(*  Title:      Pure/Isar/isar.ML

    Author:     Makarius

The global Isabelle/Isar state and main read-eval-print loop.

*)

signature ISAR =

sig

  val init: unit -> unit

  val exn: unit -> (exn * string) option

  val state: unit -> Toplevel.state

  val context: unit -> Proof.context

  val goal: unit -> thm

  val print: unit -> unit

  val >> : Toplevel.transition -> bool

  val >>> : Toplevel.transition list -> unit

  val linear_undo: int -> unit

  val undo: int -> unit

  val kill: unit -> unit

  val kill_proof: unit -> unit

  val crashes: exn list ref

  val toplevel_loop: {init: bool, welcome: bool, sync: bool, secure: bool} -> unit

  val loop: unit -> unit

  val main: unit -> unit

  type id = string

  val no_id: id

  val create_command: Toplevel.transition -> id

  val insert_command: id -> id -> unit

  val remove_command: id -> unit

end;

structure Isar: ISAR =

struct

(** TTY model -- SINGLE-THREADED! **)

(* the global state *)

type history = (Toplevel.state * Toplevel.transition) list;

  (*previous state, state transition -- regular commands only*)

local

  val global_history = ref ([]: history);

  val global_state = ref Toplevel.toplevel;

  val global_exn = ref (NONE: (exn * string) option);

in

fun edit_history count f = NAMED_CRITICAL "Isar" (fn () =>

  let

    fun edit 0 (st, hist) = (global_history := hist; global_state := st; global_exn := NONE)

      | edit n (st, hist) = edit (n - 1) (f st hist);

  in edit count (! global_state, ! global_history) end);

fun state () = NAMED_CRITICAL "Isar" (fn () => ! global_state);

fun set_state state = NAMED_CRITICAL "Isar" (fn () => global_state := state);

fun exn () = NAMED_CRITICAL "Isar" (fn () => ! global_exn);

fun set_exn exn =  NAMED_CRITICAL "Isar" (fn () => global_exn := exn);

end;

fun init () = edit_history 1 (K (K (Toplevel.toplevel, [])));

fun context () = Toplevel.context_of (state ())

  handle Toplevel.UNDEF => error "Unknown context";

fun goal () = #2 (#2 (Proof.get_goal (Toplevel.proof_of (state ()))))

  handle Toplevel.UNDEF => error "No goal present";

fun print () = Toplevel.print_state false (state ());

(* history navigation *)

local

fun find_and_undo _ [] = error "Undo history exhausted"

  | find_and_undo which ((prev, tr) :: hist) =

      ((case Toplevel.init_of tr of SOME name => ThyInfo.kill_thy name | NONE => ());

        if which (Toplevel.name_of tr) then (prev, hist) else find_and_undo which hist);

in

fun linear_undo n = edit_history n (K (find_and_undo (K true)));

fun undo n = edit_history n (fn st => fn hist =>

  find_and_undo (if Toplevel.is_proof st then K true else OuterKeyword.is_theory) hist);

fun kill () = edit_history 1 (fn st => fn hist =>

  find_and_undo

    (if Toplevel.is_proof st then OuterKeyword.is_theory else OuterKeyword.is_theory_begin) hist);

fun kill_proof () = edit_history 1 (fn st => fn hist =>

  if Toplevel.is_proof st then find_and_undo OuterKeyword.is_theory hist

  else raise Toplevel.UNDEF);

end;

(* interactive state transformations *)

fun op >> tr =

  (case Toplevel.transition true tr (state ()) of

    NONE => false

  | SOME (_, SOME err) => (set_exn (SOME err); Toplevel.error_msg tr err; true)

  | SOME (st', NONE) =>

      let

        val name = Toplevel.name_of tr;

        val _ = if OuterKeyword.is_theory_begin name then init () else ();

        val _ =

          if OuterKeyword.is_regular name

          then edit_history 1 (fn st => fn hist => (st', (st, tr) :: hist)) else ();

      in true end);

fun op >>> [] = ()

  | op >>> (tr :: trs) = if op >> tr then op >>> trs else ();

