The purest coding style, where bugs are near impossible

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Functional programming is a powerful paradigm in the programming world, where strict rules are applied in order to reduce bugs to a point where they are almost impossible to write (in many common cases).
It doesn't come without some difficulties though, and so this video aims to explain very simply, the concepts that underline the two main functional paradigms:
- (Normal) Functional - the paradigm we can borrow techniques from in many non-functional languages.
- Purely Functional - the paradigm that applies all the rules strictly, in order to be as bug free as possible, and the paradigm that covers most functional languages.
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0:00 A functional welcome
0:33 Coderized intro
0:40 The imperative and declarative paradigms
1:32 The functional paradigm
1:50 First-class functions
2:07 Closures
2:42 Closures example
3:40 Using functional
3:45 Higher order functions
4:07 Immutability (and side-effects)
4:43 Currying and objects with closures
6:07 The purely functional paradigm
6:42 Evaluation vs execution
6:55 Strict immutability
7:06 Monads
7:23 Using what we can
7:38 Benefits and drawbacks
8:21 Keeping an open-mind
8:40 RUNME (Sponsor)
9:46 End credits

[@savege-l2737]

The animation is amazing

[@NotHumanPerson]

So true

[@revimfadli4666]

IKR? The Doodley of programming. Even the chill voice is similar

[@vaisakhkm783]

Which software are you using Transitions look awesome 😍

[@MandosaWright]

Damn, I love the Buster Sword with materia 😂

[@CoClock]

Simply amazing

[@petrie911]

Bugs are nearly impossible? You underestimate my power.

[@asdfghyter]

i think one of the largest benefits of pure functional programming is that the referential transparency allows you to use equational reasoning on your code to _easily_ see which programs are equivalent, which makes refactoring almost trivial. it’s a lot less stressful to know that you can move things around however much you want without worrying about anything changing behind your back

[@darrennew8211]

In contrast, when you want to refactor things, you might wind up having to change a whole bunch of things that are unrelated to the actual change, especially if your domain isn't something you could consider functional. Imagine a highly complex set of calculations about some business you're supporting, and now Marketing wants you to (say) change how long customer responses take way down at the bottom of the stack depending on how much money the customer spent last month. Now you have to pass that data through every level down to the bottom where you need it, and in every place you call that bottom function of deciding how long something will take. The alternative is to pass around an entire blob of everything about the customer, just in case you need some of it for a specific calculation somewhere, at which point you still have to find all references to it as well as handle returning new values back up the stack when you change it. Doing a functional approach to an OO problem makes refactoring as hard as doing a simulating an OO approach in the middle of functional code.

[@asdfghyter]

@@darrennew8211 it is sufficient to have a single data type that you pass around, you don’t need to populate it with everything you might possibly need, since adding more things to it only requires changing the place its constructed and the type definition. if you really need it to be globally changed immediately from deep in a branch (it’s probably a design issue but) you can always just put in a mutable reference for that specific value (and thus breaking purity). yes, it’s an annoying refactor to make, but it’s mechanical and you can just follow what the compiler tells you and be confident that it’s still working as expected this is not an issue i encounter regularly though, what is the context where you have ran into it when writing FP code? if you use the standard pattern of Elm code for example, what you’re mentioning is a complete non-issue, since there all state goes through a global function and you can just add the extra state you need at the appropriate location and it will be propagated along as needed by the code you have already written

[@darrennew8211]

@@asdfghyter I think adding all widely-distributed state to a global structure for an entire multi-million-loc program would probably be problematic without better support. I've never had the pleasure of working on a megaline program in a purely functional language, but my brain has problems dealing with pure functional once it gets above about five thousand lines. It sounds like you're basically saying "pass a pointer to the entire memory of the program around, and you can fix the problems with functional programming." :-)

[@asdfghyter]

​@@darrennew8211 the idea of elm-style loop is that you have a tree structure with state that is relevant to different parts of the program, then when you enter a part of the program, you extract that part. you can also have some data that is relevant to all of the program. in order to change components of the state that is not yours, you return a message that tells the main loop to update that data. another solution that introduces some more impurity is to use erlang-style message passing between components. that way each component is still internally pure, but they can send messages to each other and get mutable state that way. Anyways, the thing you are describing sounds to me like it would be a problem even in OO languages, since you still need some way to have a reference to some way to find the data you need. How would you solve it in an OO-way? It's probably possible to solve it in a similar way for FP programs.

[@darrennew8211]

@@pcap8810 My point is that if you have a routine that you suddenly need to have access to something to calculate a result that you never needed access to before, you might have to find all the places you call that thing and pass the new required information down the stack. Doubly-sucks if you suddenly need something like access to a database in a function you call from lots of places. That was always my problem with FP - you wind up with one seemingly simple change ("account for X in the calculation for Y") that requires changing dozens of places in the code. Using FP where OOP or procedural (or ECS or whatever) is more appropriate leads to those kinds of problems, IME. I'll grant that I haven't had a whole lot of experience in that, nor have I worked with people who have had a whole lot of experience in that.

[@coderized]

Functional programming is a powerful paradigm in the programming world, where strict rules are applied in order to reduce bugs to a point where, in many common cases, they are almost impossible to write. It doesn't come without some difficulties though, and so this video aims to explain very simply, the concepts that underline the two main functional paradigms.

