Added some examples that were shown to our handledare.

sample-programs/example-programs/ex5.crf

@@ -0,0 +1,26 @@
+main = case f (Just 10) of {
+    Just a => a ;
+    Nothing => 0 ;
+};
+ 
+f x = bind (fmap (\s . s + 1) x) (\s . pure (s + 10)) ;
+
+data Maybe () where {
+    Just : Int -> Maybe ()
+    Nothing : Maybe ()
+};
+
+fmap : (Int -> Int) -> Maybe () -> Maybe () ;
+fmap f m = case m of {
+    Just a => pure (f a) ;
+    Nothing => Nothing ;
+};
+
+pure : Int -> Maybe () ;
+pure x = Just x;
+
+bind : Maybe () -> (Int -> Maybe ()) -> Maybe () ;
+bind x f = case x of {
+    Just x => f x ;
+    Nothing => Nothing ;
+};