(Program
  (Call
    (Identifier)
  {-(Identifier)-}
    (Identifier)
    (Empty))
{+(Context
    (Comment)
    (Call
      (Identifier)
      (Identifier)
      (Identifier)
      (Empty)))+}
{-(Call
    (Identifier)
    (Identifier)
    (Empty))-}
{-(Context
    (Comment)
    (Empty))-})