Prisms are Lenses through Options. They compose very similarly to Lenses and it is easy to convert a Lens to a Prism to compose Prisms from existing Lenses. Eve

Prisms are Lenses through Options. They compose very similarly to Lenses and it is easy to convert a Lens to a Prism to compose Prisms from existing Lenses. Every Lens is a very simple "degenerate" Reducer (a Lens is just a getter and a setter from one "state" to another), but Prisms feel even more like "real" Reducers because of the optional states that can be involved. So Prisms and Lenses are very common composable Reducers in some styles of FP.