Interaction between runtime and fusion sequences

Further to my question C++ Tuple of Boost.Range - get Tuple of element types?

I have the following:

TupleOfRanges ranges; 
TupleOfElements elements;

std::vector<int> offsets;

All containers (both meta and runtime) are of size N. I would like to write code that does the following:

boost::fusion::at_c<0>(elements) 
    = *(boost::begin(boost::fusion::at_c<0>(ranges)) + offset[0]);
boost::fusion::at_c<1>(elements) 
    = *(boost::begin(boost::fusion::at_c<1>(ranges)) + offset[1]);
// ...
boost::fusion::at_c<N>(elements) 
    = *(boost::begin(boost::fusion::at_c<N>(ranges)) + offset[N]);

I have tried writing this using Fusion's trans开发者_如何学Pythonform operation but the problem would seem to be that the functor does not know the index of the element it is operating on.

I thought that something like:

elements 
    = boost::fusion::transform(boost::fusion::zip(ranges, indices), getValue);

might work if I could somehow make Fusion sequence indices containing int 0...N

So can someone help me make an ascending sequence, or find a better way to achieve my goal? Many thanks.

You can obtain a sequence of ascending non-type template parameters with boost::mpl::range_c. You will need to copy this sequence to another mpl::sequence as ranges don't fulfil all necessary concept requirements to be used with transform. The sequence can be adapted with fusion.