Overriding of RealType in vertical expressions

The original implementation o vector operations allowed to do this:

using VectorType = Containers::Vector< bool, Devices::Host >;
VectorType v( 100 );
v.setValue( true);
auto a = v.sum< int >();

The sumation would be performed in bool, by default, which would not give correct result. We can, however, simply change it to int. In the new implementation, we state

a = sum( v );

instead. I would like to be able to write a = sum< int >( v ) but I did not find any way how to do it.

Solution might be a = sum( ( int ) v ).