Same as Infix, except the monad type has three arguments. The second and third are always just passed through.
type ('a, 'd, 'e) t
val (>>=) : ('a, 'd, 'e) t ‑> ('a ‑> ('b, 'd, 'e) t) ‑> ('b, 'd, 'e) t
val (>>|) : ('a, 'd, 'e) t ‑> ('a ‑> 'b) ‑> ('b, 'd, 'e) t