simplified handling of theory begin/end wrt. toplevel and theory loader;
(* Title: Pure/Isar/toplevel.ML
Author: Markus Wenzel, TU Muenchen
Isabelle/Isar toplevel transactions.
*)
signature TOPLEVEL =
sig
exception UNDEF
type state
val toplevel: state
val is_toplevel: state -> bool
val is_theory: state -> bool
val is_proof: state -> bool
val level: state -> int
val presentation_context_of: state -> Proof.context
val previous_context_of: state -> Proof.context option
val context_of: state -> Proof.context
val generic_theory_of: state -> generic_theory
val theory_of: state -> theory
val proof_of: state -> Proof.state
val proof_position_of: state -> int
val enter_proof_body: state -> Proof.state
val end_theory: Position.T -> state -> theory
val print_state_context: state -> unit
val print_state: bool -> state -> unit
val pretty_abstract: state -> Pretty.T
val quiet: bool Unsynchronized.ref
val debug: bool Unsynchronized.ref
val interact: bool Unsynchronized.ref
val timing: bool Unsynchronized.ref
val profiling: int Unsynchronized.ref
val skip_proofs: bool Unsynchronized.ref
exception TERMINATE
exception TOPLEVEL_ERROR
val program: (unit -> 'a) -> 'a
val thread: bool -> (unit -> unit) -> Thread.thread
type transition
val empty: transition
val init_of: transition -> string option
val name_of: transition -> string
val pos_of: transition -> Position.T
val str_of: transition -> string
val name: string -> transition -> transition
val position: Position.T -> transition -> transition
val interactive: bool -> transition -> transition
val print: transition -> transition
val no_timing: transition -> transition
val init_theory: string -> (bool -> theory) -> transition -> transition
val exit: transition -> transition
val keep: (state -> unit) -> transition -> transition
val keep': (bool -> state -> unit) -> transition -> transition
val imperative: (unit -> unit) -> transition -> transition
val ignored: Position.T -> transition
val malformed: Position.T -> string -> transition
val theory: (theory -> theory) -> transition -> transition
val generic_theory: (generic_theory -> generic_theory) -> transition -> transition
val theory': (bool -> theory -> theory) -> transition -> transition
val begin_local_theory: bool -> (theory -> local_theory) -> transition -> transition
val end_local_theory: transition -> transition
val local_theory': xstring option -> (bool -> local_theory -> local_theory) ->
transition -> transition
val local_theory: xstring option -> (local_theory -> local_theory) -> transition -> transition
val present_local_theory: xstring option -> (state -> unit) -> transition -> transition
val local_theory_to_proof': xstring option -> (bool -> local_theory -> Proof.state) ->
transition -> transition
val local_theory_to_proof: xstring option -> (local_theory -> Proof.state) ->
transition -> transition
val theory_to_proof: (theory -> Proof.state) -> transition -> transition
val end_proof: (bool -> Proof.state -> Proof.context) -> transition -> transition
val forget_proof: transition -> transition
val present_proof: (state -> unit) -> transition -> transition
val proofs': (bool -> Proof.state -> Proof.state Seq.seq) -> transition -> transition
val proof': (bool -> Proof.state -> Proof.state) -> transition -> transition
val proofs: (Proof.state -> Proof.state Seq.seq) -> transition -> transition
val proof: (Proof.state -> Proof.state) -> transition -> transition
val actual_proof: (Proof_Node.T -> Proof_Node.T) -> transition -> transition
val skip_proof: (int -> int) -> transition -> transition
val skip_proof_to_theory: (int -> bool) -> transition -> transition
val get_id: transition -> string option
val put_id: string -> transition -> transition
val unknown_theory: transition -> transition
val unknown_proof: transition -> transition
val unknown_context: transition -> transition
val setmp_thread_position: transition -> ('a -> 'b) -> 'a -> 'b