[@sherlockmaverick]

Yeah, it stopped playing midway for me, haha! Thanks for everything you're doing, I'm learning a lot from your work!

[@hiteshjoshi2736]

Pin this comment xD

[@ProBarokis]

I was hoping that you will explain monads in this version. Was disappointed. Well... maybe it's too hard to explain them in one short segment.

[@Citrus_-ff7qf]

it's completely worth watching the video over and over cus it's that good

[@coderized]

@@ProBarokis Monads would need their own video I think

[@arthasmenethil5748]

3blues1brown meets fireship. Amazing animation that clearly communicates your message. I wish you made courses ESPECIALLY low level courses. You would be an awesome teacher

[@legendariersgaming]

Also reminds me a bit of scruffy

[@yaroslavkolyada6914]

Wow this describes my perception of this video so well. Amazing content!

[@shakerlakes]

Both 3blues1brown and fireship are excellent teachers and presenters. Fireship is like a human google AI summary of relevant subjects. How that guy is able to digest so many subjects is amazing.

[@mepipe7705]

But in the fireship that I know there is much more sarcasm

[@natecaine7473]

Sorry, I can't agree. 3blue1brown's animations graphically illustrate complex relationships and make seemingly invisible patterns comprehensible. (Even if Grant does use those "Pi" characters; they are stand-ins for *us* . They are confused or perplexed by or questioning things that *we* should be confused by....and that Grant is about to explain.) I didn't get any of that from Coderized's "coding style" video. I don't know much about this topic and I didn't come away having learned anything. This is more a *review* video for those that already *know* these styles and differences, and might need a refresher, or see them brought together in one place. So maybe it succeeds at that. I would prefer some actual code examples shown side-by-side that illustrate how each approach (or language) handles an important feature, and then the examples dissected to show the pros and cons of each approach. (Other commenters made this same point, and there *are* videos out there that do just that.) Instead (and this is all too common) the animations here are little more than "eye-candy" to fill the screen during the narration. At times you could close your eyes and not miss anything, because this is no real information on the screen. At about 1:50 he does show something technical, and I had my hopes up. But then it's soon back to cutesy and meaningless animations that contribute nothing as he confusingly discussed closures. (And the proof of that is that he later went back and re-edit the video with additional material to try and fill in the gaps.) With Grant's videos (3Blue1brown), I almost always want to know more about the topic, and am inspired to seek further. Often I am so captivated that I wind up binge watching more of his videos. Here, with Coderized, I feel cheated that the video is over and I didn't learn anything. I *am* inspired to learn more about this topic, just not via this channel.

[@superblaubeere27]

Ok, I still miss the part where he tells us why he thinks that functional makes bugs near impossible

[@amazeinggames]

Well, every paradigm can have good or bad code; you can never have a *bugless* paradigm or bugless language (the bug is created by the user, afterall). The title is just meant to be sensational

[@KevinArellano]

As long as you code in dark mode, it wont attract any bugs.

[@powertomato]

Short version: Because if the entire code is stateless and immutable, then the entire code can be represented by mathematical functions which then can be used to compare against the specs and to even automatically prove properties. Long version: Say you have to implement a traffic light, and need to prove that at under no circumstance, two perpendicular lights will both signal a green light. In imperative programming QA and testing are the state of the art approach. But those are probabilistic: unless you have a testcase for each and every possible input, for each and every possible program state, tests are only evidence but never a full proof. Even if you just have two 64bit input variables, that means having 2^128 (~3.4e38) testcases for a full proof. This problem is known as "state space explosion". In order to reduce it you need to involve semantics definitions of the programming language and because of side effects those can get pretty nasty pretty fast. In functional programming you can just prove each function individually, since there are no side effects. So all you need to do is show that the traffic-light output function is not capable of showing green lights for two perpendicular lights for a range of inputs. Then you show the arguments are indeed in that range, by showing the previous function's output is in that range. Rinse and repeat until you're left with constants and user input. It's just so counter-intuitive to think functional. In the famous cooking recipe analogy to an algorithm, it would be as describing cooked spaghetti as a series of transformations on raw noodles and water: Functional: cook_spaghetti( spaghetti, add_salt( boil(water) ) ) Imperative: 1. take water 2. boil water 3. add salt 4. add spaghetti 5. cook spaghetti IMO the imperative list of commands is just so quick to write and cheap to develop that it's hard to justify higher development cost. Unless you're sending stuff to space or write safety critical software, tests will do just fine and will be much cheaper. However there are some uses outside that space: when you're dealing with lots of concurrent events, handling everything in imperative event handlers is a nightmare to maintain. Observables ala Reactive UI have been a godsend in that regard.

[@oscarfriberg7661]

@@powertomato It’s not really about proving that the programs are correct. No one got the time to write formal proofs. It’s just that stateless programs are in general easier to reason about. You don’t have to worry about which order you call X() and Y(). If you can call both, then both are safe to use. When programming with states there’s a risk calling Y() before X() cause trouble, because the programmer didn’t consider this possibility. Suddenly you need to reason about which order things are done. But this is just one type of bug. Stateless programs are still subject to other types of bugs.

[@sufilevy]

I never thought I would say this about a programming video, but this video is just... beautiful.

