[sidlls]

"FP" camps tend to come in two flavors: "I'm a mathematician writing a computer program, and all problems will be made to look like math problems even if it means the program becomes an inscrutable mess of types and dense syntax" and "functional-ish idioms are included". The latter is useful, sometimes, for cloud computing and parallel computation; the former tends to have too many problems (slow build, slow execution, poor jargon laden syntax, etc.) to be very useful outside of academia.

I am (perhaps obviously) biased, here, but I tend to just roll my eyes whenever any of my colleagues suggests we should use functional programming to solve a problem. There are actually very few real-world use cases where it's objectively better.

[epgui]

> all problems will be made to look like math problems

All problems that can be solved with code are math problems. Proofs and programs are isomorphic (see the Curry-Howard correspondence).

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Edit: this is a factually accurate comment, delivered dispassionately. It's not controversial or new-- it's something we've known for longer than the C language has existed. Why the downvote? Like I said, see this: https://en.wikipedia.org/wiki/Curry%E2%80%93Howard_correspon...

[AnimalMuppet]

Factually accurate (to some degree), but almost completely irrelevant.

First, not all problems that can be solved with code are math problems. Take driving a serial port, for instance. There might be some aspects of it that are mathematical, but mostly it's a matter of interfacing with the chip spec.

Second, even for problems that are isomorphic to a math problem... the thing about isomorphisms is that they aren't identical. One form or the other is often easier to deal with. (That's one of the reasons we care about isomorphisms - we can turn hard problems into easier ones.)

Well, which is easier, writing programs or doing proofs? Almost always, writing programs is easier. This is why it's (almost) completely irrelevant.

Nobody wants to write code that way. So nobody cares. They're not going to care, either, no matter how forcefully you point out Curry-Howard.

Now, as you say elsewhere, you can gain insights from math that can change your code. That's true. But I suspect that most of the time, you don't actually write the code as a proof.

[sidlls]

This is like saying all physical engineering problems are quantum mechanics (or insert other physics theory) problems. It’s technically correct (the best kind of correct), but misleading and useless as a matter of practice.

[aeonik]

Your analogy is interesting to me.

I definitely see the parallel, but I'm not actually sure this is true.

A lot of the deep functional stuff I'm learning right now are more about finding connections and shortcuts between things that we used think were different.

For me, comparing functional programming to older languages is more like comparing "tally marks" or "roman numerals " to a modern "place value system".

Now back to the physics analogy. The gap between quantum physics and chemistry is both a theoretical and computation limit.

There are also seen to be very distinct layers where the lower level don't seem to correlate with higher levels.

But I can also see this might apply to the Curry-Howard correspondence.

Hmmm. I have to think about it more...

[epgui]

I see what you’re trying to do with the comparison, but it’s not really the same.

In your example, the two things are separated by at a minimum one layer of emergence: your example is more like saying biology is just chemistry. In maths and programming, they are both at the same level, no emergence.

I also haven’t found what you say to be true at all— As I’ve been learning more maths and more programming, and learning more about the link between the two, I have found that the ability to see problems from more than one angle has had a dramatic impact on how clearly I think and how efficiently I solve problems. Not useless whatsoever.

[sidlls]

I was an academic physicist for the first several years of my post-graduate school career--I, too, see much value in having multiple perspectives to a problem.

But that's quite different from your other claim. Maths and programming are not at the same level. When one writes a "hello world" program, math does not figure into the final text of the code at all. Similarly, when one writes code to implement a system interacting with multiple dependencies, one is not doing mathematics, except in the trivial sense of your original comment. That is to say, at such a remote distance that it's meaningless to describe the activity as a mathematical one.

[baq]

You’re doing theorem proving in all cases where you handle errors or exceptions in non-trivial fashion. Same when you’re implementing any kind of authz. When dealing with async code or threads, you’d better be good at your invariants. This is all discrete maths. Yes I don’t differentiate continuous functions at work but let me tell you juggling multiple condition scenarios when integrating multiple inputs with multiple systems is damn close to working with logic proofs.

[epgui]

I completely disagree, but I don’t have the energy to argue or explain.

[slotrans]

Interesting. Functional programming is the only strategy I've seen be successful at building business software. (Hint: you can do FP in Java and it's not even awkward, and SQL is inherently functional).

[sidlls]

I work at a FAANG-like company. The code base has almost no functional programming paradigms deployed. It’s a multi-billion dollar company from which I, an IC cog in the machine employee, became a multimillionaire through from the IPO. It’s wildly successful.

[ralphc]

Is it all design-patterny OOP?

[sidlls]

The vast majority of it is, unfortunately. That's starting to change, though, as we are hitting some pretty severe maintenance and performance issues, as well as being bottlenecks to making changes, that all the abstraction is obviously the root cause of. None of the services the team I used to lead utilized OOP (in the sense you're referring to), and the new team I lead will be making sweeping changes to move away from it under my guidance.