val status: transition -> Markup.T -> unit
val error_msg: transition -> exn * string -> unit
val add_hook: (transition -> state -> state -> unit) -> unit
val transition: bool -> transition -> state -> (state * (exn * string) option) option
val run_command: string -> transition -> state -> state option
val command: transition -> state -> state
val excursion: (transition * transition list) list -> (transition * state) list lazy * theory
end;
structure Toplevel: TOPLEVEL =
struct
(** toplevel state **)
exception UNDEF = Runtime.UNDEF;
(* local theory wrappers *)
val loc_init = Theory_Target.context_cmd;
val loc_exit = Local_Theory.exit_global;
fun loc_begin loc (Context.Theory thy) = loc_init (the_default "-" loc) thy
| loc_begin NONE (Context.Proof lthy) = lthy
| loc_begin (SOME loc) (Context.Proof lthy) = loc_init loc (loc_exit lthy);
fun loc_finish _ (Context.Theory _) = Context.Theory o loc_exit
| loc_finish NONE (Context.Proof _) = Context.Proof o Local_Theory.restore
| loc_finish (SOME _) (Context.Proof lthy) = fn lthy' =>
Context.Proof (Local_Theory.reinit (Local_Theory.raw_theory (K (loc_exit lthy')) lthy));
(* datatype node *)
datatype node =
Theory of generic_theory * Proof.context option
(*theory with presentation context*) |
Proof of Proof_Node.T * ((Proof.context -> generic_theory) * generic_theory)
(*proof node, finish, original theory*) |
SkipProof of int * (generic_theory * generic_theory);
(*proof depth, resulting theory, original theory*)
val theory_node = fn Theory (gthy, _) => SOME gthy | _ => NONE;
val proof_node = fn Proof (prf, _) => SOME prf | _ => NONE;
fun cases_node f _ (Theory (gthy, _)) = f gthy
| cases_node _ g (Proof (prf, _)) = g (Proof_Node.current prf)
| cases_node f _ (SkipProof (_, (gthy, _))) = f gthy;
val context_node = cases_node Context.proof_of Proof.context_of;
(* datatype state *)
datatype state = State of node option * node option; (*current, previous*)
val toplevel = State (NONE, NONE);
fun is_toplevel (State (NONE, _)) = true
| is_toplevel _ = false;
fun level (State (NONE, _)) = 0
| level (State (SOME (Theory _), _)) = 0
| level (State (SOME (Proof (prf, _)), _)) = Proof.level (Proof_Node.current prf)
| level (State (SOME (SkipProof (d, _)), _)) = d + 1; (*different notion of proof depth!*)
fun str_of_state (State (NONE, _)) = "at top level"
| str_of_state (State (SOME (Theory (Context.Theory _, _)), _)) = "in theory mode"
| str_of_state (State (SOME (Theory (Context.Proof _, _)), _)) = "in local theory mode"
| str_of_state (State (SOME (Proof _), _)) = "in proof mode"
| str_of_state (State (SOME (SkipProof _), _)) = "in skipped proof mode";
(* current node *)
fun node_of (State (NONE, _)) = raise UNDEF
| node_of (State (SOME node, _)) = node;
fun is_theory state = not (is_toplevel state) andalso is_some (theory_node (node_of state));
fun is_proof state = not (is_toplevel state) andalso is_some (proof_node (node_of state));
fun node_case f g state = cases_node f g (node_of state);
fun presentation_context_of state =
(case try node_of state of
SOME (Theory (_, SOME ctxt)) => ctxt
| SOME node => context_node node
| NONE => raise UNDEF);
fun previous_context_of (State (_, NONE)) = NONE
| previous_context_of (State (_, SOME prev)) = SOME (context_node prev);
val context_of = node_case Context.proof_of Proof.context_of;
val generic_theory_of = node_case I (Context.Proof o Proof.context_of);
val theory_of = node_case Context.theory_of Proof.theory_of;
val proof_of = node_case (fn _ => raise UNDEF) I;
fun proof_position_of state =
(case node_of state of
Proof (prf, _) => Proof_Node.position prf
| _ => raise UNDEF);
val enter_proof_body = node_case (Proof.init o Context.proof_of) Proof.enter_forward;
fun end_theory _ (State (NONE, SOME (Theory (Context.Theory thy, _)))) = Theory.end_theory thy
| end_theory pos _ = error ("Unfinished theory at end of input" ^ Position.str_of pos);