(* toplevel loop *)

val crashes = ref ([]: exn list);

local

fun raw_loop secure src =

  let

    fun check_secure () =

      (if secure then warning "Secure loop -- cannot exit to ML" else (); secure);

  in

    (case Source.get_single (Source.set_prompt Source.default_prompt src) of

      NONE => if secure then quit () else ()

    | SOME (tr, src') => if op >> tr orelse check_secure () then raw_loop secure src' else ())

    handle exn => (Output.error_msg (Toplevel.exn_message exn)

    handle crash =>

      (CRITICAL (fn () => change crashes (cons crash));

        warning "Recovering after Isar toplevel crash -- see also Isar.crashes");

      raw_loop secure src)

  end;

in

fun toplevel_loop {init = do_init, welcome, sync, secure} =

 (Context.set_thread_data NONE;

  if do_init then init () else ();  (* FIXME init editor model *)

  if welcome then writeln (Session.welcome ()) else ();

  uninterruptible (fn _ => fn () => raw_loop secure (OuterSyntax.isar sync)) ());

end;

fun loop () =

  toplevel_loop {init = false, welcome = false, sync = false, secure = Secure.is_secure ()};

fun main () =

  toplevel_loop {init = true, welcome = true, sync = false, secure = Secure.is_secure ()};

(** individual toplevel commands **)

(* unique identification *)

type id = string;

val no_id : id = "";

(* command category *)

datatype category = Empty | Theory | Proof | Diag | Control;

fun category_of tr =

  let val name = Toplevel.name_of tr in

    if name = "" then Empty

    else if OuterKeyword.is_theory name then Theory

    else if OuterKeyword.is_proof name then Proof

    else if OuterKeyword.is_diag name then Diag

    else Control

  end;

val is_theory = fn Theory => true | _ => false;

val is_proper = fn Theory => true | Proof => true | _ => false;

val is_regular = fn Control => false | _ => true;

(* command status *)

datatype status =

  Unprocessed |

  Running |

  Failed of exn * string |

  Finished of Toplevel.state;

fun status_markup Unprocessed = Markup.unprocessed

  | status_markup Running = Markup.running

  | status_markup (Failed _) = Markup.failed

  | status_markup (Finished _) = Markup.finished;

fun run int tr state =

  (case Toplevel.transition int tr state of

    NONE => NONE

  | SOME (_, SOME err) => (Toplevel.error_msg tr err; SOME (Failed err))

  | SOME (state', NONE) => SOME (Finished state'));

(* datatype command *)

datatype command = Command of

 {category: category,

  transition: Toplevel.transition,

  status: status};

fun make_command (category, transition, status) =

  Command {category = category, transition = transition, status = status};

val empty_command =

  make_command (Empty, Toplevel.empty, Finished Toplevel.toplevel);

fun map_command f (Command {category, transition, status}) =

  make_command (f (category, transition, status));

fun map_status f = map_command (fn (category, transition, status) =>

  (category, transition, f status));

(* global collection of identified commands *)

fun err_dup id = sys_error ("Duplicate command " ^ quote id);

fun err_undef id = sys_error ("Unknown command " ^ quote id);

local val global_commands = ref (Graph.empty: command Graph.T) in

fun change_commands f = NAMED_CRITICAL "Isar" (fn () => change global_commands f)

  handle Graph.DUP bad => err_dup bad | Graph.UNDEF bad => err_undef bad;

fun get_commands () = NAMED_CRITICAL "Isar" (fn () => ! global_commands);

end;

fun add_edge (id1, id2) =

  if id1 = no_id orelse id2 = no_id then I else Graph.add_edge (id1, id2);

fun init_commands () = change_commands (K Graph.empty);

fun the_command id =

  let val Command cmd =

    if id = no_id then empty_command

    else (Graph.get_node (get_commands ()) id handle Graph.UNDEF bad => err_undef bad)

  in cmd end;

fun prev_command id =

  if id = no_id then no_id

  else

    (case Graph.imm_preds (get_commands ()) id handle Graph.UNDEF bad => err_undef bad of

