(*  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 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;

 (* exn_context *)

 exception CONTEXT of Proof.context * exn;

 fun exn_context NONE exn = exn

   | exn_context (SOME ctxt) exn = 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 = ! Output.debugging;

     fun exn_msgs _ (CONTEXT (ctxt, exn)) = exn_msgs (SOME ctxt) exn

       | exn_msgs ctxt (Exn.EXCEPTIONS exns) = maps (exn_msgs ctxt) exns

       | exn_msgs ctxt (EXCURSION_FAIL (exn, loc)) =

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

       | exn_msgs _ TERMINATE = ["Exit."]

       | exn_msgs _ Exn.Interrupt = []

       | exn_msgs _ TimeLimit.TimeOut = ["Timeout."]

       | exn_msgs _ TOPLEVEL_ERROR = ["Error."]

       | exn_msgs _ (SYS_ERROR msg) = ["## SYSTEM ERROR ##\n" ^ msg]

       | exn_msgs _ (ERROR msg) = [msg]

       | exn_msgs _ (exn as Fail msg) = [raised exn "Fail" [msg]]

       | exn_msgs _ (exn as THEORY (msg, thys)) =

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

       | exn_msgs _ (exn as Syntax.AST (msg, asts)) = [raised exn "AST" (msg ::

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

       | exn_msgs ctxt (exn as TYPE (msg, Ts, ts)) = [raised exn "TYPE" (msg ::

             (if detailed then

               if_context ctxt Syntax.string_of_typ Ts @ if_context ctxt Syntax.string_of_term ts

              else []))]

       | exn_msgs ctxt (exn as TERM (msg, ts)) = [raised exn "TERM" (msg ::

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

       | exn_msgs ctxt (exn as THM (msg, i, thms)) = [raised exn ("THM " ^ string_of_int i) (msg ::

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

       | exn_msgs _ exn = [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 ! Output.debugging 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 =

   f

   |> debugging

   |> Future.interruptible_task;

 fun toplevel_error output_exn f x =

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

   in f x handle exn => (output_exn (exn_context ctxt exn); raise TOPLEVEL_ERROR) end;

 end;