[@coderized]

Appreciated 💜

[@RobloxPrompt]

I think this is very interesting. Cause while making an adder you try your best to derive logic from binary inputs such as 0b1 for example then 0b10. You want to combine those inputs in an and gate to get 0b11 for individual bits. So then you start creating an equation to explain what each logic gate could be doing. And you can use that example as 0b1+0b1==0b10 or 0b1 and 0b1 == 0b10. With xor gates you simply have the even numbers and 0 and you can think of it as a Table or index in which the bits have to equate to. Which is why you create if and then functions. Making it a more declarative type of mathematical language. Just it uses symbols for the if and then functions. Which means you could also do ⟹ [{|0b1|}] to represent then true. Meaning if the function is true then it outputs 0b1. It also uses lim(n) as a function since setting the limit would be important for 8 bit input counters or adders. Think of it as similar to boolean algebra but with if and then statements and a limit function to have a limit bit integer. It's also structured so that the bit's are represented clearly and so that only with the prefix 0b it can indicate as binary. Anything with |n| would mean the exact value of n. n multiplied by 1 being defined as 1 or 0. or {|n(1)|} := {|1|,|0|}. Since it would be multiplied by a factor of 1. But if multiplied by a factor of 2 and so on then its {(|0b10| ∨ |2|), (|0b1| ∨ |1|), (|0b0| ∨ |0|)} Which would be (n+n'...). Why n+n' Well simply because that signifies the addition between the two binary numbers. And you use if functions to basically check if n equals a certain number whether its decimal or binary and then if the number equals each individual number of a table then the result should be true. This would work for both xor and xnor. But if you want to do xor then just do n%2=={}

[@ZILtoid1991]

Here's the best part about programming paradigms: Unless you're in a really bad enterprise situation where you're forced to use only one, then you can mix and match them. Functional programming is pretty useful, but there are times, when the side effects are needed, such as in game development, digital signal processing, etc. D supports multiple programming paradigms, and thus that's my main preferred programming language.

[@coderized]

I 💜 multi-paradigm languages. Always nice to be able to use the right tool for the job

[@ericpmoss]

Yes -- the same reason I like Common Lisp, give or take a few questionable macros that seem to be popular.

[@darrennew8211]

You sometimes lose a lot of the benefits of some paradigms by doing that, though. If you can return closures from methods inside objects that refer to instance variables, you lose some of the encapsulation. If you have a functional language where you can return a writable pointer to data, you lose the referential transparency. Stuff like that. Sort of like how an unsafe language lets you screw up *anyone's* code, not just yours.

[@concernedcitizen3254]

Agreed this discussion is basically irrelevant in 2023, use classes and functions where appropriate and stop trying to be fashionable.

[@ontheruntonowhere]

@@concernedcitizen3254 It's not about being fashionable. It's about understanding that the current state of the art is far from its pinnacle and we're slouching iteratively towards Bethlehem with each paradigm shift. We've been coding for maybe 100 years...where will we be in 100 more? 1000? 10,000?

[@WarrenMarshallBiz]

"where bugs are near impossible" Challenge accepted.

[@macwas5900]

The animation is so clear, I love how it enhances your explanation. Thank you for this! Hoping to see more

[@chawker67]

I can't even imagine how much work you put into this video... It's so beautiful and smart it's a form of art at this point.

[@teeesen]

I loved the Room 101 joke. On another topic. We have a bad habit in computing to use the same word for different concepts. Often we use the same word for a static entity and a dynamic entity. And I think this can be very confusing to learners. Some example are “variable”, “scope”, and “function”. I’m thoroughly guilty of this myself, although I’m trying to do it less. When I try to teach this topic, I find it useful to distinguish between function definitions and function values. Closures are just function values. The idea that a single function definition can give rise to different function values at different times takes some time for programmers to understand when they first encounter it. Anyway, great video; please keep it up.

[@victor-ling]

I absolutely love how you expressed a con of functional programming as "Tricky for Imperative Programmers" ... this is perfect. I have been doing functional programming professionally for over a decade now. So many times I come across comparison videos that get this part confused and end up only saying that functional programming is "tricky" or "hard to read" ... but that is just their imperative bias coming through unchecked. We aren't born with the intuitive understanding of how a for loop works, we have to learn it ... and everyone learning programming learns it very early ... but we can't take for granted that learning still occurred. When people come across a map function your first instinct is that it's more confusing and harder to read than a simple for loop ... but this isn't a fundamental fact, it's just that you've been using a for loop for so much longer you just aren't used to using and seeing the map function. Once you are used to higher order functions like map, you may start to find them incredibly elegant (I do) and then start to prefer them. So thank you for getting this part right where so many other videos have failed!

[@coderized]

Thanks! This was really nice to read

[@samuraijosh1595]

bruh let's be real. most imperative programmers arent going to have that hard of a time figuring out how map works. functional code can get really function-nested or transformation-nested and thats what trips people off. if you want to design an optimised functional style model of something, you have to plan ahead of the right transformations your input data should go through to give you the desired output and mastering that isnt just a matter of lack of familiarity with functional paradigm. it's genuinely objectively harder for normies to wrap their head around.

[@DryBones111]

@@samuraijosh1595 That's because most people do a terrible job at domain modelling in their current paradigm too. Less of a functional programming problem, and more of a poor design problem.

