Module Make_no_zero.Array

type index = t
type 'a t
val empty : 'a t
val singleton : 'a -> 'a t
val extend : 'a t -> index -> (index -> 'a) -> 'a t
val retract : 'a t -> index -> 'a t
val contains : 'a t -> index -> bool
val last : 'a t -> index option
val set : 'a t -> index -> 'a -> unit
val get : 'a t -> index -> 'a