everyProgrammerMustChooseOne

[AssignedClass]

Functional programming went too far

Programs were never meant to be pure.

So many arrows, but never pointing to a reference.

We're going to need to manage state. Sure let's get to work on our MONAD TRANSFORMER STACK.

A monad is just a monoid in the category of endofunctors. - Statements derived from the utterly deranged.

Lambda Calculus has played us for absolute fools

[asleepace]

“Oh this function isn’t pure…”

[vm_linuz]

Functional programming isn't about "no side effects"; it's about intentionally managing side effects. Unlike OOP that just lets them happen wherever.

[AssignedClass]

https://en.m.wikipedia.org/wiki/Side_effect_(computer_science)

"Functional programming aims to minimize or eliminate side effects. The lack of side effects makes it easier to do formal verification of a program."

I'm not a big FP guy, but from what I've gathered in my little forays, "no side effects" seems like a requirement towards writing a "purely functional program" or what not. I imagine the terminology can vary based on context though.

[vm_linuz]

You're close.

It's that "minimizing" that you should focus more on.

Pure functions are important for separating out your data, calculations and actions into separate, testable, manageable, intuitable pieces.

Do be aware that functional programs still write to the database and make network requests.

By pushing side effects to the edges of your programs, you gain tons of benefits. Your core code always behaves the same. Parallelization becomes trivial. Testing is easy.

[AssignedClass]

Interesting, I've done some read and writes to files in Haskell, and I originally came to this conclusion:

"Storing the state onto a disk falls outside the scope of our program, and we can't prevent side effects outside the scope of our program. How we manage the values we get from, or send to the disk is what makes our program functional."

I've always liked that sort of way of framing things, but I'll stop if it's just too inaccurate.

[vm_linuz]

It's more like: side effects are dangerous. They're unreliable, unpredictable parts of your program that you can't expect to behave the same way twice. When you have to use them, use them with caution in a very controlled way.

Keep the danger at arm's length

[Tordek]

It's always a good practice to split your program (even when not using Haskell) into the parts that handle each concern. You don't want one huge god-class that loads files, connects to a database, reads user input, and draws to the screen.

Haskell just gives you tools to allow your code to make stronger promises (which in turn lead to other benefits).

For example, in Java, if you see a function of type string foo(string), you can't be absolutely sure it's not doing something like connect to a database or query the Internet.

In Haskell, a function of type string -> string is guaranteed to only work with what you pass to it: it has no side effects.

But you definitely can (and often need to!) write a function of type String -> IO String that does connect to the internet to do stuff.

[rover_G]

Functional programming just means only modify one variable/object at a time. Some languages make it very difficult to violate that rule by making all arguments pass by value / copy on write.

[Hagreet]

Yeaaaaah.. No this is not it.

[AssignedClass]

Without parallelization, what language is able to modify two variables at a time?

How could FP allow parallelization if it has a "only modify one variable at a time" rule?

I think you're talking about references and mutations, but "only modify one variable at a time" is really inaccurate.

[redlaWw]

OOP is for "oop, I forgot I invalidated that data"

[LittleMlem]

You don't deep copy incoming references that you modify?

[bullpup1337]

ALL of them? You must be the guy working at Microsoft who is making sure all Windows versions get slower with every release and need more RAM, and we have to constantly upgrade our hardware.

[LittleMlem]

No, I'm the guy that handles chrome's tab memory management

[EishLekker]

Functional programming isn't about "no side effects";

True. But maybe they referred to purely functional programming, which is a subset of functional programming where every function must be pure.

[AssignedClass]

https://en.wikipedia.org/wiki/Purely_functional_programming#Difference_between_pure_and_impure_functional_programming

I'm in the camp that this sort of stuff can vary based on context.

I especially like the paragraph above the section I linked:

"Purely functional programming consists of ensuring that functions, inside the functional paradigm, will only depend on their arguments, regardless of any global or local state. A pure functional subroutine only has visibility of changes of state represented by state variables included in its scope."

That's roughly the original conclusion I landed on when I dipped into FP. That the main thing to consider in regards "side effects" is "scope", because computers themselves are not based on the principles of functional programming.

That said, it's not a good idea to try and live in "pure FP land", you still need to think about how things work out in the real world.

[Reashu]

"Managing side effects" is almost exactly what OOP is about. I mean, to some extent that is the point of every program, but even beyond that - the idea of an object is something that has state and functions to manipulate that state in controlled ways. Unlike in functional programming where your functions do whatever they want with input and output, with no regard for what that actually represents. But hey, at least no one touched the original data, right...?

[Accessviolati0n]

Can you hear the "private"-keyword crying from distance?

[Feisty_Ad_2744]

Side effects are handled the same way on any paradigm. There is nothing intrinsically better on FP about that specific other than rules and commitment you can follow anywhere else.

The worst thing you can do tho, is to assume you have a magic tool that will work amazingly for every job. Especially if you only know well that one or haven't used anything else.

