{

ServiceTimeTableEvent(ABVar abType)

: m_abType{ abType }

{}

inline ABVar const& GetABType() const { return m_abType; }

inline ABVar & GetABType() { return m_abType; }

ABVar m_abType;

: public boost::static_visitor<bool>

{

template<typename T, typename U>

bool operator()(T, U) const

{

return false; // cannot compare different types

}

template<typename T>

bool operator()(T lhs, T rhs) const

{

return lhs == rhs;

}

{

auto aTypePtr = IATypePtr{ new AType };

auto bTypePtr = IBTypePtr{ new BType };

ABVar aType = aTypePtr;

ABVar bType = bTypePtr;

ServiceTimeTableEvent timeTableEvent1{ aType };

ServiceTimeTableEvent timeTableEvent2{ bType };

auto xx = boost::apply_visitor(ab_are_equals(), timeTableEvent1.GetABType(), timeTableEvent2.GetABType());

xx = boost::apply_visitor(ab_are_equals(), timeTableEvent1.GetABType(), timeTableEvent1.GetABType());;

xx = boost::apply_visitor(ab_are_equals(), timeTableEvent2.GetABType(), timeTableEvent2.GetABType());;