src/Pure/System/isar.ML

merged

(*  Title:      Pure/System/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
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 (ML_Compiler.exn_message exn)
        handle crash =>
          (CRITICAL (fn () => change crashes (cons crash));
            warning "Recovering from 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 ();
  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 ()};



(** command syntax **)

local

structure P = OuterParse and K = OuterKeyword;
val op >> = Scan.>>;

in

(* global history *)

val _ =
  OuterSyntax.improper_command "init_toplevel" "init toplevel point-of-interest" K.control
    (Scan.succeed (Toplevel.no_timing o Toplevel.imperative init));

val _ =
  OuterSyntax.improper_command "linear_undo" "undo commands" K.control
    (Scan.optional P.nat 1 >>
      (fn n => Toplevel.no_timing o Toplevel.imperative (fn () => linear_undo n)));

val _ =
  OuterSyntax.improper_command "undo" "undo commands (skipping closed proofs)" K.control
    (Scan.optional P.nat 1 >>
      (fn n => Toplevel.no_timing o Toplevel.imperative (fn () => undo n)));

val _ =
  OuterSyntax.improper_command "undos_proof" "undo commands (skipping closed proofs)" K.control
    (Scan.optional P.nat 1 >> (fn n => Toplevel.no_timing o
      Toplevel.keep (fn state =>
        if Toplevel.is_proof state then (undo n; print ()) else raise Toplevel.UNDEF)));

val _ =
  OuterSyntax.improper_command "cannot_undo" "partial undo -- Proof General legacy" K.control
    (P.name >>
      (fn "end" => Toplevel.no_timing o Toplevel.imperative (fn () => undo 1)
        | txt => Toplevel.imperative (fn () => error ("Cannot undo " ^ quote txt))));

val _ =
  OuterSyntax.improper_command "kill" "kill partial proof or theory development" K.control
    (Scan.succeed (Toplevel.no_timing o Toplevel.imperative kill));

end;

end;