Shortcut deforestation in calculational form

In functional programming, intermediate data structures are often used to “glue’) together small programs. Deforestation is a program transformation to remove these intermediate data structures automatically. We present a simple algorithm for deforestation based on two fusion rules for hylomorphism, an expressive recursion pattern. A generic notation for hylo-morphisms is introduced, where natural transformations are explicitly factored out, and it is used to represent programs. Our method successfully eliminates intermediate data struc-tures of any algebraic type from a much larger class of compositional functional programs than previous techniques.