(*  Title:      Pure/Isar/runtime.ML

     Author:     Makarius

 Isar toplevel runtime support.

 *)

 signature RUNTIME =

 sig

   exception UNDEF

   exception TERMINATE

   exception EXCURSION_FAIL of exn * string

   exception TOPLEVEL_ERROR

   val debug: bool Unsynchronized.ref

   val exn_context: Proof.context option -> exn -> exn

   val exn_messages: (exn -> Position.T) -> exn -> string list

   val exn_message: (exn -> Position.T) -> exn -> string

   val debugging: ('a -> 'b) -> 'a -> 'b

   val controlled_execution: ('a -> 'b) -> 'a -> 'b

   val toplevel_error: (exn -> unit) -> ('a -> 'b) -> 'a -> 'b

 end;

 structure Runtime: RUNTIME =

 struct

 (** exceptions **)

 exception UNDEF;

 exception TERMINATE;

 exception EXCURSION_FAIL of exn * string;

 exception TOPLEVEL_ERROR;

 val debug = Unsynchronized.ref false;

 (* exn_context *)

 exception CONTEXT of Proof.context * exn;

 fun exn_context NONE exn = exn

   | exn_context (SOME ctxt) exn = if Exn.is_interrupt exn then exn else CONTEXT (ctxt, exn);

 (* exn_message *)

 fun if_context NONE _ _ = []

   | if_context (SOME ctxt) f xs = map (f ctxt) xs;

 fun exn_messages exn_position e =

   let

     fun raised exn name msgs =

       let val pos = Position.str_of (exn_position exn) in

         (case msgs of

           [] => "exception " ^ name ^ " raised" ^ pos

         | [msg] => "exception " ^ name ^ " raised" ^ pos ^ ": " ^ msg

         | _ => cat_lines (("exception " ^ name ^ " raised" ^ pos ^ ":") :: msgs))

       end;

     val detailed = ! debug;

     fun exn_msgs context exn =

       if Exn.is_interrupt exn then []

       else

         (case exn of

           Exn.EXCEPTIONS exns => maps (exn_msgs context) exns

         | CONTEXT (ctxt, exn) => exn_msgs (SOME ctxt) exn

         | EXCURSION_FAIL (exn, loc) =>

             map (fn msg => msg ^ Markup.markup Markup.no_report ("\n" ^ loc)) (exn_msgs context exn)

         | TERMINATE => ["Exit"]

         | TimeLimit.TimeOut => ["Timeout"]

         | TOPLEVEL_ERROR => ["Error"]

         | ERROR msg => [msg]

         | Fail msg => [raised exn "Fail" [msg]]

         | THEORY (msg, thys) =>

             [raised exn "THEORY" (msg :: (if detailed then map Context.str_of_thy thys else []))]

         | Syntax.AST (msg, asts) =>

             [raised exn "AST" (msg ::

               (if detailed then map (Pretty.string_of o Syntax.pretty_ast) asts else []))]

         | TYPE (msg, Ts, ts) =>

             [raised exn "TYPE" (msg ::

               (if detailed then

                 if_context context Syntax.string_of_typ Ts @

                 if_context context Syntax.string_of_term ts

                else []))]

         | TERM (msg, ts) =>

             [raised exn "TERM" (msg ::

               (if detailed then if_context context Syntax.string_of_term ts else []))]

         | THM (msg, i, thms) =>

             [raised exn ("THM " ^ string_of_int i) (msg ::

               (if detailed then if_context context Display.string_of_thm thms else []))]

         | _ => [raised exn (General.exnMessage exn) []]);

   in exn_msgs NONE e end;

 fun exn_message exn_position exn =

   (case exn_messages exn_position exn of

     [] => "Interrupt"

   | msgs => cat_lines msgs);

 (** controlled execution **)

 fun debugging f x =

   if ! debug then

     Exn.release (exception_trace (fn () =>

       Exn.Result (f x) handle

         exn as UNDEF => Exn.Exn exn

       | exn as EXCURSION_FAIL _ => Exn.Exn exn))

   else f x;

 fun controlled_execution f x =

   ((f |> debugging |> Future.interruptible_task) x before Multithreading.interrupted ());

 fun toplevel_error output_exn f x = f x

   handle exn =>

     if Exn.is_interrupt exn then reraise exn

     else

       let

         val ctxt = Option.map Context.proof_of (Context.thread_data ());

         val _ = output_exn (exn_context ctxt exn);

       in raise TOPLEVEL_ERROR end;

 end;