How can one make a variadic-based chained-indexing function?

Question

If I have an object a that either a built-in array or a class-type with a suitable operator [], and its returned type can be indexed itself, how should

Answer 1

To get the right return value for the slice function, you can create a helper template that computes the correct result type. For example:

template 
struct SliceResult {
    typedef typename SliceResult::Type Type;
};

template 
struct SliceResult {
    typedef typename std::underlying_type::type Type;
};

The slice function would then return a SliceResult<...>::Type.