I have inherited from boost::static_visitor<> and defined a class as follows:
class move_visitor : public boost::static_visitor<> {
private:
double m_dx, m_dy;
public:
move_visitor() : m_dx(0.0), m_dy(0.0) {}
move_visitor(double dx, double dy) : m_dx(dx), m_dy(dy) {}
~move_visitor() {}
void operator () (Point &p) const {
p.X(p.X() + m_dx);
p.Y(p.Y() + m_dy);
}
void operator () (Circle &c) const {
Point center_point(c.CentrePoint().X() + m_dx, c.CentrePoint().Y() + m_dy);
c.CentrePoint(center_point);
}
void operator() (Line &l) const {
Point start(l.Start().X() + m_dx, l.Start().Y() + m_dy),
end(l.End().X() + m_dx, l.End().Y() + m_dy);
l.Start(start);
l.End(end);
}
};
This class is supposed to change the x and y position of some objects, Point, Line and Circle.
When I execute the following code:
int main()
{
typedef boost::variant<Point, Line, Circle> ShapeType;
Point p(1, 2);
Line l(p, p);
Circle c(p, 5);
ShapeType shape_variant;
std::cout << p << "\n\n"
<< l << "\n\n"
<< c << "\n\n";
shape_variant = p;
boost::apply_visitor(move_visitor(2, 2), shape_variant);
std::cout << p << std::endl;
shape_variant = l;
boost::apply_visitor(move_visitor(2, 2), shape_variant);
std::cout << std::endl << l << std::endl;
return 0;
}
p remains as 1, 2 and so does l. Why aren't my object changing after 'apply_visitor`?