(* print state *)
val pretty_context = Local_Theory.pretty o Context.cases (Theory_Target.init NONE) I;
fun print_state_context state =
(case try node_of state of
NONE => []
| SOME (Theory (gthy, _)) => pretty_context gthy
| SOME (Proof (_, (_, gthy))) => pretty_context gthy
| SOME (SkipProof (_, (gthy, _))) => pretty_context gthy)
|> Pretty.chunks |> Pretty.writeln;
fun print_state prf_only state =
(case try node_of state of
NONE => []
| SOME (Theory (gthy, _)) => if prf_only then [] else pretty_context gthy
| SOME (Proof (prf, _)) =>
Proof.pretty_state (Proof_Node.position prf) (Proof_Node.current prf)
| SOME (SkipProof (d, _)) => [Pretty.str ("skipped proof: depth " ^ string_of_int d)])
|> Pretty.markup_chunks Markup.state |> Pretty.writeln;
fun pretty_abstract state = Pretty.str ("<Isar " ^ str_of_state state ^ ">");
(** toplevel transitions **)
val quiet = Unsynchronized.ref false;
val debug = Output.debugging;
val interact = Unsynchronized.ref false;
val timing = Output.timing;
val profiling = Unsynchronized.ref 0;
val skip_proofs = Unsynchronized.ref false;
exception TERMINATE = Runtime.TERMINATE;
exception EXCURSION_FAIL = Runtime.EXCURSION_FAIL;
exception TOPLEVEL_ERROR = Runtime.TOPLEVEL_ERROR;
fun program body =
(body
|> Runtime.controlled_execution
|> Runtime.toplevel_error (Output.error_msg o ML_Compiler.exn_message)) ();
fun thread interrupts body =
Thread.fork
(((fn () => body () handle Exn.Interrupt => ())
|> Runtime.debugging
|> Runtime.toplevel_error
(fn exn => priority ("## INTERNAL ERROR ##\n" ^ ML_Compiler.exn_message exn))),
Simple_Thread.attributes interrupts);
(* node transactions -- maintaining stable checkpoints *)
exception FAILURE of state * exn;
local
fun reset_presentation (Theory (gthy, _)) = Theory (gthy, NONE)
| reset_presentation node = node;
fun is_draft_theory (Theory (gthy, _)) = Context.is_draft (Context.theory_of gthy)
| is_draft_theory _ = false;
fun is_stale state = Context.is_stale (theory_of state) handle Runtime.UNDEF => false;
fun stale_error NONE = SOME (ERROR "Stale theory encountered after successful execution!")
| stale_error some = some;
fun map_theory f (Theory (gthy, ctxt)) =
Theory (Context.mapping f (Local_Theory.raw_theory f) gthy, ctxt)
| map_theory _ node = node;
in
fun apply_transaction f g node =
let
val _ = is_draft_theory node andalso error "Illegal draft theory in toplevel state";
val cont_node = reset_presentation node;
val back_node = map_theory (Theory.checkpoint o Theory.copy) cont_node;
fun state_error e nd = (State (SOME nd, SOME node), e);
val (result, err) =
cont_node
|> Runtime.controlled_execution f
|> map_theory Theory.checkpoint
|> state_error NONE
handle exn => state_error (SOME exn) cont_node;
val (result', err') =
if is_stale result then state_error (stale_error err) back_node
else (result, err);
in
(case err' of
NONE => tap g result'
| SOME exn => raise FAILURE (result', exn))
end;
end;
(* primitive transitions *)
datatype trans =
Init of string * (bool -> theory) | (*theory name, init*)
Exit | (*formal exit of theory*)
Keep of bool -> state -> unit | (*peek at state*)
Transaction of (bool -> node -> node) * (state -> unit); (*node transaction and presentation*)
local
fun apply_tr int (Init (_, f)) (State (NONE, _)) =
State (SOME (Theory (Context.Theory
(Theory.checkpoint (Runtime.controlled_execution f int)), NONE)), NONE)
| apply_tr _ Exit (State (prev as SOME (Theory (Context.Theory _, _)), _)) =
State (NONE, prev)
| apply_tr int (Keep f) state =
Runtime.controlled_execution (fn x => tap (f int) x) state
| apply_tr int (Transaction (f, g)) (State (SOME state, _)) =
apply_transaction (fn x => f int x) g state
| apply_tr _ _ _ = raise UNDEF;
fun apply_union _ [] state = raise FAILURE (state, UNDEF)
| apply_union int (tr :: trs) state =
apply_union int trs state
handle Runtime.UNDEF => apply_tr int tr state
