(Program
  (Call
    (Identifier)
  {+(Identifier)+}
    (Empty))
  (Call
    (Identifier)
  {-(Identifier)-}
    (Empty))
  (Call
    (Identifier)
  {-(Identifier)-}
    (Identifier)
  {+(Identifier)+}
    (Empty))
{-(Call
    (MemberAccess
      (Identifier)
      (Identifier))
    (Integer)
    (Empty))-})