Ever since my first encounter with Haskell in my very first week at university I have been waiting for functional programming to become more widely spread and to find acceptance in the industry. Still… waiting…
Playing around with Scala these days, I have come as close as ever to use functional programming for something non-academic. Is Scala a functional programming language? You bet. But isn’t it also an object-oriented language? Certainly. Arguably more so than other object-oriented languages like Java (link). This might be the foot in the door for functional programming. Because object orientation is so dominant and functional programming requires such a different way of thinking, it is basically impossible for functional programming to compete with the market leader. And what do you do if you can’t beat them? That’s right. You join them.
Object-functional languages like Scala provide the perfect ground for programmers, who know their object-oriented languages inside out, to get to know the benefits of functional languages. You can get your code working by programming in the object-oriented way you live and breath, then you refactor it and add some functional touch to it. Or rather, you remove some of the wordy cumbersome cruft replacing it by more elegant code. And once you get to know and love the expressiveness that is functional code you will start writing it in the first place. And with that become a better developer.
By now, I have stopped waiting for a breakthrough of a pure functional language. But with that I am also sure that things like higher-order functions and pattern matching will find their way into the mainstream. One way or another.