src/Pure/General/exn.scala

     else if (exn.isInstanceOf[RuntimeException]) Some(exn.toString)
     else None
 
   def message(exn: Throwable): String =
     user_message(exn) getOrElse exn.toString
+
+
+  /* recover from spurious crash */
+
+  def recover[A](e: => A): A =
+  {
+    capture(e) match {
+      case Res(x) => x
+      case Exn(exn) =>
+        capture(e) match {
+          case Res(x) =>
+            java.lang.System.err.println("Recovered from spurious crash after retry!")
+            exn.printStackTrace()
+            x
+          case Exn(_) => throw exn
+        }
+    }
+  }
 }