      [] => no_id

    | [prev] => prev

    | _ => sys_error ("Non-linear command dependency " ^ quote id));

fun next_commands id =

  if id = no_id then []

  else Graph.imm_succs (get_commands ()) id handle Graph.UNDEF bad => err_undef bad;

fun descendant_commands ids =

  Graph.all_succs (get_commands ()) (distinct (op =) (filter_out (fn id => id = no_id) ids))

    handle Graph.UNDEF bad => err_undef bad;

(* maintain status *)

fun report_status markup id = Toplevel.status (#transition (the_command id)) markup;

fun update_status status id = change_commands (Graph.map_node id (map_status (K status)));

fun report_update_status status id =

  change_commands (Graph.map_node id (map_status (fn old_status =>

    let val markup = status_markup status

    in if markup <> status_markup old_status then report_status markup id else (); status end)));

(* create and dispose commands *)

fun create_command raw_tr =

  let

    val (id, tr) =

      (case Toplevel.get_id raw_tr of

        SOME id => (id, raw_tr)

      | NONE =>

          let val id =

            if ! Toplevel.debug then "isabelle:" ^ Toplevel.name_of raw_tr ^ serial_string ()

            else "isabelle:" ^ serial_string ()

          in (id, Toplevel.put_id id raw_tr) end);

    val cmd = make_command (category_of tr, tr, Unprocessed);

    val _ = change_commands (Graph.new_node (id, cmd));

  in id end;

fun dispose_commands ids =

  let

    val desc = descendant_commands ids;

    val _ = List.app (report_status Markup.disposed) desc;

    val _ = change_commands (Graph.del_nodes desc);

  in () end;

(* final state *)

fun the_state id =

  (case the_command id of

    {status = Finished state, ...} => state

  | {transition, ...} => error ("Unfinished command " ^ Toplevel.str_of transition));

(** editor model **)

(* run commands *)

fun try_run id =

  (case try the_state (prev_command id) of

    NONE => ()

  | SOME state =>

      (case run true (#transition (the_command id)) state of

        NONE => ()

      | SOME status => report_update_status status id));

fun rerun_commands ids =

  (List.app (report_update_status Unprocessed) ids; List.app try_run ids);

(* modify document *)

fun insert_command prev id = NAMED_CRITICAL "Isar" (fn () =>

  let

    val nexts = next_commands prev;

    val _ = change_commands

     (fold (fn next => Graph.del_edge (prev, next)) nexts #> add_edge (prev, id) #>

      fold (fn next => Graph.add_edge (id, next)) nexts);

  in descendant_commands [id] end) |> rerun_commands;

fun remove_command id = NAMED_CRITICAL "Isar" (fn () =>

  let

    val prev = prev_command id;

    val nexts = next_commands id;

    val _ = change_commands

     (fold (fn next => Graph.del_edge (id, next)) nexts #>

      fold (fn next => add_edge (prev, next)) nexts);

  in descendant_commands nexts end) |> rerun_commands;

(* concrete syntax *)

local

structure P = OuterParse;

val op >> = Scan.>>;

in

val _ =

  OuterSyntax.internal_command "Isar.command"

    (P.string -- P.string >> (fn (id, text) =>

      Toplevel.imperative (fn () =>

        ignore (create_command (OuterSyntax.prepare_command (Position.id id) text)))));

val _ =

  OuterSyntax.internal_command "Isar.insert"

    (P.string -- P.string >> (fn (prev, id) =>

      Toplevel.imperative (fn () => insert_command prev id)));

val _ =

  OuterSyntax.internal_command "Isar.remove"

    (P.string >> (fn id => Toplevel.imperative (fn () => remove_command id)));

end;

end;