Recently, I watched this great talk by Gilad Bracha in which he, among other topics, criticizes the functional programming culture. The talk really resonates with me as I had a similar experience with my foray into functional programming. This is why I want to share some other interesting sentiments & links about the unpleasent side of this culture in this article.
As an aside, the title is directly inspired by the talk as sometimes you do get the impression of dealing with cultists. There are, of course, reasonable advocates of functional programming but somehow functional programming attracts a lot of unreasonable advocates which this article focuses on. And the worst offenders are the Haskell cultists.
There are countless examples of attacks on “heretics”, i.e. people that criticize functional programming in the slightest. A recent report of a functional programming expert’s personal experience with such an attack of the cultists exhibits their viciousness. Suprisingly, not even functional programming experts are spared. There is another article by the same author in which he criticizes monads and pure functional programming that also resonates a lot with me since I made some similar points in my own previous articles.
The following quote illustrates the essence of the cultists quite well in my opinion (source):
Haskell I am ready to dispense as a failure at this point, having actually (tried to) use it since 2006. I really think people should try writing large programs with Haskell before advocating for it.
Functional programming is so overpromised by its advocates that the uninitiated (my former self included) become so sure that it must be the revelation that verifying these claims, for instance by actually programming something bigger in Haskell, seems wholly unnecessary. These newly converted cultists become (often especially condescending) advocates themselves and only worsen the problem as it is. There is even a commonly used term describing (a subset of) the people affected by this phenomenon: haskell zealot.
To sum up, if you follow discussions where functional programming is a topic be aware of the cultists and be sceptical of overly bold claims. And become very sceptical of participants in the discussion that talk down on anyone that even utters the slightest criticism against functional programming.
The following are further relevant links I found after having published this article.