"Steven Allmaras" wrote
I would like to do a compile-time mapping of an array accessor to a list
of
scalars as in the following class:
class MyArray1 {
public:
double& operator[](int n) { ??? }
private:
double a0, a1, a2, a3 ;
} ;
int main() {
MyArray1 x ;
x[1] = 2. ;
}
How about something like this:
#include
#include
#include
#include <iostream>
using namespace std;
#define DEFINE_FUNC(z, n, _)\
double& operator[](boost::mpl::int_<n>)\
{\
return a ## n;\
}
#define DEFINE_ARRAY(Name, n)\
class Name\
{\
public:\
BOOST_PP_REPEAT(n, DEFINE_FUNC, ~)\
private:\
double BOOST_PP_ENUM_PARAMS(4, a);\
};
DEFINE_ARRAY(MyArray1, 4)
int main()
{
MyArray1 x;
x[boost::mpl::int_<0>()] = 2.;
x[boost::mpl::int_<3>()] = 5.;
// x[boost::mpl::int_<4>()] = 7.; // compile error
cout << x[boost::mpl::int_<0>()] << endl;
cout << x[boost::mpl::int_<3>()] << endl;
}
Regards,
Arkadiy
