sclass CIString implements Comparable<CIString>, CharSequence {
  char[] data; // could be final except for persistence
  
  *() {}
  *(char[] s) { data = String.valueOf(assertNotNull(s)); }
  *(S s) { data = toCharArray(s); }
  
  // note that eq(s, cistring) is still false
  public bool equals(Object o) {
    if (o cast CIString)
      ret eqicCharArrays(data, o.data);
    /*if (o instanceof String) // One-way interoperability!
      return s.equalsIgnoreCase((String) o);*/
    false;
  }
  
  public int compareTo(CIString cis) {
    ret compareCharArraysIC(data, cis.data);
  }
  
  toString { ret str(data); }
  
  public char charAt(int index) { ret data[index]; }
  public int length() { ret data.length; }
  public CharSequence subSequence(int start, int end) {
    ret CIString(subCharArray(data, start, end));
  }
}

Began life as a copy of #1002873