(*  Title:      Pure/PIDE/command.ML

    Author:     Makarius

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

*)

signature COMMAND =

sig

  type eval_process

  type eval = {exec_id: Document_ID.exec, eval_process: eval_process}

  val eval_result_state: eval -> Toplevel.state

  type print_process

  type print = {name: string, pri: int, exec_id: Document_ID.exec, print_process: print_process}

  type exec = eval * print list

  val no_exec: exec

  val exec_ids: exec option -> Document_ID.exec list

  val stable_eval: eval -> bool

  val stable_print: print -> bool

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

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

  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} -> (string -> print_fn option) -> unit

  val no_print_function: string -> unit

  val execute: exec -> unit

end;

structure Command: COMMAND =

struct

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

datatype 'a expr =

  Expr of unit -> 'a |

  Result of 'a Exn.result;

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

with

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

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

fun memo_eval (Memo v) =

  (case Synchronized.value v of

    Result res => res

  | _ =>

      Synchronized.guarded_access v

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

          | Expr e =>

              let val res = Exn.capture e ();  (*sic!*)

              in SOME (res, Result res) end))

  |> Exn.release;

fun memo_fork params (Memo v) =

  (case Synchronized.value v of

    Result _ => ()

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

fun memo_result (Memo v) =

  (case Synchronized.value v of

    Result res => Exn.release res

  | _ => raise Fail "Unfinished memo result");

fun memo_stable (Memo v) =

  (case Synchronized.value v of

    Expr _ => true

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

end;

(** main phases of execution **)

(* basic type definitions *)

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};

type eval_process = eval_state memo;

type eval = {exec_id: Document_ID.exec, eval_process: eval_process};

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

val eval_result_state = #state o eval_result;

type print_process = unit memo;

type print = {name: string, pri: int, exec_id: Document_ID.exec, print_process: print_process};

type exec = eval * print list;

val no_exec: exec = ({exec_id = Document_ID.none, eval_process = memo_value init_eval_state}, []);

fun exec_ids (NONE: exec option) = []

  | exec_ids (SOME ({exec_id, ...}, prints)) = exec_id :: map #exec_id prints;

(* stable results *)

fun stable_goals exec_id =

  not (Par_Exn.is_interrupted (Future.join_results (Goal.peek_futures exec_id)));

fun stable_eval ({exec_id, eval_process}: eval) =

  stable_goals exec_id andalso memo_stable eval_process;

fun stable_print ({exec_id, print_process, ...}: print) =

  stable_goals exec_id andalso memo_stable print_process;

(* 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 *)

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

end;

(* print *)

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

local

type print_function = string * (int * (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);

in

fun print command_visible command_name eval old_prints =

  let

    fun new_print (name, (pri, get_print_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 {name = name, pri = pri, exec_id = exec_id, print_process = memo process} end;

      in

        (case Exn.capture (Runtime.controlled_execution get_print_fn) 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 (equal (fst pr) o #name) old_prints of

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

          | NONE => new_print pr))

      else filter stable_print old_prints;

  in

    if eq_list (op = o pairself #exec_id) (old_prints, new_prints) then NONE

    else SOME new_prints

  end;

fun print_function {name, pri} 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, 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} (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));

(* overall execution process *)

fun run_print ({name, pri, print_process, ...}: print) =

  (if Multithreading.enabled () then

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

  else memo_eval) print_process;

fun execute (({eval_process, ...}, prints): exec) =

  (memo_eval eval_process; List.app run_print prints);

end;