[@epgui]

The hardest part about learning FP is unlearning the imperative paradigm. People confuse simplicity and familiarity all the time, and it significantly hinders progress.

[@amigalemming]

An excellent FORTRAN programmer is in every programming language an excellent ... FORTRAN programmer.

[@Rafael4]

Thank you for the dedication in keeping the videos with high quality!

[@execute214]

mmm.. video... 24/10 does anyone else feel deja vu?

[@coderized]

Yeah 😅 - I uploaded this a few days ago but took it down shortly after to fix some issues and add in some clearer explanations. It has quite a few changes since the last one!

[@HoloTheDrunk]

Ah yes, time for monthly self-gratifying medium-length video about a subject I already know about

[@melissaprice1424]

Perfectly clearly explained if you are talking to an audience who already knows the information. Totally useless to a beginner.

[@vaisakhkm783]

​@@melissaprice1424 it's best for people like me ... where i have written few haskel and ocaml by never learned much deep

[@kennyt1m403]

​@@melissaprice1424I could not say that it's totally useless since it introduced me to the different paradigms in one of the visuals as a beginner but I have to admit that most of the stuff goes in one ear and out to the other

[@Wilzzub0b]

I love these videos! The slow pace, beautiful animations and how you compare these really complex subjects to our everyday objects makes it so much more clear to me!

[@yewo.m]

5:17 - Fun fact, before JavaScript classes were introduced, people just used functions as classes or object constructors. The function would return a plain object, onto which you would assign functions which you wanted to be the object's methods. Any data or "methods" which you wanted to simulate as private properties and methods would not be returned on the plain object but simply created inside the scope of the function

[@wileysneak]

although this was/is a valid pattern, it may be important to note that js has always been based on the prototype model, classes are mostly sugar around the same proto model. e.g. rather than write a function that statically returns new closures (costing memory because scope), you'd write a prototype object then construct that instead. search 'prototype mdn' for more info

[@darrennew8211]

That's called "Prototype OOP".

[@BlazingMagpie]

@@darrennew8211 Creating objects in closure isn't prototype OOP. Prototype OOP is attaching another actual object to search for properties in if they don't exist in initial object.

[@darrennew8211]

@@BlazingMagpie That's prototype inheritance. But sure, it can get kind of fuzzy around the edges, given the number of different ways to do encapsulation, instantiation, and inheritance.

[@CyCloNeReactorCore]

i kinda still do this

[@AllanSavolainen]

Recursion is a breeding ground for bugs

[@sdjhgfkshfswdfhskljh3360]

Finally, unbiased review. I'm tired of people believing that I *must* use functional languages.

[@DomainObject]

No one is saying you *must*. But you definitely *should*.

[@maskettaman1488]

No one with a job is telling you to use functional languages

[@bluedark7724]

Functional has its uses, a pure functional program doesn't do anything, as everything that matters to humans needs side effects. Coding languages support or do not support functional paradigms. C# is focused on OOP, where Rust is more focused on other styles.

[@TimothyWhiteheadzm]

In my experience pure functions are not significantly more bug free. Most bugs I experience are: 1. incorrect interpretation of requirements 2. careless coding 3. issues with data being passed from one part of the program to another or one system to another. 4. UI related unexpected behavior. 5. a misunderstanding of the language/framework being used. In the code, whether the function is 'pure' or takes in mutable arguments has very little effect on how many bugs may occur in that function and pure functions may in some instance be much harder to work with and understand thus creating more bugs which is why most of us do not particularly try to use pure functions even when it is possible to do so. Functional programming can have an edge when you do full unit testing and need highly reliable software where each function is analyzed for correctness but that type of code is actually quite rare in the real world.

[@darrennew8211]

It tends to work best when your problem domain is function. Something like a SQL interpreter (where the results are committed at the end) or a compiler or a sorting algorithm or something like that. If you're doing something intrinsically mutable (game engine) it's much less feasible and helpful, because as you say most of the errors made by people experienced enough to be using functional programming are logic errors.

[@darrennew8211]

@@aaronfleisher4694 I disagree that logic bugs are always careless coding. Sometimes they're just mistakes. Sometimes they're just situations your users tried that you didn't think of and break your code.

[@darrennew8211]

@@user-tx4wj7qk4t I disagree with your list of common bugs. Those are "common bugs that are pretty trivial to find the cause for." IME, any time the code base gets bigger than one person can keep in their head, the most common errors are 1) logic errors, 2) people who didn't know the requirements (whether coders or customers), 3) misunderstanding how libraries or frameworks you rely on work. 90% of what you say is right, but it's specific to a certain kind of program and a certain size of program.

[@TimothyWhiteheadzm]

@@user-tx4wj7qk4t I think you are generalizing too much. The software development space is large and the problems in on type of development are vastly different from those in another type of development. The issues in an OS project vs a website are vastly different. You mention null reference exceptions for example. When I code in Rust, I never ever get those because you can't. In JavaScript or Java it is certainly possible by in my experience relatively rare in Java and when it occurs in JavaScript it tends to be due to unexpected data entering the function not because of whether or not the parameters are mutable. I stand by my point that in my own line of work purely functional programming would not only be impossible but where it is possible it would make very little difference to the number of bugs I deal with because the vast majority of them have to do with issues of requirements, carelessness, communications between systems etc. We generally don't do unit testing for this reason because end to end testing is far more effective at picking up the bugs that actually occur. But in other types of development the experience will be very different. As mentioned I also have some work in Rust and the types of bugs are very different but still almost always intersystem or requirements related. Most of my Rust work however involves either new development or updating the code to handle updated dependencies. With Rust, my experience is that once it compiles it usually works and any changes will be due to new requirements not bugs.

