diff -r 44161f2c3226 -r 3020f8c76baa templates4/re.scala
--- a/templates4/re.scala	Wed Nov 28 17:13:40 2018 +0000
+++ b/templates4/re.scala	Wed Nov 28 23:26:47 2018 +0000
@@ -1,7 +1,7 @@
 // Part 1 about Regular Expression Matching
 //==========================================
 
-
+// Regular Expressions
 abstract class Rexp
 case object ZERO extends Rexp
 case object ONE extends Rexp
@@ -11,7 +11,7 @@
 case class STAR(r: Rexp) extends Rexp             // star
 
 
-// some convenience for typing in regular expressions
+// some convenience for typing regular expressions
 
 import scala.language.implicitConversions    
 import scala.language.reflectiveCalls 
@@ -102,11 +102,13 @@
 size(simp(der('a', der('a', EVIL))))           // => 8
 size(simp(der('a', der('a', der('a', EVIL))))) // => 8
 
-// Java needs around 30 seconds for matching 28 a's with EVIL. 
+// Python needs around 30 seconds for matching 28 a's with EVIL. 
+// Java 9 and later increase this to an "astonishing" 40000 a's in
+// 30 seconds.
 //
 // Lets see how long it really takes to match strings with 
-// 0.5 Million a's...it should be in the range of some
-// seconds.
+// 5 Million a's...it should be in the range of a couple
+// of seconds.
 
 def time_needed[T](i: Int, code: => T) = {
   val start = System.nanoTime()
@@ -119,5 +121,14 @@
   println(i + " " + "%.5f".format(time_needed(2, matcher(EVIL, "a" * i))))
 }
 
+// another "power" test case 
+simp(Iterator.iterate(ONE:Rexp)(r => SEQ(r, ONE | ONE)).drop(50).next) == ONE
+
+// the Iterator produces the rexp
+//
+//      SEQ(SEQ(SEQ(..., ONE | ONE) , ONE | ONE), ONE | ONE)
+//
+//    where SEQ is nested 50 times.
+
 */