--- a/progs/token.scala	Sat May 05 10:31:00 2018 +0100
+++ b/progs/token.scala	Fri Jun 01 15:28:37 2018 +0100
@@ -105,6 +105,15 @@
   case c::s => ders(s, der(c, r))
 }
 
+val test : Rexp= STAR("a" | "aa")
+size(test)
+size(der('a', test))
+size(der('a', der('a', test)))
+
+size(ders("aaaaaa".toList, test)) 
+string(ders("aaaaaa".toList, test))
+
+
 // extracts a string from value
 def flatten(v: Val) : String = v match {
   case Empty => ""