// the problem with this is the lack of a contract-compliant hashCode()
sclass CIString implements Comparable<CIString>, CharSequence {
  S s; // final
  
  *() {}
  *(S *s) { assertNotNull(s); }
  
  // note that eq(s, cistring) is still false
  public boolean equals(Object o) {
    if (o instanceof CIString)
      return s.equalsIgnoreCase(((CIString) o).s);
    if (o instanceof String) // One-way interoperability!
      return s.equalsIgnoreCase((String) o);
    return false;
  }
  
  public int compareTo(CIString cis) {
    ret s.compareToIgnoreCase(cis.s);
  }
  
  public S toString() {
    ret s;
  }
  
  public S str() {
    ret s;
  }
  
  public char charAt(int index) { ret s.charAt(index); }
  public int length() { ret s.length(); }
  public CharSequence subSequence(int start, int end) {
    ret CIString(s.substring(start, end));
  }
}