Python vs Swift | Chris Lattner and Lex Fridman 

I love that you interrupt the conversation to clarify on statements your guests make. Many of the times the viewer is wondering the same thing.

coming soon to python: from pyswift import *

love how Chris gets into the details of how value semantics is achieved in a thoughtful and novel way compared to purely functional languages or Java using string immutability. Copy on write has been around for decades of course, but Swift brings it up the stack considerably.

Love seeing this pure CS stuff. Please include more pure CS! So interesting. Would be awesome to see people involved in Rust.

When I learned C and Pascal, the first thing that I liked is that you can pass practically anything by either value or reference to anything else.

Swift really is an elegant language, its taking everything we've learned in the last 30+ years of programming languages and starting on a clean slate.

Excellent clip Lex, thanks for posting, much appreciated. Your channel is one of the best in the world. Thanks for interviewing remarkable brilliant guests and sharing them with the world. A+

C# knows both value and reference types and has an implicit operation called (un)boxing to switch between value and reference type when needed.

Really reminds me of the Borrow Checker of the language Rust.

what happens in swift if there is a reference to a string that you are asking to append to? does it then create a copy to that string?

You don't have to copy lists in functional languages. Generally speaking of you add something to a list in FP, you create list that points to the old one and your new value. Typically they are implemented as a tree to achieve this

I like to listen to Chris cause the way he explain things is fairly easy to understand

Ooo. I love both of these languages. Thanks for doing a comparison!

Great video! Could a whiteboard or blackboard aid communication and discussion?

Man I can’t tell you the number of times I’ve gotten stuck by that reference semantic thing with Python. It is super annoying and very confusing especially when you’re using someone else’s Library. Thank you for mentioning that.

Increíble podcast, gracias.

Lex's face change when Chris says "copy on write" and the question that was piling up in his head is answered. :)

Swift sounds great, but if I understood everything correctly something to some degree similar is done in Rust. There is no copy on write, if you own a string you can just manipulate it. But once you give out a borrow you can't manipulate it anymore. And the receiver can't store away a reference that can change, but if you pass ownership to someone else that one can of course store and change it, if they want to. So you get pretty much the same advantages as with Swift, but you don't need any runtime checks (as you would need with copy on write - there you need to check if you need to make a copy on every write operation). You can do some of that with C++ (e.g. Qt's QString is copy on write internally), but it doesn't track ownership the way Rust does.

This is functional programming pilled

In my humble oppinion, C++ does this the best since value semantics is default, reference semantics is opt-in. Furthermore, you can pass by constant reference to provide a read-only view over the data without copying. Then, there is move semantics which is required if you want to make value semantics efficient.

awesome, thanks

I don't understand why programmers have a hard time choosing between or understanding reference and value semantics. Do you want that object to exist on its own or not?

From my experience, Swift has both value and reference semantics, value for `struct` and reference for `class`? Am I wrong or is Chris talking about non-custom data types?

That cauliflower ear is getting noticable

So basically Swift neither passes by value, nor passes by reference; it passes by proxy. The proxy is smart enough to keep track of who should get the new value and who should get the old value when mutation occurs. Is this correct?

Chris Lattner has the mannerisms to be one of those Thermian aliens from the movie Galaxy Quest.

Good Design!!!

If the tensors (and other objects in general) are being passed by value and cloned in Swift, isn't that inefficient? That's the whole point of using references for objects, arrays, maps, etc. is it not?

PHP arrays also do copy on write.

Java maintains String objects as immutable, but they use String objects pool to reduce consumption of Heap memory while runtime. So the concern guest is saying is very minimal in real world performance and memory consumption.

Thanks Lex, thanks Chris :) .

"Good design is something you can feel" That's called subjectivity lll

"Actually good design is something you can feel" totally agreed. I bought a google phone and miss apple design

Thank you Lex... Also thank you for calling out the BS indirectly!! As an engineer they're pretty much like politicians because we're not allowed to say no, just that things could theoretically happen.

Such a nice bloke

I’m a mechanical engineering student just getting introduced to programming languages Like matlab, python, and I think C or something used for arduino. Swift sounds interesting; should I get familiar with for my field or should I focus on what I’m learning rn?

Very interesting

Python and java is all you need to manifest a Lamborghini

I remember this dude from Galaxy Quest.

Was just wondering how swift handles this and RU-vid algo came up with this video. I didn’t know the exact terms to search for lol

Should try to get Rich Hickey on the show!

So when are we getting swiftpy

Whenever I hear about these fancy features of some fancy language, I think: matlab can do that..

Started Swift about 2 years, it almost immediately became my favourite language. Going from Swift to Dart felt like such a downgrade.

Both Swift and F# have value semantics, unlike languages such as C# and Java. He's wrong in saying that immutability means lots of copying. That's not how immutability is implemented in most functional programming languages. His description of what Swift does to implement value semantics is essentially what most functional programming languages do to to get efficient immutability and value semantics. For instance immutable lists and maps in F# are NOT copied when passed as parameters to other functions. Same goes for other data structures.

