#include <type_traits>
#include <iostream>
template<typename TDerived> class
t_ImplicitlyConvertableToAnything
{
public: template
<
typename TTarget
, typename TEnabled = typename ::std::enable_if_t<::std::is_integral<TTarget>::value>
>
operator TTarget(void) const
{
auto const & self{static_cast<const TDerived &>(*this)};
return(self.template CheckedConversion_To_Integral<TTarget>());
}
};
template<typename TDerived> class
t_ExplicitlyConvertableToAnything
{
public: template
<
typename TTarget
, typename TEnabled = typename ::std::enable_if_t<!::std::is_integral<TTarget>::value>
> explicit
operator TTarget(void) const
{
auto const & self{static_cast<const TDerived &>(*this)};
return(self.template CheckedConversion_To_NonIntegral<TTarget>());
}
};
class
t_ConvertableToAnything
: public t_ImplicitlyConvertableToAnything<t_ConvertableToAnything>
, public t_ExplicitlyConvertableToAnything<t_ConvertableToAnything>
{
public: template<typename TTarget> decltype(auto)
CheckedConversion_To_Integral(void) const
{
return(static_cast<TTarget>(1));
}
public: template<typename TTarget> decltype(auto)
CheckedConversion_To_NonIntegral(void) const
{
return(static_cast<TTarget>(3.14));
}
};
int main()
{
t_ConvertableToAnything c;
::std::cout << ([](int x){return(x);})(c) << ::std::endl;
::std::cout << static_cast<float>(c) << ::std::endl;
return(0);
}