Interesting how the post doesn't mention the word "side effect" once. To me, all of this could be summarized by "no side effect".
this is wrong! ocaml is a functional programming language with side effects.
What's functional programming all about? (2017)
61–70 of 158 posts
Re: What's functional programming all about? (2017)
#62As a programmer, I don't know if it's still relevant to make a strict separation between programming paradigms. You can use immutable types, pure functions, closures and so on in most languages. Conversely, you can define mutable types and imperative code in most functional programming languages. I'm always surprised reading comments on these topics, people saying they don't grasp FP. But don't we use higher-order fu…
I don't think we should think of things as having a strict separation, but certainly some languages push you harder than others toward certain programming paradigms, and some make other paradigms difficult or awkward to use.
For example, while I can do FP in Rust, I would not really call Rust a FP language. It does have some features that make doing FP possible, but a lot of the code I see (and write) is a mix of imperative and FP.
But if I'm writing Scala, I'm going to be mostly writing FP code, and the language helps me there. Recent versions of Java make it easier to write FP code if you so choose, though you'll still see a lot of people write more imperative code in Java.
(I think if Rust had Scala's for-comprehensions, I'd write more FP-ish Rust. I know there are crates that emulate them, but they're not the most ergonomic, and I don't want to write what ends up being unidiomatic Rust code.)
Re: What's functional programming all about? (2017)
#63Interesting how the post doesn't mention the word "side effect" once. To me, all of this could be summarized by "no side effect".
I think the point of the article is to illustrate why "no side effect" is important.
While I agree, you can get all of that FP example from the article in say C++ by liberal const-usage. So is "const-y" C++ functional programming?
Re: What's functional programming all about? (2017)
#64The article itself was well written, although I'd appreciate if the author was more "to the point" with the examples. FP never resonated with me and never fit the mental model I have for programming. I tried learning Prolog and Haskell a few times, and I never felt like I could reason about the code. This line from the article: "[..] With functional programming, whether in a typed language or not, it tends to be much…
I think I find a lot of FP code harder to both write and read (even code I've written myself), but when the FP code is written and compiles, it is much more likely to be correct.
It's an annoying trade off, to be sure. With a language that makes writing FP code ergonomic and idiomatic, though, I'm usually going to choose to write that way.
But even in languages where writing in an FP style is a chore (if it's even possible at all), you can take some lessons. The C I write today is more "functional" than 25 years ago, when I'd never even heard of functional programming. I try to avoid global state and mutation and side effects, and write more pure functions when I can. I think about my programs as transformations of data, not as a series of instructions, when I can. My C code today is not very FP at all when you'd compare it to something written in Haskell or Scala or whatever, but it's, IMO, "better" code than what I used to write.
In 2022 I went back to a C-based open source project that I used to work on heavily in the mid-'00s. Reading a lot of that old code makes me cringe sometimes, because the details at the micro level make it really hard to reason about behavior at the macro level. As I've been working on it and fixing things and adding features again, I'm slowly morphing it into something easier to reason about, and it turns out that using functional concepts and idioms -- where possible in C without having to go into macro hell -- is essentially what I'm doing.
Re: What's functional programming all about? (2017)
#65The article is not about FP.
> Languages like Java encourage patterns where you instantiate a half-baked object and then set the fields later.
Maybe it did before 2010. For many years everyone prefers immutable objects (so that object and its builder have different types, or in simpler case -- no setters, only constructor initialization). You can see it in pretty much all frameworks.
I'm ok with both functional and procedural languages, I just think this article is not about functionality. Come on, FP is all about monads!
Moreover, the "imperative" code example would be impossible anyway with immutable objects without side effects. So what I think the article is about is immutable data types. Everyone agrees that immutable are better, we have to do mutables only when we're optimizing for CPU/RAM.
And BTW concurrency is typically easily achieved if variables were not plain objects, but Future/Observable/Flow/Stream -- pick your poison. They all have passed the hype hill already, and became "just a tool" I think.
Re: What's functional programming all about? (2017)
#66The article is not about FP. > Languages like Java encourage patterns where you instantiate a half-baked object and then set the fields later. Maybe it did before 2010. For many years everyone prefers immutable objects (so that object and its builder have different types, or in simpler case -- no setters, only constructor initialization). You can see it in pretty much all frameworks. I'm ok with both functional and p…
Define what you mean by "everyone" -- there are times where the cost of immutability can be overwhelming, such as in high traffic systems with overly complex data structures which you are required to use because someone who should have known better insisted upon writing.
(sorry, bitter personal experience) And yes, that is explicitly "modern" Java code written by a lead engineer and "java champion" in 2023.
Re: What's functional programming all about? (2017)
#67Missed the key point: FP serves to make someone feel like they're smarter than someone else.
Re: What's functional programming all about? (2017)
#68As a programmer, I don't know if it's still relevant to make a strict separation between programming paradigms. You can use immutable types, pure functions, closures and so on in most languages. Conversely, you can define mutable types and imperative code in most functional programming languages. I'm always surprised reading comments on these topics, people saying they don't grasp FP. But don't we use higher-order fu…
There is an interesting trend where things with a strong mathematical definition tend to have the advantage. "Functional Programming" doesn't have a precise definition at all as far as I know, so it is likely it doesn't refer to a real thing. Most of the paradigms are similar as they don't seem to actually mean anything. People seem to want to describe something (in today's article, data flow) but they don't quite have the language to do it.
If you go to https://en.wikipedia.org/wiki/Functional_programming right now you will see "functional programming is a programming paradigm where programs are constructed by applying and composing functions" which is a bit of a ... it is quite hard to program without doing that. Even SQL is basically applying and composing functions. There are languages that are branded together because they have similar communities or techniques, but the brand isn't describing something beyond people thinking that things belong in a basket together.
Re: What's functional programming all about? (2017)
#69It’s hard to characterize what fp is. A lot of people think fp is a bunch of techniques like map, reduce, immutability or high level functions or monads. None of those things are exclusive to fp. They are just tricks developed by fp. Here’s how to get a high level characterization of what fp actually is: You know how in math and physics they have formulas? Formulas for motion, for area, etc. Functional programming is…
> Functional programming is about finding the formula for a particular program.
Can be disproved trivially. Anyone can code up a program that generates the nth prime for some n, by iteratively accumulating n primes starting from 2 using trial division. otoh, an actual formula that produces the nth prime would be an earth shaking event.
Re: What's functional programming all about? (2017)
#70As a programmer, I don't know if it's still relevant to make a strict separation between programming paradigms. You can use immutable types, pure functions, closures and so on in most languages. Conversely, you can define mutable types and imperative code in most functional programming languages. I'm always surprised reading comments on these topics, people saying they don't grasp FP. But don't we use higher-order fu…
There is an interesting trend where things with a strong mathematical definition tend to have the advantage. "Functional Programming" doesn't have a precise definition at all as far as I know, so it is likely it doesn't refer to a real thing. Most of the paradigms are similar as they don't seem to actually mean anything. People seem to want to describe something (in today's article, data flow) but they don't quite ha…
It's funny you say that because I'd say FP has a much more well defined mathematical foundation compared to OOP. In fact, before it became as dominant as it is today, it was often criticized as being too scholarly and theoretical. It's built mostly on the foundations of Lambda Calculus (and maybe some Type Theory).
I don't think OOP ever had nearly as strong of a mathematical/scholarly foundation as FP has