--- a/progs/re3.scala	Tue Oct 10 18:53:30 2017 +0100
+++ b/progs/re3.scala	Wed Oct 11 13:48:53 2017 +0100
@@ -1,6 +1,7 @@
 // Version with simplification during derivatives;
 // this keeps the regular expressions small, which
 // is good for run-time
+ 
 
 abstract class Rexp
 case object ZERO extends Rexp