H_PREV
rv = history(hist, &ev, H_PREV))
#define HIST_PREV(el) HIST_FUN(el, H_PREV, NULL)
case H_PREV:
while (ev.num != curr_num && history(h, &ev, H_PREV) == 0)
he = _move_history(H_PREV);
if (history(h, &ev, direction < 0 ? H_NEXT:H_PREV) != 0)
if (history(h, &ev, (pos < 0) ? H_PREV : H_NEXT) != 0)