Schleifen steuern durch...

• Zähler

  for p in 1 .. 10 loop .. end loop;
  

• Daten

  map (\x -> x*x) [1,2,3] ==> [1,4,9]
  Collection<String> c 
      = new LinkedList<String> ();
  for (String s : c) { ... }
  

• Bedingung

  while ( x > 0 ) { if ( ... ) { x = ... } ... }
  

• Zustand (Iterator, hasNext, next)