[@darrennew8211]

@@user-tx4wj7qk4t Yes. It's entirely possible for something to be common but trivial. You know what's even more common and even more trivial, in exactly the same way? Misspelling a keyword, or leaving out a closing brace. Null reference exceptions are no longer a billion dollar mistake now that we have memory protection on computers. I disagree that the reduced cognitive load of FP would necessarily reduce the number of logical errors. A logical error is when you write code that you think is correct but it isn't. Making it easier to write correct code won't make you think the solution is better. I think people who are used to writing smaller simpler programs have a different idea of the distribution of bugs compared to someone writing large complex interacting long-lived systems.

[@rismosch]

Thinking functional programming doesn't lead to bugs is something a naive programmer with zero experience would claim. Programming languages like Rust may claim safe memory management, but it doesn't prevent you from making logical errors, for example doing the wrong mathematical operation or writing incorrect data to a file. And especially when you are working with other libraries (including std), you are working on trust that this library doesn't produce bugs. But I encurage you to simply go to the source repository of your library of choice and you will find an issue list which is filled to the brim.

[@gigachad8810]

1. Rust doesn't "claim" memory safety. 2. Some types of errors can indeed be solved by different (types of) languages. For example, data races are probably pretty rare in functional languages. 3. Std bugs are "relatively" rare and are mostly related to platform specific behaviour. For rust 0.7% of the issues on github affect std. But I do agree with the fact that a lot of bugs are logic related. Most important bugs are not though. (looking at you, 70% of chromiums high severity security bugs)

[@santherstat]

very beautifully made video. as a beginning programmer, I really appreciate the way you explain things

[@babylonsjukan]

I'm B L O W N by the animation, it is like watching art in its purest form while learning a ton. 👏

[@parablesboltnoel]

Care to share your secret... would love to make such illustrated videos for my students in class

[@snelbops]

Great animations, would love to know how too 😊

[@peteregbujie]

I believe he is using Adobe After Effects

[@malkitsingh01]

Appreciate the high quality work and the efforts that you have put in making this video ❤

[@christopherstage9814]

I really enjoying the pacing and visual representation of the functional programming concept in this presentation. Cheers to you for this approach in explaining it. I’ll have this as resource to use in my dev team’s ever evolving philosophical discussions on writing gud kode. 😄

[@ajayadav09]

this is amazing. Thank you for putting in the efforts to explain it visually.

[@ness20xx27]

This video is really great. The animations & explanations make it a real joy to watch. Your voice is very calm too, thank you for this great video, I'll definitely try and see if I can do some functional programming soon!!

[@raffimolero64]

there's a saying in the haskell community: "You should be able to figure out what a function does from just reading the function signature." half of the work is just the function signatures. a lot of the work is upfront so bugs in functional code are called "bad function signatures" and "type errors", both compile time concepts that never make it to production. -mostly because there are like 2 haskell users in production.- refactoring is guaranteed to be correct in the end, but you may have to churn through a whole chain of other function signatures if you forget to make something a monad, for example. i am *not* speaking from experience, just what i've heard around.

[@coderized]

Great comment!

[@mskiptr]

Sounds about right. Tho unless you go into theorem-proving territory, you will often have multiple possible functions for any given type. (still, most of them will be obviously incorrect, so it's definitely harder to mess up)

[@Rainfires]

I appreciate this very much! It’s a great way of thinking about the paradigm and how we should think while using it, but it does lead to some misconceptions about things like its performance and storage aspects. For the languages themselves, there’s some funky stuff that actually goes on underneath the abstraction layer we think on. The craziest example I have is how some languages don’t completely create new versions of data, but structure references in a way that enables very very fast equality checking for structures as nested as you want. So, some underlying data structures stuff ends up being faster than it’s non-functional brethren despite suggesting the intuition (coming from a procedural mindset) that it should be slower.

[@samuraijosh1595]

can you give an actualy example of this instead of making a vague point that tries to assuage the bad reputation functional style has in terms of its performance?

[@Rainfires]

@@samuraijosh1595 Gosh, sure! It’s going to be a struggle. A handful of functional programming talks do bring this up and mention it in passing, but it’s not the easiest to google search transcripts of KZbin videos. I’ll see what I can dig up from my memory and I hope I can satisfy your question. Typing out a response on my phone is tricky. One would be Richard Feldman’s talk “outperforming imperative with pure functional” describing some work he’s doing on a newer language. A handful of Clojure talks mention this when introducing the language as a core for how they perform equality checks. There’s one by Mohit Thatte called “What Lies Beneath - A Deep Dive Into Clojure’s Data Structures”. And, I could have sworn there’s a talk by David Nolan where he’s doing a beginner’s talk for CLJS where he mentions the data structures in passing. I’m sure there’s other examples, but, simply, (some) functional language designers do not simply slap immutable structure primatives into their languages without thought or the recognition that there are performance hurdles. There’s tricks that go on under the hood that are intentionally hidden or at least abstracted from thought while you utilize it with the general immutable paradigm!

