Hi All

I have a suspicion this is all ancient history now, but I was surprised this code worked.

#include <iostream>

#include <vector>

#include <boost/range/adaptor/transformed.hpp>

struct TimesTwo

{

// using result_type = int;

int operator( )( int i ) const { return i * 2; }

};

int main( )

{

using namespace std;

using namespace boost::adaptors;

vector<int> v { 0, 1, 2, 3, 4, 5 };

for( int i : v | transformed( TimesTwo( ) ) ) { cout << i << " "; }

cout << endl;

}

Due to result_type being commented out. Am I right in thinking this is what BOOST_RESULT_OF_USE_DECLTYPE was all about, and everything now just works because modern compilers are implemtenting decltype now?

Kind Regards

Rob.