It is for special usecase: some thing like a window function.
This commit relative to c9ae4fc886 .
Users who wants to access out-of-bounds of sequence, specify new
category to it.
struct sequence {
struct category
: fusion::random_access_traversal_tag
, fusion::no_bounds_tag {};
...
};
All of bounds related intrinsics of the /no-bounds-sequence/ *should*
guarantee to be well-defined or SFINAE-friendly, or compile error.
