src/Pure/Thy/session.ML

tuned msg;

(*  Title:      Pure/Thy/session.ML
    ID:         $Id$
    Author:     Markus Wenzel, TU Muenchen

Session management -- maintain state of logic images.
*)

signature SESSION =
sig
  val path: unit -> string list
  val welcome: unit -> string
  val use_dir: bool -> bool -> string -> string -> unit
  val finish: unit -> unit
end;

structure Session: SESSION =
struct

(* session state *)

val pure = "Pure";

val session = ref ([pure]: string list);
val session_path = ref ([]: string list);
val session_finished = ref false;

fun path () = ! session_path;

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


(* diagnostics *)

fun str_of [id] = id
  | str_of ids = space_implode "/" (tl ids);

fun welcome () = "Welcome to Isabelle/" ^ str_of (! session) ^ " (" ^ version ^ ")";


(* init *)

fun init reset parent name =
  if not (parent mem_string (! session)) 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 () = (ThyInfo.finalize_all (); session_finished := true);


(* use_dir *)

val root_file = ThyLoad.ml_path "ROOT";

fun use_dir reset info parent name =
  (init reset parent name; Symbol.use root_file; finish ()) handle _ => exit 1;


end;