chickadee » random-access-lists » ral-split

function (head tail)
requires (and (ral? ls) (fixnum? place)
              (fx>= place 0) (fx< place (ral-count ls)))
ensures  (and (ral? head) (ral? tail)
              (fx= (ral-count head) place)
              (fx= (ral-count tail) (fx- (ral-count ls) place)))