diff -r 937c995b047a -r ff815ca0bbcf progs/lecture1.scala
--- a/progs/lecture1.scala	Wed Jul 04 14:48:05 2018 +0100
+++ b/progs/lecture1.scala	Tue Jul 10 15:09:28 2018 +0100
@@ -51,7 +51,7 @@
 
 // some alterative syntax for lists
 
-1::2::3::Nil
+1 :: 2 :: 3 :: Nil
 List(1, 2, 3) ::: List(4, 5, 6)
 
 // Printing/Strings
@@ -126,13 +126,13 @@
 val lyrics = "Sun dips down, the day has gone. \n" +
              "Witches, wolves and giants yawn. \n" +
              "Queen and dragon, troll and gnome: \n" +
-             "tired buddies head for home"
+             "tired buddies head for home."
 */ 
 
 val lyrics = """Sun dips down, the day has gone.
                 |Witches, wolves and giants yawn.
                 |Queen and dragon, troll and gnome:
-                |tired buddies head for home""".stripMargin
+                |tired buddies head for home.""".stripMargin
 
 println(lyrics)
 
@@ -171,6 +171,9 @@
 // If-Conditionals
 //=================
 
+// Scala does not have a then-keyword
+// both if-else branches need to be presents
+
 def fact(n: Int) : Int = 
   if (n == 0) 1 else n * fact(n - 1)
 
@@ -186,13 +189,13 @@
 */
 
 
-def fact2(n: BigInt): BigInt = 
+def fact2(n: BigInt) : BigInt = 
   if (n == 0) 1 else n * fact2(n - 1)
 
 fact2(150)
 
 
-def fib(n: Int): Int =
+def fib(n: Int) : Int =
   if (n == 0) 1 else
     if (n == 1) 1 else fib(n - 1) + fib(n - 2)
 
@@ -252,6 +255,9 @@
 
 mult_table.sliding(10,10).mkString("\n")
 
+// the list can also be constructed in any other way
+for (n <- List(10,12,4,5,7,8,10)) yield n * n
+
 
 // with if-predicates
 
@@ -270,6 +276,14 @@
 for (p <- List((1, 4), (2, 3), (3, 2), (4, 1))) yield p._1 + p._2 
 
 
+// general pattern
+
+for (x <- ...) yield {
+  // potentially complicated
+  // calculation of a result
+}
+
+
 
 // with only a side-effect (no list is produced),
 // has no "yield"
@@ -278,9 +292,6 @@
 
 
 
-
-
-
 // concurrency (ONLY WORKS IN SCALA 2.11.8, not in SCALA 2.12)
 //             (would need to have this wrapped into a function, or
 //              REPL called with scala -Yrepl-class-based)
@@ -303,7 +314,7 @@
 
 
 // mutable vs immutable factorial
-def fact_mu(n: Long): Long = {
+def fact_mu(n: Long) : Long = {
   var result : Long = 1
   var i = 1
   while (i <= n) {
@@ -326,8 +337,8 @@
   }
 }
 
-test().sum
-println(l1.sum - l2.sum)
+(for (i <- (1 to 10)) yield test().sum).sum
+
 
 // Webpages
 //==========
@@ -533,7 +544,7 @@
 santa_state("(((((()))))".toList)
 santa_imutable("(((((()))))".toList)
 
-def randomString(length: Int) = 
+def randomString(length: Int) : String = 
   List.fill(length)((40 + scala.util.Random.nextInt(2)).toChar)