Applicative shortcut fusion

Abstract

In functional programming one usually writes programs as the composition of simpler functions. Consequently, the result of a function might be generated only to be consumed immediately by another function. This potential source of inefficiency can often be eliminated using a technique called shortcut fusion, which fuses both functions involved in a composition to yield a monolithic one. In this article we investigate how to apply shortcut fusion to applicative computations. Applicative functors provide a model of computational effects which generalise monads, but they favour an applicative programming style. To the best of our knowledge, this is the first time shortcut fusion is considered in an applicative setting.