[@minhquangpham]

Haven't finished the vid yet, but looking at the animation and the effort you put into the vid, you earned my sub ;)

[@Akhilesh.Gulati]

wow!!!! simply amazing in so many ways from explanation, to audio, graphics, style .... to the clarity in logic. i ♥it

[@dvikauglaumishrauca]

Beautifully explained funational programming basics through animation. Code samples and more on monads would be fun too.

[@th34lch3m1st]

Great content. If all programming courses were as focused on the main concepts as in these videos, without getting lost in details and syntax (ceremonies, as Venkat Subramaniam would call them), becoming a programmer would be a breeze. Instant subscription for me.

[@XnonXte]

I like really the animation, you could go a long way with these. Keep it up! You just earned another subscriber.

[@snk-js]

man you nail it on animation and communication altogether

[@SimGunther]

7:11 The infamous Monad was recognized in Homological Algebra after the original term "standard construction" was used for it, but before it was officially a "monad" in category theory back in 1967. The etymology of the original term "triad" gives a crucial hint for what the monad is. First, since every function should take in one and only one parameter and return one and only one value, we need a rule set that is surjective to map B -> C. Enter the context! This world context C has access to the value B and carries rules, such as lazy invocations of the runtime to write/read file content, if one wants to manipulate the context passed around from one function to another. Secondly, we must have an injective function mapping A -> B. Luckily, any pure function will do the trick, but if you wanted to, you could use a function that is monadic as well. The reason that division is monadic in nature is due to division by zero cannot a defined result; thus we say this case returns Nothing while everything else creates Just the divided value. We commonly say that the IO monad is a more specific form of the state monad because it has more specific rules about the kind of state we're manipulating and how it changes. It's not like we can represent Tree Monads as IO Monads since it'd be silly to have tree rules used to manipulate file sockets. But if we wanted to use the value in the Tree Monad in an IO Monad, one must implement a way to extract a value from the Tree Monad. This may not be guaranteed in every monad like the Maybe Monad, but it's something to think about when designing your own monads. That's why Monads are called "triples" or "triads" in category theory. Because it stands for the three components of this specific structure: the input, the output value, and the world containing rules to manipulate itself (thus why monads are endofunctors) and the output value itself. The more you know 🌈

[@coderized]

I learned a lot from this, thanks!

[@clamhammer2463]

So, I took the time to learn quaternions. Doesn't that exempt me from learning monads?

[@SimGunther]

@@clamhammer2463 While useful as a way to look at a 3D rotation in a 4D perspective, you were better off just learning 3D rotors as a Marc ten Bosch article explains. On the other hand, if you're in a code base already inundated in quaternions, you're good to go there. Might as well just learn linear types and effect systems if you only care to have effects from a straight forward perspective.

[@clamhammer2463]

@@SimGunther this was mostly a joke but I was required to learn it in order to encode the pitch/yaw/roll of a spaceshuttle to easily do the math with an easier data structure. After looking into monads and learning what they are and what they are for, I'll realistically never reach in that pocket of my toolbag again.

[@SimGunther]

@@clamhammer2463 Glad to hear about that experience with quarternions! Also, that impracticality and unwieldy nature of Monads beyond the super mathy world is exactly why I mentioned linear types and effect systems if that's the itch you need to scratch in a functional language.

[@Deathkyun]

Just started training at a company that primarily uses Scala, and it's actually been a pretty interesting experience getting a handle at a new style of programming.

[@Bobbobbob984]

Do you think there are actually less bugs?

[@Deathkyun]

@ashaw596 If you're using pure functions, the compiler detects a lot of the stuff for you that would otherwise get cought at runtime. So from my, albeit short, experience yeah it seems as advertised.

[@Deathkyun]

​@@user-tx4wj7qk4t Thankfully the company provided us with the latest edition of the book. Having to go through all of it and provide output in 3 weeks was quite the challenge, but we pulled through. We're getting engrossed with the frameworks that support it now.

[@archbox8593]

Awesome, I loved this overview :) nice visuals!

[@frittex]

The visuals and the explanations are AMAZING

[@Brootahlizer]

Your animations are excellent - which software do you use to make them?

[@tharunkanna1401]

Love the animation, great content. Expecting a lot more of computational theory from you.

[@bmansk8520]

I have been coding in javascript mostly and recently got into C# and typescript. Coming from javascript (specifically react) I was totally on board with functional coding. Then moving to TS and C# I found out about the wonder that is classes, and OO programming. Now I'm finding myself mixing the two, and this video was a awesome look at something I thought I already knew a lot about. I didn't even know there was a thing as "pure functions". Awesome quality, and I definitely learned something.

[@coderized]

Thanks man! Glad you enjoyed it. Yeah, to embrace a mix of the different paradigms is probably the best way to go! :)

[@thedofflin]

I finally understand what a closure is, I swear I've banged my head up against FP so many times because I couldn't get my head around closures. Thank you for your short, simple and clear explanation.

[@hiteshjoshi2736]

For some reason i remember watching this same video few days ago and yet it was uploaded 30 mins ago

[@bonk2935]

He re-uploaded it

[@coderized]

I took the original down shortly after to fix some issues and add in some clearer examples - hopefully it's better explained now.

