmp_thread_position tr o Runtime.controlled_execution) e () handle exn =>

     List.app (Future.error_msg (Toplevel.pos_of tr)) (ML_Compiler.exn_messages_ids exn);

 fun print_eq (Print {exec_id, ...}, Print {exec_id = exec_id', ...}) = exec_id = exec_id';

 fun print_stable (Print {exec_id, print_process, ...}) =

   Goal.stable_futures exec_id andalso memo_stable print_process;

 fun print_persistent (Print {persistent, ...}) = persistent;

 in

 fun print command_visible command_name eval old_prints =

   let

     fun new_print (name, (pri, persistent, get_fn)) =

       let

         fun make_print strict print_fn =

           let

             val exec_id = Document_ID.make ();

             fun process () =

               let

                 val {failed, command, state = st', ...} = eval_result eval;

                 val tr = Toplevel.exec_id exec_id command;

               in

                 if failed andalso not strict then ()

                 else print_error tr (fn () => print_fn tr st')

               end;

           in

            Print {

              name = name, pri = pri, persistent = persistent,

              exec_id = exec_id, print_process = memo exec_id process}

           end;

       in

         (case Exn.capture (Runtime.controlled_execution get_fn) {command_name = command_name} of

           Exn.Res NONE => NONE

         | Exn.Res (SOME print_fn) => SOME (make_print false print_fn)

         | Exn.Exn exn => SOME (make_print true (fn _ => fn _ => reraise exn)))

       end;

     val new_prints =

       if command_visible then

         rev (Synchronized.value print_functions) |> map_filter (fn pr =>

           (case find_first (fn Print {name, ...} => name = fst pr) old_prints of

             SOME print => if print_stable print then SOME print else new_print pr

           | NONE => new_print pr))

       else filter (fn print => print_persistent print andalso print_stable print) old_prints;

   in

     if eq_list print_eq (old_prints, new_prints) then NONE else SOME new_prints

   end;

 fun print_function {name, pri, persistent} f =

   Synchronized.change print_functions (fn funs =>

    (if not (AList.defined (op =) funs name) then ()

     else warning ("Redefining command print function: " ^ quote name);

     AList.update (op =) (name, (pri, persistent, f)) funs));

 fun no_print_function name =

   Synchronized.change print_functions (filter_out (equal name o #1));

 end;

 val _ =

   print_function {name = "print_state", pri = 0, persistent = true}

     (fn {command_name} => SOME (fn tr => fn st' =>

       let

         val is_init = Keyword.is_theory_begin command_name;

         val is_proof = Keyword.is_proof command_name;

         val do_print =

           not is_init andalso

             (Toplevel.print_of tr orelse (is_proof andalso Toplevel.is_proof st'));

       in if do_print then Toplevel.print_state false st' else () end));

 (* combined execution *)

 type exec = eval * print list;

 val no_exec: exec =

   (Eval {exec_id = Document_ID.none, eval_process = memo_value init_eval_state}, []);

 fun exec_ids NONE = []

   | exec_ids (SOME (Eval {exec_id, ...}, prints)) =

       exec_id :: map (fn Print {exec_id, ...} => exec_id) prints;

 local

 fun run_print execution_id (Print {name, pri, print_process, ...}) =

   (if Multithreading.enabled () then

     memo_fork {name = name, group = NONE, deps = [], pri = pri, interrupts = true}

   else memo_exec) execution_id print_process;

 in

 fun exec execution_id (Eval {eval_process, ...}, prints) =

   (memo_exec execution_id eval_process; List.app (run_print execution_id) prints);

 end;

 end;