> FP people are not bullying you, or shoving anything down your throat.
Have you ever worked with a FP evangelist? Every single experience I've had has been with a person who simply won't take "no" for an answer. The impatience, ego, and pettiness is bar none, really.
Aside from that, there are objective reasons to be skeptical: it's inefficient when it comes down to actual implementations that have to work on actual computers and solve actual problems ("but but tail recursion and copy optimizations lolol you moron you just don't understand it"). Also, most FP tends to become much more complex than an equivalent imperative program solving the same problem, usually through a terrible confluence of code density and mazes of type definitions.
As someone that's left scala and come back to dotnet land... depending on the domain, functional programming results in much cleaner solutions. A lot of the code messes in functional paradigms that I dealt with and also created were mostly due to people that didn't understand how to think functionally. It took a long time for me to figure it out. I find myself missing features all the time now, and spending a whole lot more time fixing bugs that simply wouldn't exist had people just applied more functional principles in their code. I understand where you're coming from with your frustrations, but I would personally attribute that to the LISP culture problem that I also saw with the hardcore functional programmers. Everyone would just nerd snipe themselves into re-inventing the wheel.
Also, my dotnet contemporaries on average do not care as much about code quality as people did when I was in scala land. But this might just be a company culture thing.
This rings true - experiencing different paradigms opens you up to more elegant solutions. That's why years later I now see the value of the "Programming languages" course I had in university - every lecture covered a new language and had homework to implement a program in it. I haven't touched LISP or Prolog since, but just being exposed to them made me write better code in "traditional" languages.
Agreed. I took a year (long ago) to learn lisp just to be exposed to a different way. And it has paid dividends in terms of providing alternate ways of thinking about code in other languages.
That said, I'd never want to use lisp in a real production project. Same for FP. Get exposed to these things, take the learnings and bring them into KISS boring production code that is fast and maintainable.
.net, and C# especially are absolutely fantastic tools for programming. The problem is just that they are embraced by large companies and that is where crappy engineers tend to congregate, in my experience. The bigger the company the easier it is to get lost in the crowd.
I enjoy functional programming, but I'm a wizard with C# and .net, and I can pull a much higher salary continuing to focus there. I can write my own fun stuff in Haskell for myself and will continue to enjoy corporate money.
It's also laziness and controversy. Unit testing is something aggressively pushed in many of these places, but then they continue to litter side effects, long flows, loads of complex objects, void methods, and more which inherently make it more difficult to test. FP guidelines help a lot of these cases, and you don't need to understand monoids, monads or any of that to grasp the concept of simple functions with clear output.
Meanwhile, FP is kind of a pain to connect things in, for most people.
Before learning FP I used to ask myself: "Assuming that by tomorrow my memory gets erased and my IQ diminishes by 50 points, will I understand this code?".
That's why I try to juggle the least amount of variables as possible at the same time, while trying to have my code to read like a cooking recipe or a very simple literature. From that, FP feels almost natural.
Even more so, I think that most software bugs and spaghetti code is made by people that were too confident on themselves. They thought they could handle a lot of random unrelated variables floating around all the time, while having their functions do a lot of random algorithms at the same time.
And yes, they could handle it. The first time. But, in the long run, most people forget, or they leave and another person ends up having to maintain it, and that super brief-and-clever code became an unmaintainable mess.
I'm trying to push unit testing, as a means to get rid of some of those negatives you pointed out. But it's not a panacea. And obviously, I don't want to test for the sake of it either.
... there are lots of optimizations available when you have immutable types and no assignment operator if you're curious.
Pure, immutable data structures might not be the right choice if you don't have the right language/tooling/runtime to take advantage of the benefits but they're there.
I have spent the time with Haskell to learn how to not just use it a bit, but program it idiomatically and with some fluidity. I think there is a very interesting point you can reach if you go 100% all the way in. There are some types of programs that you can write, like compilers, that are kinda painful and dangerous and quirky in imperative or OO programming and are just beautiful in full on, no compromises functional programming.
I am waaaaay less impressed by the half-assed "I borrowed a few paradigms and bashed them into an OO or multi-paradigm language but it's still fundamentally imperative" approach.
Reconceptualizing your entire program as consisting of recursion schemes and operations that use those recursion schemes, what I think the deep, true essence of functional programming as a paradigm is, is a very interesting and has a lot of interesting benefits hard to obtain any other way, along with some costs you might never otherwise think about if your mindset is too deeply into one particular world.
Rewriting a single for loop with five maps, reduces, or filters is nothing. It's a parlor trick. It buys you nothing of consequence. For avoiding bugs I almost never have, this requires a lot of extra syntax and costs huge runtime performance unless the compiler is smart enough to optimize it away.
That doesn't mean it's bad, per se. I use maps and filters as appropriate. In some languages, they're syntactically convenient, and if I'm mapping or filtering with something that is already a function anyhow, the performance issue is moot. I'm not saying this is bad and you should never use those things.