Isn't this the same idea as pass by value or pass by reference in C? I think thsts what im hearing explained here. Do you pass the memory address of what you give to a function or a copy with the same value. Its hard to wrap your head around sometimes because you can pass a variable to a function in C, increment it, but the original variable has not changed because C is a pass by value default language. If you want the function to modify the original variable you pass a pointer to the variable. The pointer is then passed by value and now you have access to the original variable inside the function. I think this is the concept hes talking about.

Not particularly a fan of python...but also not convinced by functionality of swift....it certainly is elegant...very clear...as language.....So if u can get things done by using one set of tools...why do u switch to new tools...for doing same task...unless....there is huge performance difference...or some added abilities....

also 3:59 if people are doing work and havent learned about value/ reference types or pointers which is day 1 programming 101 basic stuff then they should probably not be.

Thumbs up for value semantics

One should consider making a compiler for python; which will compile python code (obviously optimized) to Machine Language to speed it up...

I prefer python for its both pass by value and reference. For the game I’m making in python, I use the fact that I can have multiple pointers to objects to help pass values dynamically between classes without global variables.

Chris is ever the indefatigable pragmatist!

Wow, this is a smart programmer who talks sense.

8:05 is he talking about Singletons?

Five seconds in, “pythons not great at building libraries because C” 😂😂😂

For someone curious about defining these in Swift: define the thing as a ‘struct’ to get value semantics, and a ‘class’ for reference semantics.

I am superrr new to programming. Are they talking about "pass by reference" vs "pass by value" ?

Chris is so likeable and although I mostly agree with him so that might be bias.

Swift Rocks

Who is choosing Swift for things that they'd choose Python + C for if Swift didn't exist?

Swift fan boy here

The thing that really annoys me about Python is that you can't really compile it.

Has swift gone out of the Apple ecosystem yet? I think the real problem for swift adoption outside of Apple is their priorities

2:50 i know exactly what they r talking about.

I love swift

Just use const. Value semantics are inefficient

hat kirkirii 🔥🔥

Swift vs Julia?

I start programming in swift not because is good language, only because i want to make something in iOS and MacOS, but __there nothing like C and C++__

Clojure is another language with value semantics.

4:10 Enter Rust

Not sure there’s much difference really. You need to decide in both languages whether you’re using value/reference semantics. In python this is just done his clone().

This is why "learning to code" is not meant to be taken literally. You should learn how to bypass having to use code as much as possible hahah

Love Swift!

Coming from a C and Linux background, Python feels like a natural evolution. Swift feels weird, kind of like JS does.

Scala

Looks like a young Bill Belichick

I know it's his baby but does he know what Apple is actually doing with/to it? Let's put to bed the idea that anyone outside of iOS is actually using it seriously, that's a non-starter. In the iOS environment, it's turning into a monstrosity with a new paradigm introduced every other week, MVC, MVVM, SwiftUI. There is no sign that Swift can or will outgrow the very limited iOS ecosystem and even that will be cannibalised by Flutter as a reaction to the overstuffed verbosity of the other mobile languages. It's also strange that in the same train of thought that he suggests C has to do the heavy lifting for Python, he goes on a big tear about the need to pass by value. One of the major reasons everyone always ultimately reverts back to C/C++ for performance is the ability to engineer efficient memory use and speed through proper management of references, specifically opposite of the paradigm Swift is pushing. Jeremy Howard was on a little while ago namedropping Swift as a poor language for computation which is why he was sticking with Python. Even in iOS, most of the heavy lifting is still managed at the C/assembly layer.

Python is kids language.

Hey Lex, new programmer here. One mistake I can easily point out in this conversation is you both have an Aquafina water. Please fix in the next update

Two words: Functional Programming ;)

The entire language performance discussion is in reference to current CPU technology but if Intel manages to perfect quantum processors and someone like Microsoft manages to build home computers out of it, will performance still be of any concern at all? Wouldn't it make sense for all programmers to build on C and Python rather then learning 10 different languages for different applications in the market?

Go is the best;)))

Didn’t realise graham stephan knew so much about programming

#Lex is a drug, I am getting addicted bro👍

“Actually good design is something we can feel”. And that’s why Steve Jobs was right since the beginning and Apple is most valuable. Developer experience is of most importance. When it feels good, you build better products.

Lex's IQ is so high, love watching this guy

Andrew Madsen is the Swift God.

This is basically a really good example of why Rust is good....

Total beginner here. Former Art Student. Craving rules and objectivity. Angry at subjectivity. Starting my coding journey, upon recommendation from a friend, with Swift Playgrounds. Pretty much everything in this video going over my head 🤷‍♂️

Julia may be a better choice!!

Coolness, Apple I think should be the one so the best is Swift coz' they will support it and Apple product is the future (also Tesla if Elon makes smartphones and computers). God bles..

Julia is better for ML and data science

Julia is better than both.

I'll take explicit value- and reference-semantics any day over all of this.

The thing that swift really bothers me is the discouragement of using pointer. It is so often that something can be done easily with some usage of pointers at the very low level of the structure. But in swift, not only do you have to declare it as UnsafePointer, the usage is pretty disconnecting from the other swift codes. So I would rather go back to objc for some really low-level staffs.

This is such a random comparison lol

"JS is better" change my mind..

I understood nothing

This is like nerd wars lol.