docs/datatypes/oneand.md
API Documentation: @:api(cats.data.OneAnd)
The OneAnd[F[_],A] data type represents a single element of type A
that is guaranteed to be present (head) and in addition to this a
second part that is wrapped inside an higher kinded type constructor
F[_]. By choosing the F parameter, you can model for example
non-empty lists by choosing List for F, giving:
import cats.data.OneAnd
type NonEmptyList[A] = OneAnd[List, A]
which used to be the implementation of non-empty lists in Cats but has
been replaced by the cats.data.NonEmptyList data type. By
having the higher kinded type parameter F[_], OneAnd is also able
to represent other "non-empty" data structures e.g.
type NonEmptyStream[A] = OneAnd[Stream, A]