What I am saying is that is completely uninteresting as a "paradigm shift". Writing architecturally imperative programs with a light sprinkling of map and filter is nothing. Come back to me when your program is no longer architecturally imperative, and the top level of your program is now a two-line expression of a chain of mapMs and <*>s that represents your entire program. Now you have something fundamentally different.
Frankly, I think those who bang on about how vital it is to replace for loops with maps and filter chains have actually managed to miss the entire interesting point about FP. One could perhaps blame FP advocates for not explaining it very well with some justification. But it still is what it is. These people are banging on about how square a brick is, and how hard it is, and how nicely you can use one to bash things open, and how nicely you can polish up a brick if you want, but the point of bricks is that you can put them together to build walls. Sticking a couple of bricks in the middle of a mud hut leaves you with a weird looking mud hut.
The point of functional programming isn't map and filter; it is taking the class of things for which those are only two easy examples (and not even necessarily the most useful in general), and then building your entire program out of that class of things. You end up with something very different if you do that.
The linked article also bangs on about not having null references. Nothing stops you from having an imperative programming language that lacks null references. It is not a good or interesting example of why FP is interesting.
Anyways, upon re-reading, I lost a bit of focus on my original point, which is that you do need to watch out for which of the types of FP are being advocated. I have very different reactions between the two of "consider rewriting your fundamental view of the world to be composing recursion schemes instead of as the stringing together of imperative operations in various fancy ways" and "you shouldn't use for loops". You may not love the first; it is certainly a trip and not necessarily for everyone and everything, but it will at the very least expand your mind. The second is, well, mostly annoying to me because of the vigor of its advocates far out of proportion to either its programming utility or its mind expansion characteristics.
> The second is, well, mostly annoying to me because of the vigor of its advocates far out of proportion to either its programming utility or its mind expansion characteristics.
Thanks to closures, map/reduce function callbacks in Javascript are extremely handy.
Please link me to something like a stackoverflow answer with "vigor" greater than this, I'd love to read it.
If you want to see this for yourself, be it either because you don't believe or an honest intellectual curiousity, find a forum (StackOverflow isn't actually the best since it's not really a "forum") and express skepticism about the utility of map and filter and suggest that a for loop works just as well. Be polite, but be firm and don't back down.
You will be called names. You will be insulted and told that you just don't understand functional programming, probably because you're dumb.
I know this, because I had to deliberately cultivate a writing style that learned how to avoid this (which is why I start out waving around the fact that I don't just know a bit of Haskell, but actually know Haskell; I would not normally make a deal out of that, for instance). I wouldn't have had to deliberately learn how to write around this if it doesn't exist.
Now, the tradeoff I get is people who don't believe such advocacy exists, because it is no longer appearing in the replies to my posts like it used to. A worthy tradeoff even so, I think.
If you were to write a post about taking an example imperative program and showing the conversion to FP, I’d be very interested to read it. Or if you have a link handy to someone else’s post?
For me it’s difficult to immediately understand what you mean about the top level program, mapM, etc. I guess what you mean is that they entire program can be expressed as 1 call with some args? I feel like there is probably more nuance that I am not grasping.
I am curious to add this way of thinking to my toolbox, and I learn best by examples.
I have read things like Mostly adequate guide to FP and whatnot. They always get stuck on side effects and containers, which is fine, but doesn’t really address the larger scope of program design.
In the second part of the "Solving Problems the Clojure Way"[0] talk, the speaker shows step-by-step transformation of the heavy imperative (book-keepish) JavaScript code to a more functional approach.
As a result of transformation, ~95% of the code is easily unit-testable and the only impure code is the call to main which basically starts all the domino falling.
> people who have figured out that something is obviously beneficial?
If it's so beneficial then those people can prove it by building something exceptional. I worked with Haskell and Scala for almost a decade and libraries were full of bugs and performance problems. A lot of bugs just hadn't been reported because so few people were using them. FP certainly has its strengths but so far there's very little evidence that it produces better software in the long term.
The typical argument for vaccines is much less shaky than the typical argument for pure FP. For one, vaccine people can actually explain why vaccines are good. FP people seem to mostly just repeat variations on "it's easier to reason about" and showing trivial functions that are generally not easier to reason about.
Imagine trying to get people to accept vaccines, but in a world where we have other types of medicine that usually works well enough for all the things you've developed vaccines for, and the only argument you're allowed to make is "it's obviously better, look at how amazingly liquid the stuff in this syringe is".
You'll still get some resistance, but in our current world, pure FP is much more of a niche thing than pro-vaccine stances. There's a reason for that.
> The typical argument for vaccines is much less shaky than the typical argument for pure FP.
I suspect you aren't that knowledgeable about either.
> For one, vaccine people can actually explain why vaccines are good.
