(*  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"]

        | SYS_ERROR msg => ["## SYSTEM ERROR ##\n" ^ msg]

        | 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 =

  f

  |> debugging

  |> Future.interruptible_task;

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;