The Myth of OOP/FP Compatibility

It’s a common misconception that choosing between Object-Oriented Programming (OOP) and Functional Programming (FP) is a false dilemma, suggesting that practitioners can seamlessly integrate both paradigms. But this is like saying that stick-built homes and steel-built homes are compatible because they both end up looking the same, or that electric and combustible engine cars are compatible because there are hybrid vehicles.

But even though two homes may look the same on the outside and have the same floor plan, a stick-built one is made from wood - not steel. Similarly, hybrid vehicles combine elements of combustion and electric power, yet this doesn’t imply a complete compatibility or interchangeability between the two power sources. Consider how long Toyota had been making the Prius before they entered the BEV fray. If it were the case that the two technologies were wholly compatible, then Toyota‘s first fully electric vehicles should have ran with the industry veterans such as Tesla, but reviews indicate Toyota has a few years of honing and learning to do before they can fully compete.

Similarly, FP represents a paradigm with a unique set of principles and methodologies, rather than a mere collection of stylistic preferences that can be adopted or discarded on a whim. Unlike OOP, which is often characterized by its use of objects and encapsulation, FP emphasizes concepts like functional purity, referential transparency, immutability, and a preference for expressions over statements, encapsulating logic in a way that avoids side effects. While integrating FP concepts such as immutability into OOP can enhance code quality and maintainability, doing so does not transform an OOP-based architecture into a functionally programmed system. The essence of FP involves a holistic approach to software design, requiring specific architectural decisions and specific data structures that are fundamentally different from those in OOP. Just as a house’s structural integrity depends on the materials and techniques used in its construction, and a hybrid car’s performance is constrained by its underlying combustion engine, applying FP principles in an OOP context does not change the foundational paradigm. The house is still made of one material, not the other. The car still has the mechanics of a combustion engine vehicle, and the maintenance schedule of one too.

Choosing OOP while drawing inspiration from FP practices is neither incorrect nor improper. However, suggesting that this blend is utilizes both paradigms to any meaningful extent is an oversimplification - as the OOP paradigm will ultimately influence the guiding principles of the design and implementation. Such a viewpoint not only does a disservice to novice developers by potentially obscuring the rich, underlying principles of FP but also limits personal growth by restricting the exploration of FP’s distinct approach to problem-solving. Embracing FP in its entirety requires a shift in mindset that can profoundly influence how one conceives of and constructs software. By truly understanding and applying FP, developers can unlock new perspectives and methodologies that complement their skills in OOP, leading to more robust, maintainable, and scalable solutions. Encouraging a genuine curiosity and understanding of FP among developers at all levels enriches the software development community, fostering a more versatile and nuanced approach to programming.