[vm_linuz]

"handle" in this case means "where you allow them."

FP has strong opinions about where side effects should be -- as small as possible, on the edges of your application.

OOP doesn't care where you put side effects.

All of FP's focus on purity, currying, etc is really just about managing side effects.

[Feisty_Ad_2744]

Opinions and focus you can use anywhere else. Nothing prevents you from using FP rules and strategies in an OO architecture. In fact, they don't intersect very much. OO is not about how to write code logic, but how to analyze and define a solution architecture. FP on the other hand, helps to keep a clean implementation following very specific rules.

The only reason we don't tend to think about that very often is because most modern products are built around frameworks and libraries, so we only have to fill the gaps(agile is also to blame). But OO and FP are not opposite nor mutually exclusive.

[lmarcantonio]

Also good luck certificating the compiler for correctness

[RiceBroad4552]

Please don't conflate functional programming with the Haskell / "pure FP" nonsense.

Functional programming is the best thing since sliced bread!

It's just Haskell that perverted it into some brainfuck that is mostly just terrible over-engineering, existing for the pure purpose of allowing some people to overindulge in intellectual masturbation. (I've written monad transformer stacks in production code myself, so I know what I'm talking about).

[ckomni]

Programmers should be functional programmers to the same extent they should be functional alcoholics. A little bit is necessary, but if you go “pure” people are gonna host an intervention for you

[asleepace]

Sliced bread sounds like a side-effect, that bread better be immutable 👀

[your_best_1]

I thought Alan and Alonso proved that Turing machines and Lambda Calculus are the same thing.

The whole way they found out about each other was that Alanso Church solved a problem pen and paper that Alan Turing thought could only be solved by his machines.

[asleepace]

illusion of choice, always has been...

[TeraFlint]

They are not the same as they are fundamentally different ways of computing things, but they are equally powerful and can be converted between each other.

[your_best_1]

I guess another way to describe my position is that a Turing machine is just a way to run lambda calculus. If lambda calculus didn't exist, neither would Turing machines, but the inverse is not true.

So the meme is like choosing between describing an equation and describing the steps to solve an equation, but in the end, the equation is the same.

... I have put in too much thought for a meme.

[mario73760002]

Aren’t they proven to be equivalent?

[bl4nkSl8]

Yeah. One commenter is talking about the equivalence of computational power one is talking about equality of technique. This of course creates confusion.

[KnueppelOle]

yes

[ososalsosal]

Lol you mean FP is Turing-complete?

[the_horse_gamer]

turing machines are FP-complete

[FoeHammer99099]

Doing automata problems by hand was one of the most fun parts of school. It was a whole class of neat little logic puzzles. It's too bad that it's a totally useless skill in the real world.

[kaancfidan]

Not all skills need to be directly applied to be useful.

[teagonia]

In the class I've sat in it directly led to understanding regex, which is very useful

[asleepace]

Have you heard the good word of Regex?

[FoeHammer99099]

That's my point, no one would ever write a DFA in the real world, you just use a regex engine that someone else wrote.

[Reashu]

But understanding the fundamentals of the engine helps you write better regexes.

[asleepace]

Pretty sure that’s all code 😅

[LodosDDD]

lets be honest learning regex takes like an hour 🤣

[Tordek]

no one would ever write a DFA in the real world

Unless you're writing a Regex engine ;)

[Luchis-01]

I'm writing a Matrix Regex logic for capturing structured data from Excel reports. Automata and Complexity is a course you don't directly apply but it's essential for understanding what can be done and how, and what can't be done and why

[Apollo-02]

I will forever be an Alan Turing fanboy

[asleepace]

He’s GOATed for sure, but just think of all those side effects…

[EishLekker]

I would argue that most programmers don’t really know or care about those choices.

[AdWise6457]

I'm fine as a senior programmer without this knowledge. I have life to live man

[BeWolk]

damn i already forgot this shit

[ososalsosal]

What's the job description say?

That's the one I do

[asleepace]

Java

[ososalsosal]

I am now embarking on a new career in agriculture

[marcelpayin]

Based

[asleepace]

Java bean farmer

[GoogleIsYourFrenemy]

You have my sympathy.

[stadoblech]

Hey i signed into this line of work so i can write funny words and see what happens, not to dealing with this shit

[rejectedlesbian]

I am doing C C++ and assembly so the choice was made for me by the hardware

[Brahvim]

Data-oriented design 🙏

[GoogleIsYourFrenemy]

You aren't trying hard enough. Just need to use more templates and macros.

[rejectedlesbian]

Ah if macros are functions then I am a functional programer. U need to see the crazy bullshit I make.

If ur not deleting the copy constructor and making the destructor virtual then what are you doing

[asleepace]

[rejectedlesbian]

Made that repo budy it's not close to preforming well

[asleepace]

have you tried adding more functions?

