sliceable

public struct Slice<Base : Indexable> : CollectionType {
    public typealias Index = Base.Index
    public let startIndex: Base.Index
    public let endIndex: Base.Index
    public subscript (index: Base.Index) -> Base._Element { get }
    public subscript (bounds: Range<Base.Index>) -> Slice<Base> { get }
    public init(base: Base, bounds: Range<Base.Index>)
}