| FAILURE (alt_state, UNDEF) => apply_tr int tr alt_state
| exn as FAILURE _ => raise exn
| exn => raise FAILURE (state, exn);
in
fun apply_trans int trs state = (apply_union int trs state, NONE)
handle FAILURE (alt_state, exn) => (alt_state, SOME exn) | exn => (state, SOME exn);
end;
(* datatype transition *)
datatype transition = Transition of
{name: string, (*command name*)
pos: Position.T, (*source position*)
int_only: bool, (*interactive-only*)
print: bool, (*print result state*)
no_timing: bool, (*suppress timing*)
trans: trans list}; (*primitive transitions (union)*)
fun make_transition (name, pos, int_only, print, no_timing, trans) =
Transition {name = name, pos = pos, int_only = int_only, print = print, no_timing = no_timing,
trans = trans};
fun map_transition f (Transition {name, pos, int_only, print, no_timing, trans}) =
make_transition (f (name, pos, int_only, print, no_timing, trans));
val empty = make_transition ("", Position.none, false, false, false, []);
(* diagnostics *)
fun init_of (Transition {trans = [Init (name, _)], ...}) = SOME name
| init_of _ = NONE;
fun name_of (Transition {name, ...}) = name;
fun pos_of (Transition {pos, ...}) = pos;
fun str_of tr = quote (name_of tr) ^ Position.str_of (pos_of tr);
fun command_msg msg tr = msg ^ "command " ^ str_of tr;
fun at_command tr = command_msg "At " tr ^ ".";
fun type_error tr state =
ERROR (command_msg "Illegal application of " tr ^ " " ^ str_of_state state);
(* modify transitions *)
fun name name = map_transition (fn (_, pos, int_only, print, no_timing, trans) =>
(name, pos, int_only, print, no_timing, trans));
fun position pos = map_transition (fn (name, _, int_only, print, no_timing, trans) =>
(name, pos, int_only, print, no_timing, trans));
fun interactive int_only = map_transition (fn (name, pos, _, print, no_timing, trans) =>
(name, pos, int_only, print, no_timing, trans));
val no_timing = map_transition (fn (name, pos, int_only, print, _, trans) =>
(name, pos, int_only, print, true, trans));
fun add_trans tr = map_transition (fn (name, pos, int_only, print, no_timing, trans) =>
(name, pos, int_only, print, no_timing, tr :: trans));
val reset_trans = map_transition (fn (name, pos, int_only, print, no_timing, _) =>
(name, pos, int_only, print, no_timing, []));
fun set_print print = map_transition (fn (name, pos, int_only, _, no_timing, trans) =>
(name, pos, int_only, print, no_timing, trans));
val print = set_print true;
(* basic transitions *)
fun init_theory name f = add_trans (Init (name, f));
val exit = add_trans Exit;
val keep' = add_trans o Keep;
fun present_transaction f g = add_trans (Transaction (f, g));
fun transaction f = present_transaction f (K ());
fun keep f = add_trans (Keep (fn _ => f));
fun imperative f = keep (fn _ => f ());
fun ignored pos = empty |> name "<ignored>" |> position pos |> imperative I;
fun malformed pos msg =
empty |> name "<malformed>" |> position pos |> imperative (fn () => error msg);
val unknown_theory = imperative (fn () => warning "Unknown theory context");
val unknown_proof = imperative (fn () => warning "Unknown proof context");
val unknown_context = imperative (fn () => warning "Unknown context");
(* theory transitions *)
fun generic_theory f = transaction (fn _ =>
(fn Theory (gthy, _) => Theory (f gthy, NONE)
| _ => raise UNDEF));
fun theory' f = transaction (fn int =>
(fn Theory (Context.Theory thy, _) =>
let val thy' = thy
|> Sign.new_group
|> Theory.checkpoint
|> f int
|> Sign.reset_group;
in Theory (Context.Theory thy', NONE) end
| _ => raise UNDEF));
fun theory f = theory' (K f);
fun begin_local_theory begin f = transaction (fn _ =>
(fn Theory (Context.Theory thy, _) =>
let
val lthy = f thy;
val gthy = if begin then Context.Proof lthy else Context.Theory (loc_exit lthy);
in Theory (gthy, SOME lthy) end
| _ => raise UNDEF));
val end_local_theory = transaction (fn _ =>
