84 What You Needa Know about Yoneda Profunctor Optics and the Yoneda Lemma (Functional Pearl) GUILLAUME BOISSEAU, Department of Computer Science, University of Oxford, UK JEREMY GIBBONS, Department of Computer Science, University of Oxford, UK Profunctor optics are a neat and composable representation of bidirectional data accessors, including lenses, and their dual, prisms. The profunctor represe