Unless you have a very particular background, I'm suspicious that you can actually follow the frontier of that argument. More likely, you're getting the ELI5 explanation.
> FP people seem to mostly just repeat variations on "it's easier to reason about" and showing trivial functions that are generally not easier to reason about.
Well-designed FP languages reify coherent low-complexity formal semantics. When FP advocates say "reason about", they mean in a (semi-)formal sense. No popular imperative language has any kind of denotational semantics, so good luck reasoning about the compositional behavior of C++ libraries, unless your definition of "reason about" is "think about informally".
> Unless you have a very particular background, I'm suspicious that you can actually follow the frontier of that argument. More likely, you're getting the ELI5 explanation.
People who actually understand complex things are able to provide ELI5 level explanations for people who haven't the background for more rigor. You're presenting a false representation of the OP's comment anyway: it never suggested the explanation for why vaccines are good required "frontier" level discourse.
> Well-designed FP languages reify coherent low-complexity formal semantics.
This is such a great example of what so many of us have noted about FP evangelists. It's so divorced from writing software as to be gibberish.
> It's so divorced from writing software as to be gibberish.
Only if the software you're writing is A) aggressively simplified, so as to be amenable to informal analysis, or B) garbage.
If you're only interested in writing garbage, or perhaps you don't even notice that's what you're doing, then the appeal of FP is significantly reduced.
Yes, in theory, and this sometimes works. But it rarely works in general.
In practice, people come to your explanation pre-conditioned with a lot of (often politicized) misinformation, Dunning-Kruger type overconfidence in their own ability, very little curiosity or openness to new ideas, and exhibit the attention span of a 26th percentile squirrel.
People tend to listen very little and are more skeptical of others than they are of their own understanding: instead of searching for ways in which their mental models need adjusting, they try to poke holes in your explanations. They'll repeat whatever objections they've seen or heard somewhere, whether or not the objection is relevant or adequate. This undermines both "ELI5" approaches (because what you gain in simplicity you lose in nuance and correctness) and more pedantic approaches (which require more prerequisite knowledge, experience, or patience).
If you disagree with me because that is not your experience, it's possible you surround yourself with unusually insightful and wise people.
It simply can't be done. It's always possible in theory but never in practice. Or at least certainly not in this special snowflake case.
Until someone bucks the trend and does it.
But for that you need someone with actual intelligence and empathy; a Feynman of that sphere so to speak.
In every gatekeeper community this is the order of things until someone finally destroys the gates to the knowledge and the monopoly of the priesthood. Until then, it's basically "blame the victim" for their own lack of understanding (e.g. "people listen very little", "people are more skeptical of others", "they try to poke holes in your explanations", "They'll repeat whatever objections they've seen or heard somewhere", etc).
Well, I don't disagree with you, but also all of these things you list in the parentheses are just how humans generally behave. They are real obstacles.
And regardless of where we place the blame, at the end of the day:
> In life, there are a lot of obvious things that are very difficult to teach.
> there's very little evidence that it produces better software in the long term.
Have you used other software? 99% of it is dogshit.
> libraries were full of bugs and performance problems
This is a really wild claim to me. IDK about Scala, but libraries in Haskell, Ocaml, and Elixir are all vastly better than libraries in C++, Java, Python, despite a smaller userbase.
>figured out that something is obviously beneficial?
Case in point for the problem with FP communication. When you speak in smug absolutes, it comes off as religion.
I'm pretty big into the FP world. I love Purescript. I dig Idris and exploring dependent types. I spend a lot of time at work teaching "functional" thinking. And yet, I still find most "hard core" FP evangelists insufferable for smugly explaining things as "obviously beneficial." ugh.
That is a lots that sucks about pure FP. It's not all upsides. The FP community can do a lot better at "evangelizing" by talking like engineers rather than sales people.
Where did I say that FP was obviously beneficial? You're reading too much into my question. I was questioning the GP's epistemology.
> talking like engineers rather than sales people.
They do talk like this - go to any Haskell conference and it's 90% engineering papers - much better than e.g. a JS conference. It's just that most people don't even know what PL engineering even looks like, let alone how to interpret it.
If you believe in the epistemic power of "studies" to convey useful information in these domains, I have bad news for you - you are the one in a religious fervor.
The only semi-objective metric you've proposed is compiled code performance, which is a fairly small component of most people's utility function, especially when the difference disappears in all but numerical-computation-centric applications.
Have you ever worked with a FP evangelist? Every single experience I've had has been with a person who simply won't take "no" for an answer. The impatience, ego, and pettiness is bar none, really.
Aside from that, there are objective reasons to be skeptical: it's inefficient when it comes down to actual implementations that have to work on actual computers and solve actual problems ("but but tail recursion and copy optimizations lolol you moron you just don't understand it"). Also, most FP tends to become much more complex than an equivalent imperative program solving the same problem, usually through a terrible confluence of code density and mazes of type definitions.