obsolete (cf. proof_node.ML);

--- a/src/Pure/Isar/proof_history.ML	Mon Jul 14 11:19:36 2008 +0200
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,76 +0,0 @@
-(*  Title:      Pure/Isar/proof_history.ML
-    ID:         $Id$
-    Author:     Markus Wenzel, TU Muenchen
-
-Histories of proof states, with undo / redo and backtracking.
-*)
-
-signature PROOF_HISTORY =
-sig
-  type T
-  val position: T -> int
-  val init: int option -> Proof.state -> T
-  val is_initial: T -> bool
-  val map_current: (Proof.state -> Proof.state) -> T -> T
-  val current: T -> Proof.state
-  val previous: T -> Proof.state option
-  val clear: int -> T -> T
-  val undo: T -> T
-  val redo: T -> T
-  val back: T -> T
-  val applys: (Proof.state -> Proof.state Seq.seq) -> T -> T
-  val apply: (Proof.state -> Proof.state) -> T -> T
-end;
-
-structure ProofHistory: PROOF_HISTORY =
-struct
-
-
-(* datatype proof history *)
-
-type node =
-  Proof.state *                 (*first result*)
-  Proof.state Seq.seq;          (*alternative results*)
-
-type proof = node * int;        (*proof node, proof position*)
-
-datatype T = ProofHistory of proof History.T;
-
-fun app f (ProofHistory x) = ProofHistory (f x);
-fun hist_app f = app (History.apply f);
-fun hist_map f = app (History.map_current f);
-
-fun position (ProofHistory prf) = snd (History.current prf);
-
-
-(* generic history operations *)
-
-fun init lim st = ProofHistory (History.init lim ((st, Seq.empty), 0));
-fun is_initial (ProofHistory prf) = History.is_initial prf;
-fun map_current f = hist_map (apfst (apfst f));
-fun current (ProofHistory prf) = fst (fst (History.current prf));
-fun previous (ProofHistory prf) = Option.map (fst o fst) (History.previous prf);
-val clear = app o History.clear;
-val undo = app History.undo;
-val redo = app History.redo;
-
-
-(* backtracking *)
-
-val back = hist_app (fn ((_, stq), position) =>
-  (case Seq.pull stq of
-    NONE => error "back: no alternatives"
-  | SOME result => (result, position)));
-
-
-(* apply transformer *)
-
-fun applys f = hist_app (fn (node as (st, _), position) =>
-  (case Seq.pull (f st) of
-    NONE => error "empty result sequence -- proof command failed"
-  | SOME results => (results, position + 1)));
-
-fun apply f = applys (Seq.single o f);
-
-
-end;