diff -r 9321f7b70450 -r 6ee87f67d9cd src/Tools/intuitionistic.ML
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Tools/intuitionistic.ML	Sat Feb 28 14:52:21 2009 +0100
@@ -0,0 +1,100 @@
+(*  Title:      Tools/intuitionistic.ML
+    Author:     Stefan Berghofer, TU Muenchen
+
+Simple intuitionistic proof search.
+*)
+
+signature INTUITIONISTIC =
+sig
+  val prover_tac: Proof.context -> int option -> int -> tactic
+  val method_setup: bstring -> theory -> theory
+end;
+
+structure Intuitionistic: INTUITIONISTIC =
+struct
+
+(* main tactic *)
+
+local
+
+val remdups_tac = SUBGOAL (fn (g, i) =>
+  let val prems = Logic.strip_assums_hyp g in
+    REPEAT_DETERM_N (length prems - length (distinct op aconv prems))
+    (Tactic.ematch_tac [Drule.remdups_rl] i THEN Tactic.eq_assume_tac i)
+  end);
+
+fun REMDUPS tac = tac THEN_ALL_NEW remdups_tac;
+
+val bires_tac = Tactic.biresolution_from_nets_tac ContextRules.orderlist;
+
+fun safe_step_tac ctxt =
+  ContextRules.Swrap ctxt
+   (eq_assume_tac ORELSE'
+    bires_tac true (ContextRules.netpair_bang ctxt));
+
+fun unsafe_step_tac ctxt =
+  ContextRules.wrap ctxt
+   (assume_tac APPEND'
+    bires_tac false (ContextRules.netpair_bang ctxt) APPEND'
+    bires_tac false (ContextRules.netpair ctxt));
+
+fun step_tac ctxt i =
+  REPEAT_DETERM1 (REMDUPS (safe_step_tac ctxt) i) ORELSE
+  REMDUPS (unsafe_step_tac ctxt) i;
+
+fun intprover_tac ctxt gs d lim = SUBGOAL (fn (g, i) => if d > lim then no_tac else
+  let
+    val ps = Logic.strip_assums_hyp g;
+    val c = Logic.strip_assums_concl g;
+  in
+    if member (fn ((ps1, c1), (ps2, c2)) =>
+        c1 aconv c2 andalso
+        length ps1 = length ps2 andalso
+        gen_eq_set (op aconv) (ps1, ps2)) gs (ps, c) then no_tac
+    else (step_tac ctxt THEN_ALL_NEW intprover_tac ctxt ((ps, c) :: gs) (d + 1) lim) i
+  end);
+
+in
+
+fun prover_tac ctxt opt_lim =
+  SELECT_GOAL (DEEPEN (2, the_default 20 opt_lim) (intprover_tac ctxt [] 0) 4 1);
+
+end;
+
+
+(* method setup *)
+
+local
+
+val introN = "intro";
+val elimN = "elim";
+val destN = "dest";
+val ruleN = "rule";
+
+fun modifier name kind kind' att =
+  Args.$$$ name |-- (kind >> K NONE || kind' |-- OuterParse.nat --| Args.colon >> SOME)
+    >> (pair (I: Proof.context -> Proof.context) o att);
+
+val modifiers =
+ [modifier destN Args.bang_colon Args.bang ContextRules.dest_bang,
+  modifier destN Args.colon (Scan.succeed ()) ContextRules.dest,
+  modifier elimN Args.bang_colon Args.bang ContextRules.elim_bang,
+  modifier elimN Args.colon (Scan.succeed ()) ContextRules.elim,
+  modifier introN Args.bang_colon Args.bang ContextRules.intro_bang,
+  modifier introN Args.colon (Scan.succeed ()) ContextRules.intro,
+  Args.del -- Args.colon >> K (I, ContextRules.rule_del)];
+
+val method =
+  Method.bang_sectioned_args' modifiers (Scan.lift (Scan.option OuterParse.nat))
+    (fn n => fn prems => fn ctxt => Method.METHOD (fn facts =>
+      HEADGOAL (Method.insert_tac (prems @ facts) THEN'
+      ObjectLogic.atomize_prems_tac THEN' prover_tac ctxt n)));
+
+in
+
+fun method_setup name = Method.add_method (name, method, "intuitionistic proof search");
+
+end;
+
+end;
+