--- a/progs/comb1.scala	Mon Oct 24 14:46:47 2016 +0100
+++ b/progs/comb1.scala	Sat Oct 29 21:45:44 2016 +0100
@@ -156,3 +156,41 @@
 (One ~ One ~ One ~ One).parse("1111")
 
 (One || Two).parse("111")
+
+
+for (x <- List(1, 2, 3, 4)) println(x)
+for (x <- List(1, 2, 3, 4); if (2 < x)) yield (x.toString + x.toString)
+for (x <- List("2", "1", "3", "4", "1")) yield (x + x + x)
+
+(1, "one", '1')._3
+for ((x, y) <- List((1, "one"), (2, "two"), (3, "three"), (4,"many")); if (y == "many"))
+  yield (x.toString + y)
+
+
+def square(n: Int) = {
+  n * n
+}
+
+square(4 + 3 + 5)
+
+def bar(): Int = {
+  bar()
+  3
+}
+
+
+def foo(n: => Int) = {
+  print("finished")
+}
+
+foo(bar())
+
+square(12) + square(10)
+
+
+def time_needed[T](i: Int, code: => T) = {
+  val start = System.nanoTime()
+  for (j <- 1 to i) code
+  val end = System.nanoTime()
+  (end - start)/(i * 1.0e9)
+}

--- a/progs/re1.scala	Mon Oct 24 14:46:47 2016 +0100
+++ b/progs/re1.scala	Sat Oct 29 21:45:44 2016 +0100
@@ -62,9 +62,9 @@
 val EVIL2 = SEQ(STAR(STAR(CHAR('a'))), CHAR('b'))
 
 //for measuring time
-def time_needed[T](i: Int, code: => T) = {
+def time_needed[T](i: Int, code => T) = {
   val start = System.nanoTime()
-  for (j <- 1 to i) code
+  for (j <- 1 to i) code()
   val end = System.nanoTime()
   (end - start)/(i * 1.0e9)
 }

--- a/progs/re3.scala	Mon Oct 24 14:46:47 2016 +0100
+++ b/progs/re3.scala	Sat Oct 29 21:45:44 2016 +0100
@@ -8,6 +8,7 @@
 case class STAR(r: Rexp) extends Rexp 
 case class NTIMES(r: Rexp, n: Int) extends Rexp 
 
+
 // nullable function: tests whether the regular 
 // expression can recognise the empty string
 def nullable (r: Rexp) : Boolean = r match {
@@ -47,7 +48,6 @@
     case (r1s, ONE) => r1s
     case (r1s, r2s) => SEQ(r1s, r2s)
   }
-  case NTIMES(r1, n) => NTIMES(simp(r1), n)
   case r => r
 }
 

--- a/progs/re4.scala	Mon Oct 24 14:46:47 2016 +0100
+++ b/progs/re4.scala	Sat Oct 29 21:45:44 2016 +0100
@@ -57,7 +57,7 @@
   case (s, ONE) => if (s == Nil) ONE else ZERO
   case (s, CHAR(c)) => if (s == List(c)) ONE else 
                        if (s == Nil) CHAR(c) else ZERO
-  case (s, ALT(r1, r2)) => ALT(ders2(s, r2), ders2(s, r2))
+  case (s, ALT(r1, r2)) => ALT(ders2(s, r1), ders2(s, r2))
   case (c::s, r) => ders2(s, simp(der(c, r)))
 }