else if ( name_str == "current_nightfall" )
  {
    struct current_nightfall_expr_t: public expr_t
    {
      warlock_t& player;
      current_nightfall_expr_t( warlock_t& p ):
        expr_t( "current_nightfall" ), player( p ) { }
      virtual double evaluate() { return player.double_nightfall; }
    };
    return new current_nightfall_expr_t( *this );
  }