func `@`[T, U](s: HSlice[T, U]): seq
func sort[T](s: Slice[T]): Slice[T] {.inline.}
func span[T, U: Ordinal](s: HSlice[T, U]): int {.inline.}
func spans[T, U: Ordinal; V](s: HSlice[T, U]; x: V): int {.inline.}
func swap[T, U](s: HSlice[T, U]): HSlice[U, T] {.inline.}
func to[T, U](a: T; b: U): HSlice[T, U] {.inline.}
iterator pairs[T, U](s: HSlice[T, U]): auto {.noSideEffect.}