(fn Theory (Context.Proof lthy, _) => Theory (Context.Theory (loc_exit lthy), SOME lthy)
| _ => raise UNDEF));
local
fun local_theory_presentation loc f = present_transaction (fn int =>
(fn Theory (gthy, _) =>
let
val finish = loc_finish loc gthy;
val lthy' = loc_begin loc gthy
|> Local_Theory.new_group
|> f int
|> Local_Theory.reset_group;
in Theory (finish lthy', SOME lthy') end
| _ => raise UNDEF));
in
fun local_theory' loc f = local_theory_presentation loc f (K ());
fun local_theory loc f = local_theory' loc (K f);
fun present_local_theory loc = local_theory_presentation loc (K I);
end;
(* proof transitions *)
fun end_proof f = transaction (fn int =>
(fn Proof (prf, (finish, _)) =>
let val state = Proof_Node.current prf in
if can (Proof.assert_bottom true) state then
let
val ctxt' = f int state;
val gthy' = finish ctxt';
in Theory (gthy', SOME ctxt') end
else raise UNDEF
end
| SkipProof (0, (gthy, _)) => Theory (gthy, NONE)
| _ => raise UNDEF));
local
fun begin_proof init finish = transaction (fn int =>
(fn Theory (gthy, _) =>
let
val prf = init int gthy;
val skip = ! skip_proofs;
val schematic = Proof.schematic_goal prf;
in
if skip andalso schematic then
warning "Cannot skip proof of schematic goal statement"
else ();
if skip andalso not schematic then
SkipProof (0, (finish gthy (Proof.global_skip_proof int prf), gthy))
else Proof (Proof_Node.init prf, (finish gthy, gthy))
end
| _ => raise UNDEF));
in
fun local_theory_to_proof' loc f = begin_proof
(fn int => fn gthy => f int (Local_Theory.new_group (loc_begin loc gthy)))
(fn gthy => loc_finish loc gthy o Local_Theory.reset_group);
fun local_theory_to_proof loc f = local_theory_to_proof' loc (K f);
fun theory_to_proof f = begin_proof
(K (fn Context.Theory thy => f (Theory.checkpoint (Sign.new_group thy)) | _ => raise UNDEF))
(K (Context.Theory o Sign.reset_group o ProofContext.theory_of));
end;
val forget_proof = transaction (fn _ =>
(fn Proof (_, (_, orig_gthy)) => Theory (orig_gthy, NONE)
| SkipProof (_, (_, orig_gthy)) => Theory (orig_gthy, NONE)
| _ => raise UNDEF));
val present_proof = present_transaction (fn _ =>
(fn Proof (prf, x) => Proof (Proof_Node.apply I prf, x)
| skip as SkipProof _ => skip
| _ => raise UNDEF));
fun proofs' f = transaction (fn int =>
(fn Proof (prf, x) => Proof (Proof_Node.applys (f int) prf, x)
| skip as SkipProof _ => skip
| _ => raise UNDEF));
fun proof' f = proofs' (Seq.single oo f);
val proofs = proofs' o K;
val proof = proof' o K;
fun actual_proof f = transaction (fn _ =>
(fn Proof (prf, x) => Proof (f prf, x)
| _ => raise UNDEF));
fun skip_proof f = transaction (fn _ =>
(fn SkipProof (h, x) => SkipProof (f h, x)
| _ => raise UNDEF));
fun skip_proof_to_theory pred = transaction (fn _ =>
(fn SkipProof (d, (gthy, _)) => if pred d then Theory (gthy, NONE) else raise UNDEF
| _ => raise UNDEF));
(** toplevel transactions **)
(* identification *)
fun get_id (Transition {pos, ...}) = Position.get_id pos;
fun put_id id (tr as Transition {pos, ...}) = position (Position.put_id id pos) tr;
(* thread position *)
fun setmp_thread_position (Transition {pos, ...}) f x =
Position.setmp_thread_data pos f x;
fun status tr m =
setmp_thread_position tr (fn () => Output.status (Markup.markup m "")) ();
fun async_state (tr as Transition {print, ...}) st =
if print then
ignore
(Future.fork (fn () =>
setmp_thread_position tr (fn () => Future.report (fn () => print_state false st)) ()))
else ();
fun error_msg tr exn_info =
setmp_thread_position tr (fn () =>
Output.error_msg (ML_Compiler.exn_message (EXCURSION_FAIL exn_info))) ();
(* post-transition hooks *)
local
val hooks = Unsynchronized.ref ([]: (transition -> state -> state -> unit) list);
in
fun add_hook f = CRITICAL (fn () => Unsynchronized.change hooks (cons f));
fun get_hooks () = ! hooks;
end;
(* apply transitions *)
local
fun app int (tr as Transition {trans, print, no_timing, ...}) =
