diff -r bfa28e1cba77 -r 788b27dfaefa src/HOL/Tools/ATP/atp_util.ML
--- a/src/HOL/Tools/ATP/atp_util.ML	Mon May 20 12:35:29 2013 +0200
+++ b/src/HOL/Tools/ATP/atp_util.ML	Mon May 20 13:07:31 2013 +0200
@@ -14,6 +14,7 @@
   val strip_spaces : bool -> (char -> bool) -> string -> string
   val strip_spaces_except_between_idents : string -> string
   val elide_string : int -> string -> string
+  val find_enclosed : string -> string -> string -> string list
   val nat_subscript : int -> string
   val unquote_tvar : string -> string
   val unyxml : string -> string
@@ -121,6 +122,14 @@
   else
     s
 
+fun find_enclosed left right s =
+  case first_field left s of
+    SOME (_, s) =>
+    (case first_field right s of
+       SOME (enclosed, s) => enclosed :: find_enclosed left right s
+     | NONE => [])
+  | NONE => []
+
 val subscript = implode o map (prefix "\<^isub>") o raw_explode  (* FIXME Symbol.explode (?) *)
 fun nat_subscript n =
   n |> string_of_int |> print_mode_active Symbol.xsymbolsN ? subscript