chickadee » skiplists » skiplist-search!

command ((oldlevel newlevel (lambda (sls item)
                              (skiplist-search-level sls)))
         (oldfound newfound (lambda (sls item) (skiplist-found sls))))
requires (and (skiplist? sls)
              ((skiplist-item? sls) item))
ensures  (and (fx>= newlevel 0)
              (fx< newlevel (skiplist-height sls))
              ((list-of? (skiplist-item? sls)) newfound)
              ((list-of? zero?)
               (map (lambda (x) ((skiplist-compare sls) item x))
                    newfound)))