std::ranges::concat_view<Views...>::iterator<Const>::satisfy, prev, advance-fwd, advance-bwd
        concat_view::iterator::prev
concat_view::iterator::advance-fwd
concat_view::iterator::advance-bwd
The following exposition-only member function templates simplify the description.
Each helper function template has a constant template parameter of type std::size_t .
-  If the name of the template parameter is N, the template argument is always it_.index().
-  If the name of the template parameter is I, the template argument can be any std::size_t  value in [0,sizeof...(Views)).
However, the template argument might not be a compile-time constant, therefore the actual effect of helper <non_const>(/* arguments */) is similar to 
if (non_const == 0)
    helper <0>(/* arguments */);
else if (non_const == 1)
    helper <1>(/* arguments */);
/* other indices */
else if (non_const == (sizeof...(Views) - 1))
    helper <sizeof...(Views) - 1>(/* arguments */);
.
Contents
[edit] Helper templates
Mini helper templates
constexpr auto /*get-iter*/();
constexpr auto /*get-view*/();
constexpr auto /*get-begin*/();
constexpr auto /*get-end*/();
constexpr auto /*to-underlying-diff-type*/( difference_type value );
The mini helper templates simplify the description of the main helper templates and member functions. They are not included in the C++ standard documents.
it_  .concat_view.concat_view.get-view <I>()).concat_view.get-view <I>()). base-iter  >>>(value).
std::ranges::concat_view::iterator::satisfy<N>
constexpr void /*satisfy*/();
Adjusts the current (global) position of it_  .
std::ranges::concat_view::iterator::prev<N>
constexpr void /*prev*/();
Moves it_  to the previous (global) position.
std::ranges::concat_view::iterator::advance-fwd<N>
constexpr void /*advance-fwd*/( difference_type offset,
Advances the current (global) position step steps forward.
-  If N is sizeof...(Views) - 1, equivalent to get-iter<N>() +=to-underlying-diff-type(steps);.
-  Otherwise, equivalent to auto n_size = ranges::distance (get-view<N>()));
 if (offset + steps < n_size)get-iter<N>() +=to-underlying-diff-type(steps);
 else
 {it_.template emplace<N + 1>(get-begin<N + 1>());advance-fwd<N + 1>(0, offset + steps - n_size);
 }.
Parameters
it_  currently refers into
std::ranges::concat_view::iterator::advance-bwd<N>
constexpr void /*advance-bwd*/( difference_type offset,
Advances the current (global) position steps steps backward.
-  If N is 0, equivalent to get-iter<N>() -=to-underlying-diff-type(steps);.
-  Otherwise, equivalent to if (offset >= steps)get-iter<N>() -=to-underlying-diff-type(steps);
 else
 {get-view<N - 1>());it_.template emplace<N - 1>(get-end<N - 1>());advance-bwd<N - 1>(prev_size, steps - offset);
 }.
Parameters
it_  currently refers into