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<b>Warning</b>:  session_start(): open(/var/lib/php/sessions/sess_a4jko4stk0qbr4iijlg78gmqgs, O_RDWR) failed: No space left on device (28) in <b>/var/www/tb-usercake/models/config.php</b> on line <b>51</b><br />
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<b>Warning</b>:  session_start(): Failed to read session data: files (path: /var/lib/php/sessions) in <b>/var/www/tb-usercake/models/config.php</b> on line <b>51</b><br />
sclass Chain<A> implements Iterable<A> {
  A element;
  Chain<A> next;
  int size;
  
  *() {}
  *(A *element) { size = 1; }
  *(A *element, Chain<A> *next) {
    size = next != null ? next.size+1 : 1;
  }
  
  toString { ret str(toList()); }
  
  ArrayList<A> toList() {
    ArrayList<A> l = emptyList(size);
    Chain<A> c = this;
    while (c != null) {
      l.add(c.element);
      c = c.next;
    }
    ret l;
  }
  
  // TODO: optimize
  public Iterator<A> iterator() { ret toList().iterator(); }
}