(Program
  (Call
    (Identifier)
  { (TextElement)
  ->(TextElement) }
  {-(Identifier)-}
    (Empty))
  (Call
    (Identifier)
    (TextElement)
  {+(Null)+}
  {-(Identifier)-}
  {-(Identifier)-}
    (Empty))
{+(Call
  {+(Identifier)+}
  {+(TextElement)+}
  {+(Identifier)+}
  {+(Identifier)+}
  {+(Empty)+})+}
{-(Call
  {-(Identifier)-}
  {-(TextElement)-}
  {-(Empty)-})-})