Modifier 'for'

Method modifier 'for' enables us to declare and call "loop-like" methods.

  static for void eachEntry(int[] values, { int ==> void } block) {
    for (int p : values) {
      block.invoke(p);
    }
  }
  
  public static void main(String[] args) {
    int[] v = { 2, 3, 5, 7, 11 };
    for eachEntry(int i : v) {
      System.out.println(i);
      if (i > 3) {
        break;
      }
    }
  }
  

For example, we can declare a method that iterates through a map:

  static for <K, V> void eachMapEntry(Map<K, V> dict, 
      { K, V ==> void } block) {
    for (Map.Entry<K, V> entry : dict.entrySet()) {
      block.invoke(entry.getKey(), entry.getValue());
    }
  }
  
  public static void main(String[] args) {
    Map<String, String> dict = new HashMap<String, String>();
    ...
    for eachMapEntry(String k, String v : dict) {
      System.out.println(k + ": " + v);
    }
  }