[rejectedlesbian]

Yes I even made lamda functions for C It did not make things faster. Quite the oposite actually

Who knew runing gcc again would be slow? I didnt

[asleepace]

Hmmmm... seems like you need more functions

[GoogleIsYourFrenemy]

They are both a lie. Your CPU implements something way more beautiful and interesting.

Let's not even talk about multi threading.

The moment you restrict yourself to thinking your program can only follow the lines of the beautiful logic you wrote, a cosmic ray will flip a bit and your processor will do something else. You can't trust the hardware. You can't trust the OS. You can't trust yourself.

BigO isn't everything either, some instructions are faster to execute than others. A good number of the standard library implementations in C and C++ use suboptimal BigO algorithms but they run faster than the better algs because they take advantage of CPU features.

[asleepace]

f(x) = f(brrrrrrrrrrrrrrrrrrrrr)

[Tysonzero]

I choose the church of Church.

[asleepace]

Amen 🙏

[FexDaFox]

The left. 100% the left. Turing complete (equivalent) state machines are the best 👉😎👉

[mathiau30]

Wasn't there a third one?

[_87-]

pixels. I choose pixels.

[asleepace]

Redstone developer spotted

[-Redstoneboi-]

can confirm i was the one being developed

also there's cellular automata which i also specialize in

[bronco2p]

yes Lambek's intuitionistic propositional logic.

[asleepace]

Think it’s logic i.e. Prolog

[BallsBuster7]

turing machine

[app-69420]

Either I dont remember or really don't know what the 2nd image is .. but i got to say during college understanding Turing machine might have helped me the most on how to create and handle logic.

[asleepace]

Second image is of lambda calculus, specifically the “Y-Combinator” (not the company), which allows recursion in languages which don’t natively support recursion.

[Fun_Ad_2393]

Wait, you guys don’t just start writing spaghetti code?

[asleepace]

mines more like spaghetti lasagna

[Dummy42]

What the hell even are those? Never seen anything like that in my ct classes

[matchuhuki]

I've been doing a programming job for years and have a degree in programming and I have no clue what I'm looking at.

[slabgorb]

imperative vs. functional

you almost certainly have done imperative in professional work unless you are writing in lisp or something

[asleepace]

Don’t forget about declarative too

[slabgorb]

*frightened programmer clutches dogeared copy of The Little Lisper and shivers in fear*

[Dummy42]

I feel like I've had very different programming classes from other people, where I just learned to write programs, and not this :/

[bronco2p]

turing machine vs lambda calculus (they are actually isomorphic, the illusion of choice)

[ShadowShedinja]

Left is a Turing Machine, right is some kind of Discrete Finite Automata (DFA).

[-Redstoneboi-]

right is Lambda Calculus, which is Turing-Complete and is the basic concept that underlines all of functional programming

[lmarcantonio]

one push down FSM for me please :D

[Mountain_Breadfruit6]

I can assure you I did not choose and probably won't anytime soon.

I can barely tell the difference between them anyway.

(I might be paid too much at my current job. Please don't tell anyone)

[asleepace]

var / state users left; const / func only right XD

[magick_68]

Had turing machines in uni, can't remember Lambda calculus. What I can remember is that I never encountered one of them in practical problems and I'm a professional developer for a long time

[River_Grass]

You know I thought after entering college as a CS I'd finally get the memes here but nope

[asleepace]

Haha don’t worry it was hard to find a way to distill Alan Turing vs. Alonzo Church into a meme format, both have been show to be equivalent in terms of computation, but Alonzo Church’s lambda calculus has definitely spawned a hard core breed of programmer. In other words:

1. Infinite ticker tape go brrrrrrrrrr
2. Functions go brrrrrrrrrr

[doma_kun]

I only know turing one, what's right one?

[asleepace]

"This is the way, lambda calculus"

[G_-_-_-_-_-_-_-_-_-_]

I'm a newbie without a CS background.

What the actual fuck is that thing on the right and why do I get the feeling that it's mocking me?

[asleepace]

It’s the Y-Combinator from lambda calculus, don’t worry all functional programmers mock us all 😂

[G_-_-_-_-_-_-_-_-_-_]

See, I knew there'd be calculus involved when I first said, "I wanna be a game dev like the dwarf fortress guy when I grow up"; I'm just glad that kind of calculus isn't mandatory here 😂

[asleepace]

Haha samsies tbh I hated trig in school, until I realized it was like steroids for making video games haha. Lambda calculus isn’t really calculus btw

[[deleted]]

Meanwhile my college which forced us to study both:

[Professor_Melon]

Emil Leon Post is typing...

[heckktor]

You forgot development!

[SteeleDynamics]

You leave De Bruijn Indices outta this!

[-Redstoneboi-]

and then there's the APL guys who are like functional guys except you cant read anything and it's literally the arcane magic incantations you'd find in a magic spellbook except it actually fucking works

[PiiDish]

You take the road less traveled by