[@CrazyAssDrumma]

This is a great intro, I'd love for you to dive deeper and show some real world problems being solved by using oop vs functional, or imperative vs declarative etc :D Bonus points for comparing how to test each paradigm e.g. mocking nested functions etc in each paradigm

[@Nico-qq7xl]

Thank you for doing this type of videos. Love it ❤

[@alexkrauchi9535]

Really glad I found this channel. Such quality content and very well explained

[@kirkkork]

How is this animation so good!? Damn good job.

[@SensSword]

Absolutely amazing animation. Well done.

[@nicolo.lazzaro]

Thank you for the beautiful content. The world needs more of this!

[@thepisewigeon]

your video titled "Never install locally" forever changed the way I work. Thank you for making these. And also, I like your voice very much :))

[@coderized]

Really nice to hear, thank you!

[@ItsMingee]

Wow, great video! I left a comment on your other video and it's impressive to see how fast you iterated on it. Thanks so much for the work you do. My feedback on this is that since functional is a difficult topic that handles a lot of abstract ideas (with some abstractions on top of the abstractions), even if the explanation is logical and concise it doesn't necessarily reduce the difficulty in understanding it. One still has to keep a lot of these abstract concepts in their head. This was amplified since the video touched on many various topics (memoization, declarative/imperative, side effect, closure, etc.) in a relatively short video. The animations you used were beautiful and I loved to look at them. But in a lot of ways they didn't actually help me understand the topic any better, even in cases where they were used to represent abstract ideas. Contrast this with 3B1B (I know that's a high bar haha) where most of the animations he uses actually enhances the viewer's understanding of the topic at hand (and then is a little cute in the down time). Take 5:48 for example. While the diamond represents the abstraction of an expensive operation, the content doesn't actually visually represent that efficiency (i.e. processing an expensive operation multiple times) which forces you to hold that in your head kind of abstractly as you process the rest of the video. Another example is in the filter/sort/map around the 4:00 mark. The animations are beautiful and they do make sense. But more so if you already know what they do! The subtlety, speed, and singular nature of those animations make it less useful to someone who isn't already familiar with the topic at hand. Again this is all because I love the content that you make and I will continue to watch regardless haha. So it's not critical, just my two cents. Thank you for making content!

[@liam_iam]

I think this is good feedback. I liked the visuals and tone but it unfortunately didn't help me take away any insight that I can apply to my own work. Maybe that's unfair as it might not have been the intention of the video. But I really would have liked to see the same concepts covered through a more problem-based learning approach. "Here's a scenario where non-functional code is problematic, and here's how you can apply these functional concepts to write better code". Great work though, just can be pushed further imo :)

[@John-ul6rt]

This was a really good watch, thanks!

[@dontthrow6064]

7:10 - for a moment I thought, what could be so wrong. Then I heard monads and started crying uncontrollably. My friend asked me what's wrong, when I told him "monads", he started crying too.

[@NoahNobody]

What the heck! Those neat animations really combined with those succinct explanations really helped me understand concepts I've had trouble understanding.

[@Outfrost]

No actual mention of how, supposedly, "bugs are near impossible", because of course that's not true, and not even a characteristic of the functional paradigm.

[@prof_glue]

It's definitely for the youtube algorithm/to get more attention. Apparently the original video title was "what the func()"

[@alaacherif2165]

Idk how you're not at 1 mil subs yet but you deserve it

[@liledg2357]

Absolutely love the visuals and explanations, thanks a lot for these videos!

[@lasindunuwanga5292]

I think u have put a great effort in creating the animations. It is a great work and the explanations using these graphics are also very clear. Thanks ❤

[@LunizIsGlacey]

What did you use to animate this? It's so beautiful and clear!

[@ivandrofly]

Top animation... I've just been learning functional programming for a month, and this information is gold

[@jannsander]

Wow, your animations are top notch wich makes is dangerously convenient to ignore the awesome script and just get carried away by your really nice presentation stile... I watched the video twice, now i got it

[@TinusBruins]

A closure is just an instance of an anonymous class with a single method wrapped in syntactic sugar

[@sanscipher9166]

Can't have bugs if your code doesn't do anything :)

[@DevR00ts]

As always, lovely video. Well explained, and exactly what I was looking for. Thank you!

[@atharvsankpal]

Nice Video, amazing visualization

[@naman_dw]

Which software do you use to create these amazing animations?

[@WillEhrendreich]

This is absolutely the highest quality high level explanation of this stuff. Bravo. Absurdly good video.

[@be_cracked8212]

You have really outdone yourself with the animations on this one

[@sloan00]

Your videos almost look like digital art. Great job.

[@wety789]

That monad joke was amazing 😂. Great video and great animation, looking forward to more videos from you in the future!

[@Daniel_Zhu_a6f]

nah, it's tired. monad is just an interface of 3 functions. the real torture is haskell syntax.

[@Sebastian-hg3xc]

It actually harms the video because it brings up an irrelevant concept that most viewers won't know about and thereby get confused by why it's brought up in the first place.

[@ChiragAgg5k]

Those animations smooth af. Glad i found this channel

[@oskarpyke3488]

Fantastic animations, well done!

