 or an applied occurrence with no
    corresponding defining occurrence.<p>

      All of the occurrences of <em>Identifier</em> in the productions
      for <em>Program</em>, <em>ParameterDecl</em>,
      <em>ConstantDecl</em> and <em>VariableDecl</em> are defining
      occurrences, except the last occurrence in <em>Program</em>.
      All instances of <em>Identifier</em> in other productions are
      applied occurrences.<p>

      The last occurrence of <em>Identifier</em> in the
      <em>Program</em> 