Merge branch 'changes-to-progfun1-week4' into 'master'

Fixes to progfun1-week4

See merge request lamp/cs-210-functional-programming-2019!9

slides/sources/progfun1-4-3.md

@@ -60,10 +60,10 @@ For instance, the `Student` type expands to something like:
   }
 ~~~
 
-Relationship With Case Classes(2)
-================================
+Comparison With Object Oriented Decomposition
+=============================================
 
-Case classes and algebraic data types are very similar.
+OO decomposition and algebraic data types are two ways of defining types and operations.
 
 When should you use one or the other?
 
@@ -72,7 +72,7 @@ Use an algebraic data type to model
  - a type with a fixed number of alternatives, where
  - all alternatives are pure data types that do not contain methods.
 
-Use a hierarchy with classes or case classes, if
+Use a hierarchy with classes, if
 
  - The set of alternatives is open, i.e. new alternatives can be added after the fact, or
  - Alternatives are complex, consisting of methods as well as parameters.

slides/sources/progfun1-4-4.md

@@ -79,7 +79,7 @@ Like classes, functions can have type parameters.
 
 For instance, here is a function that creates a list consisting of a single element.
 
-      def singleton[T](elem: T) = Cons[T](elem, Nil[T]())
+      def singleton[T](elem: T) = Node[T](elem, Empty[T]())
 
 We can then write:
 
@@ -139,4 +139,4 @@ Elements are numbered from 0.
 
 If index is outside the range from `0` up the the length of the list minus one, a `IndexOutOfBoundsException` should be thrown.
 
-\quiz
\ No newline at end of file
+\quiz

slides/sources/progfun1-4-5.md

@@ -120,10 +120,10 @@ To see why, consider the Java code below.
 
 \begin{lstlisting}
   NonEmpty[] a = new NonEmpty[]{
-    new NonEmpty(1, new Empty(), new Empty())}
-  IntSet[] b = a
-  b[0] = new Empty()
-  NonEmpty s = a[0]
+    new NonEmpty(1, new Empty(), new Empty())};
+  IntSet[] b = a;
+  b[0] = new Empty();
+  NonEmpty s = a[0];
 \end{lstlisting}
 
 It looks like we assigned in the last line an `Empty` set to a
@@ -172,4 +172,4 @@ When you try out this example, what do you observe?
 \\ \verb`  O         ` &       A program that compiles and runs without exception
 \end{tabular}
 ->
-\quiz
\ No newline at end of file
+\quiz