(*  Title:      Pure/PIDE/command.ML

     Author:     Makarius

 Prover command execution.

 *)

 signature COMMAND =

 sig

   type span = Token.T list

   val range: span -> Position.range

   val proper_range: span -> Position.range

   type 'a memo

   val memo: (unit -> 'a) -> 'a memo

   val memo_value: 'a -> 'a memo

   val memo_eval: 'a memo -> 'a

   val memo_result: 'a memo -> 'a

   val eval: span -> Toplevel.transition ->

     Toplevel.state * {malformed: bool} -> {failed: bool} * (Toplevel.state * {malformed: bool})

   val no_print: unit lazy

   val print: Toplevel.transition -> Toplevel.state -> unit lazy

 end;

 structure Command: COMMAND =

 struct

 (* source *)

 type span = Token.T list;

 val range = Token.position_range_of;

 val proper_range = Token.position_range_of o #1 o take_suffix Token.is_improper;

 (* memo results *)

 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 ();  (*memoing of physical interrupts!*)

               in SOME (res, Result res) end))

   |> Exn.release;

 fun memo_result (Memo v) =

   (case Synchronized.value v of

     Result res => Exn.release res

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

 end;

 (* side-comments *)

 local

 fun cmts (t1 :: t2 :: toks) =

       if Token.keyword_with (fn s => s = "--") t1 then t2 :: cmts toks

       else cmts (t2 :: toks)

   | cmts _ = [];

 val span_cmts = filter Token.is_proper #> cmts;

 in

 fun check_cmts span tr st' =

   Toplevel.setmp_thread_position tr

     (fn () =>

       span_cmts span |> maps (fn cmt =>

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

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

 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 proof_status tr st =

   (case try Toplevel.proof_of st of

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

   | NONE => ());

 in

 fun eval span tr (st, {malformed}) =

   if malformed then

     ({failed = true}, (Toplevel.toplevel, {malformed = malformed}))

   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}, (st, {malformed = malformed'})) end

       | SOME st' =>

           let

             val _ = proof_status tr st';

           in ({failed = false}, (st', {malformed = malformed'})) end)

     end;

 end;

 (* print *)

 val no_print = Lazy.value ();

 fun print tr st' =

   let

     val is_init = Toplevel.is_init tr;

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

     val do_print =

       not is_init andalso

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

   in

     if do_print then

       (Lazy.lazy o Toplevel.setmp_thread_position tr)

         (fn () => Toplevel.print_state false st')

     else no_print

   end;

 end;