setmp_thread_position tr (fn state =>
let
fun do_timing f x = (warning (command_msg "" tr); timeap f x);
fun do_profiling f x = profile (! profiling) f x;
val (result, status) =
state |>
(apply_trans int trans
|> (! profiling > 0 andalso not no_timing) ? do_profiling
|> (! profiling > 0 orelse ! timing andalso not no_timing) ? do_timing);
val _ = if int andalso not (! quiet) andalso print then print_state false result else ();
in (result, Option.map (fn UNDEF => type_error tr state | exn => exn) status) end);
in
fun transition int tr st =
let
val hooks = get_hooks ();
fun apply_hooks st' = hooks |> List.app (fn f => (try (fn () => f tr st st') (); ()));
val ctxt = try context_of st;
val res =
(case app int tr st of
(_, SOME TERMINATE) => NONE
| (st', SOME (EXCURSION_FAIL exn_info)) => SOME (st', SOME exn_info)
| (st', SOME exn) => SOME (st', SOME (Runtime.exn_context ctxt exn, at_command tr))
| (st', NONE) => SOME (st', NONE));
val _ = (case res of SOME (st', NONE) => apply_hooks st' | _ => ());
in res end;
end;
(* managed execution *)
fun run_command thy_name tr st =
(case
(case init_of tr of
SOME name => Exn.capture (fn () => Thy_Header.consistent_name thy_name name) ()
| NONE => Exn.Result ()) of
Exn.Result () =>
let val int = is_some (init_of tr) in
(case transition int tr st of
SOME (st', NONE) =>
(status tr Markup.finished; if int then () else async_state tr st'; SOME st')
| SOME (_, SOME (exn as Exn.Interrupt, _)) => reraise exn
| SOME (_, SOME exn_info) => (error_msg tr exn_info; status tr Markup.failed; NONE)
| NONE => (error_msg tr (TERMINATE, at_command tr); status tr Markup.failed; NONE))
end
| Exn.Exn exn => (error_msg tr (exn, at_command tr); status tr Markup.failed; NONE));
(* nested commands *)
fun command tr st =
(case transition (! interact) tr st of
SOME (st', NONE) => st'
| SOME (_, SOME exn_info) => raise EXCURSION_FAIL exn_info
| NONE => raise EXCURSION_FAIL (TERMINATE, at_command tr));
fun command_result tr st =
let val st' = command tr st
in (st', st') end;
(* excursion of units, consisting of commands with proof *)
structure States = Proof_Data
(
type T = state list future option;
fun init _ = NONE;
);
fun proof_result immediate (tr, proof_trs) st =
let val st' = command tr st in
if immediate orelse
null proof_trs orelse
Keyword.is_schematic_goal (name_of tr) orelse
exists (Keyword.is_qed_global o name_of) proof_trs orelse
not (can proof_of st') orelse
Proof.is_relevant (proof_of st')
then
let val (states, st'') = fold_map command_result proof_trs st'
in (Lazy.value ((tr, st') :: (proof_trs ~~ states)), st'') end
else
let
val (body_trs, end_tr) = split_last proof_trs;
val finish = Context.Theory o ProofContext.theory_of;
val future_proof = Proof.global_future_proof
(fn prf =>
Future.fork_pri ~1 (fn () =>
let val (states, result_state) =
(case st' of State (SOME (Proof (_, (_, orig_gthy))), prev)
=> State (SOME (Proof (Proof_Node.init prf, (finish, orig_gthy))), prev))
|> fold_map command_result body_trs
||> command (end_tr |> set_print false);
in (states, presentation_context_of result_state) end))
#> (fn (states, ctxt) => States.put (SOME states) ctxt);
val st'' = st' |> command (end_tr |> reset_trans |> end_proof (K future_proof));
val states =
(case States.get (presentation_context_of st'') of
NONE => raise Fail ("No future states for " ^ name_of tr ^ Position.str_of (pos_of tr))
| SOME states => states);
val result = Lazy.lazy
(fn () => (tr, st') :: (body_trs ~~ Future.join states) @ [(end_tr, st'')]);
in (result, st'') end
end;
fun excursion input =
let
val end_pos = if null input then error "No input" else pos_of (fst (List.last input));
val immediate = not (Goal.future_enabled ());
val (results, end_state) = fold_map (proof_result immediate) input toplevel;
val thy = end_theory end_pos end_state;
in (Lazy.lazy (fn () => maps Lazy.force results), thy) end;
end;