Abstract

One big critique of functional programming is that the beginner is quickly bombarded with scary-sounding categorical terminology like functors and monads. Well, in 2008, Conor McBride and Ross Paterson decided to introduce a new abstraction called strong lax monoidal functors into the FP vocabulary, just to make the situation even worse. Now commonly called applicative functors, they sit neatly between functors and monads in the effectful programming abstraction hierarchy, providing a weaker notion of computation that makes them more widespread than full-fledged monads. In this talk I will motivate and introduce applicative functors, explaining what we gain and lose by constructing programs in an applicative, rather than monadic style. I will also present their categorical analogue and how it relates to applicative programming.