(*  Title:      Pure/Isar/session.ML

    ID:         $Id$

    Author:     Markus Wenzel, TU Muenchen

Session management -- maintain state of logic images.

*)

signature SESSION =

sig

  val id: unit -> string list

  val name: unit -> string

  val welcome: unit -> string

  val use_dir: string -> bool -> string list -> bool -> bool -> string -> bool -> string list ->

    string -> string -> bool * string -> string -> int -> bool -> int -> int -> unit

  val finish: unit -> unit

end;

structure Session: SESSION =

struct

(* session state *)

val session = ref ([Context.PureN]: string list);

val session_path = ref ([]: string list);

val session_finished = ref false;

val remote_path = ref (NONE: Url.T option);

(* access path *)

fun id () = ! session;

fun path () = ! session_path;

fun str_of [] = Context.PureN

  | str_of elems = space_implode "/" elems;

fun name () = "Isabelle/" ^ str_of (path ());

val log = Path.explode "$ISABELLE_HOME/src/ChangeLog.gz";

fun welcome () =

  if Distribution.is_official then

    "Welcome to " ^ name () ^ " (" ^ Distribution.version ^ ")"

  else

    "Unofficial version of " ^ name () ^ " (" ^ Distribution.version ^ ")" ^

    (if File.exists log then "\nSee " ^ Path.implode (Path.expand log) ^ " for details" else "");

(* add_path *)

fun add_path reset s =

  let val sess = ! session @ [s] in

    (case duplicates (op =) sess of

      [] => (session := sess; session_path := ((if reset then [] else ! session_path) @ [s]))

    | dups => error ("Duplicate session identifiers " ^ commas_quote dups ^ " in " ^ str_of sess))

  end;

(* init *)

fun init reset parent name =

  if not (member (op =) (! session) parent) orelse not (! session_finished) then

    error ("Unfinished parent session " ^ quote parent ^ " for " ^ quote name)

  else (add_path reset name; session_finished := false);

(* finish *)

fun finish () =

  (Output.accumulated_time ();

    ThyInfo.finish ();

    Present.finish ();

    Toplevel.init_state ();

    session_finished := true);

(* use_dir *)

fun get_rpath rpath =

  (if rpath = "" then () else

     if is_some (! remote_path) then

       error "Path for remote theory browsing information may only be set once"

     else

       remote_path := SOME (Url.explode rpath);

   (! remote_path, rpath <> ""));

fun dumping (_, "") = NONE

  | dumping (cp, path) = SOME (cp, Path.explode path);

fun use_dir root build modes reset info doc doc_graph doc_versions

    parent name dump rpath level verbose max_threads trace_threads =

  ((fn () =>

     (init reset parent name;

      Present.init build info doc doc_graph doc_versions (path ()) name

        (dumping dump) (get_rpath rpath) verbose (map ThyInfo.theory (ThyInfo.names ()));

      use root;

      finish ()))

    |> setmp_noncritical Proofterm.proofs level

    |> setmp_noncritical print_mode (modes @ print_mode_value ())

    |> setmp_noncritical Multithreading.trace trace_threads

    |> setmp_noncritical Multithreading.max_threads

      (if Multithreading.available then max_threads

       else (if max_threads = 1 then () else warning "Multithreading support unavailable"; 1))) ()

  handle exn => (Output.error_msg (Toplevel.exn_message exn); exit 1);

end;