It served its purpose, but we've outgrown it.

[wredue]

Is “wanting evidence for constant silver bullet claims that never actually pan out” really “obviously biased”?

It’s not just you. Functional Programming really does not adequately solve any of the problems that its advocates claim while refusing to provide any evidence.

And it’s not “biased” to write these claims off.

[epgui]

I don't know what "silver bullet" claims you've heard, but I'm not sure how that is relevant to this thread. I don't think I've made any outlandish claims, or any claims that aren't substantiated by a preponderance of academic literature.

[roenxi]

I find this whole thread fascinating because nobody seems to have identified what functional programming is defined as (programmers can just use functions to code and end up with functional programming, it isn't an obscure style), who the advocates are or what they claim.

And yet, without any substance, the debate rages.

[epgui]

> nobody seems to have identified what functional programming is defined as

Nobody asked (until now, so thank you for asking!), and this is a fairly well discussed topic for anyone who cares to search!

You will probably get a lot of slightly different answers depending on who you ask or where you look, but I think a very strong common thread is "referential transparency". Functional programming gives you that, and that is the property that makes FP particularly well suited for parallel computation. Referential transparency is related to the concept of "function purity" (in the sense that either one usually guarantees the other), which you will often hear people talk about as well. The two concepts are so intimately tied that sometimes I wonder if they're two different perspectives on the same thing.

This, along with the fact that FP has been an active area of research (an important part of innovation) for a long time, is why I brought it up.

https://en.wikipedia.org/wiki/Functional_programming

https://en.wikipedia.org/wiki/Pure_function

https://en.wikipedia.org/wiki/Referential_transparency

https://softwareengineering.stackexchange.com/questions/2938...

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> programmers can just use functions to code and end up with functional programming, it isn't an obscure style

That's not how it works. Note that functional programming has nothing to do with merely "writing functions".

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> without any substance, the debate rages

The substance is there and there is plenty of it, but learning requires work.

[arzke]

> Referential transparency is related to the concept of "function purity" (in the sense that either one usually guarantees the other), which you will often hear people talk about as well.

Isn't referential transparency (the property of a function that allows it to be replaced by its equivalent output) a consequence of function purity? In other words: could a pure function not be referentially transparent?

Also, I remember Robert C. Martin describing the functional programming paradigm as a "restriction upon assignment". I kind of like this definition as the rest seems to flow from it: if you can't assign, you can't mutate. If you can't mutate, you have pure functions, which are referentially transparent.

[corinroyal]

"Could a pure function not be referentially transparent?"

Yes there are pure functions which are not referentially transparent. A pure function with side effects, such as printing a result to standard output, is not referentially transparent. You can't replace the function with it's return value, since that doesn't replicate the printing side effect.

[wredue]

Functional programmers regularly claim:

-Haskell is faster than C (lol)

-FP gives you free concurrency

-FP makes code more testable

-FP is easier to read

-FP is easier to consume for people

-FP results in no bugs

-FP is easier to change

-FP will literally suck your peepee

-Actually FP is the second coming for Christ

It’s really funny how you also pretend you’ve never heard of all the silver bullet claims that are incessantly plaguing every programming forum.

What’s also really funny is your multiple alt accounts manipulating your votes. You must be real secure in those those claims.

[roenxi]

> -FP will literally suck your peepee

> -Actually FP is the second coming for Christ

On a style point, you've rather undermined yourself that these are common claims because there are entries on this list that are clearly fabricated, as well as others that look like wilful misinterpretations of what someone else said. That casts doubt on the more reasonable entries. There are annoying FP evangelists out there, but the overall tone pattern matches straw-manning.

You'd have made it easier for everyone taking the whole list seriously. Transparently mixing fact and fiction just makes it harder for people who aren't already part of a conversation.

[epgui]

I agree with some of these points, but none of them are claims I made in the context of this discussion, so I’m not sure why you’re even arguing about those. It’s irrelevant.

[wredue]

They’re false claims. And I didn’t bring up the false claims FP programmers make until you asked for it to happen. I simply said that rejecting the ridiculous silver bullet claims that FP programmers make is completely fine because they don’t provide any evidence and that which is asserted without evidence can be dismissed without it.

Not that that matter because all of those claims are demonstrably false anyway!

[tome]

> Functional programmers regularly claim:

> -Haskell is faster than C (lol)

If they regularly claim that you should easily be able to point to several recent examples. Can you?

[kaba0]

Then why has it been slowly incorporated into literally every mainstream PL? You do know you don't have to be an extremist, and your code can contain both FP, OOP and imperative parts, whichever makes the most sense? FP and OOP are not even opposites.

They absolutely solve real issues, and it's just sticking your head into sand to say otherwise.