[@torarinvik4920]

Good video, but OO is neither Imperative or Declarative. Procedural is opposite of OO, and Imperative is opposite of declarative. So a language can be both pure OO and pure FP at the same time. For this to happen functions and all other values needs to be objects, objects need to be immutable, and there can be no side-effects. Inheritance doesn't break the FP purity either. I know of no such language to date though.

[@ChannelName991]

well detailed and informational doc

[@blacklistnr1]

functional style + closures: smart, simple, useful 100% purity + monads: a mathematician's fever dream

[@DocSineBell]

I just love how resilient is FP code to bugs. I'm trying to use it in the core parts of my codes because you know you can really trust for them to just work. I also love its strong modular nature. It makes so easy to change the code behavior.

[@lucaspinto9114]

This might be the most didactic and beautiful video about programming that I ever saw. I am a med student but I want so much to learning coding! Thank you for this wonderful work!❤

[@dilian08]

While the animation is great, it needs more coding examples. The previous and this videos are a bit too abstract to not have examples. For example, how a closure would actually be passed into other functions. Or even a comparison of code written in OOP and functional programming

[@coderized]

That's not really the goal of this channel. I'll do simple code comparisons and high level concepts but there are other channels and resources for more detailed learning. I can only cover so much and the point is to give people a basic understanding, enough to want to learn more on their own.

[@milankovacs4259]

Great video! Loved the ending

[@mskiptr]

This is such a nice overview! Even though I'm already quite used to pure FP, this video has definitely gave me a better understanding of closures. With Haskell or Idris they are merely an implementation detail (like the garbage collector) so we don't think about them basically ever. Building objects out of the was always a bit mysterious - until today And here's the best one-line explanation of pure FP: _Let's get rid of time! If it's useful, we can model it explicitly._

[@AidenElliott-ff2vt]

My personal favourite is OOP. The flexibilty, the encapsulation, it all fits together so perfectly. Each to their own, obviously, but in my mind, OOP just works.

[@EdouardTavinor]

well, until you add concurrency. then oop would work fine, if every object was in its own light-weight thread and communicated through message passing. unfortunately i'm not aware of an oo language that works this way.

[@ThatGuyFromThere1]

03:37 "or woman's" - Bro didn't want to get cancelled Btw, nice animations and amazing explanation!

[@mindget]

Really thoughtfully and beautifully made video.

[@xwtek3505]

It's actually rather easy to make bugs in even pure functional program. There is a paradigm where bugs are nearly impossible, though. It's the dependently typed paradigm, which is a subset of pure functional paradigm. In a nutshell, a dependently typed language allows a function to return a value of different type depending on the input *value* (not type, that's just generics), and the type is enforced at compile time. This is very useful because you can now encode proof and contract that ensures that the program works as intended. Essentially a statically typed contract oriented programming that you can reason about manually

[@fugduhhh]

Didn't watch it yet but looks interesting

[@JulianSloman]

Well animated, but not very informative, somehow... I guess it's targeted at complete beginners, so perhaps it would have been informative to me in the past. -- Would like a refresher on Monads though once you get around to it - but feel like at least explaining how side effects are handled in pure programming would have been sensible.

[@maurolimaok]

This FORMAT is very nice! Hope this channel grows a lot.

[@dreamingacacia]

It's funny when an amatuer like me which only understood the basic algorithms and basic OOP ended up with the functional paradigm without knowing what's better for performances. It's just the ease of management and readable codes that drew me in. If I understand correctly the ground rules would be 1.dynamic variables must take from input 2.private variables in functions must be constant. So you could say good bye to nearly all the bugs in the world. Though I already used these rules from the get go, since I never study something fabulous that people like to use. Btw I called the functional paradigm as modular programming, it's because I'm self-taught and came up with it by working experiences.

[@baksonyan4ik]

uooooghhh seeeeggs, another dose of very understandable and good information

[@locker47]

You should have kept the original upload up, then made a new video with just the edits. That would make it the best example of an immutable data structure :)

[@coderized]

I love this idea so much 😂

[@salzlord]

This is what I love to do. Sometimes when I’m bored and have nothing else to do I download some github stuff and just improve it as much as I can. This can be really simple stuff or really hard stuff (which tbh I mostly give up on)

[@TechJolt3d]

I love the animation style soo much. I wish I could animate like that.

[@min11benja]

I love the animations, do you use after effects?

[@coderized]

Yup

[@cayde-6976]

my parent says I'm a very special function

[@2dboys230]

Haha

[@piti118]

The animation is so good. Could you tell us what you use to create this animation?

[@adenzu]

it was a breath watching a video with a peaceful voice and no music in the background

[@Axacqk]

"Forces us", "guides us", sorry nope. Computers are supposed to serve me, not the other way round.

[@notanenglishperson9865]

Assist, not serve. Guiding is a part of assistance

[@feyntmistral1110]

What I've never gotten is why people seem to think that functional programming is in some way incompatible with object oriented programming. Classes with functional code are just as powerful and still offer you the ability to group related data under one object. It's like people think that just because you're using objects, every method in an object must only reference objects and thus be non-deterministic with lots of referential checking to ensure you're not doing null operations. No, you make member variables inaccessible from the outside, wrap them in accessor functions, and you've got functions you can pass to other functions now. Do your null checking in the accessors and you've got the simplest functions you can write so you know they're bug free, but just in case you can very easily write tests for every function of a class.