Learning to program in rust

This was my experience too, until I learned a few things.

If you're coming from another programming language, the equivalent capabilities you're probably used to are Box, dyn, and Rc.
Dynamic dispatch (dyn) isn't really necessary a lot of the time. Identify where you absolutely need it and solve everything else through other means.
You wind up with lifetime specifier problems if you try to do a lot with references (&). Instead, try to re-think your structs and functions using composition and clone/copy instead. It's less efficient, but it's easier to optimize a running program, too.
Rust enum, match, if let, and ? are weird, but are where you get the most leverage in the language. Try to master them.
derive[...] is a first-class feature with a lot of standard lib support. Always use this to make your custom types mesh with the standard lib more seamlessly.
If you are experienced with the "Design Patterns" book, you absolutely need this: https://rust-unofficial.github.io/patterns/intro.html
Macros are an advanced feature, but help get you around limitations in generics and the type system in general. it really is worth knowing, and like the preprocessor in C/C++, isn't avoidable at the intermediate level.
The compiler digs deep into your code to figure out types where they're not explicitly declared. I've seen it reach into the return type, call-spec, and function calls within that function, to figure out types for things. This is very hard to observe without an IDE that's checking syntax on the fly. Lean into both of those for more readable and maintainable code.
if and match are expressions, not statements! You can use either block to evaluate to a single value, useful in composite expressions like let. Example; let x=if y>20 { y } else { 0 }; Or use them to return values from functions (w/o need of a return statement).

Call me a weirdo but the more errors a compilers give me the happier (albeit a bit frustrated) I am. That stuff generally surfaces in a way or another… and I prefer at compile time 🙂

That said I haven’t spent quality time with Rust yet… so not sure if there are a lot of nitpicks (ala go) or these are valgrind-level of “holy s*** I am so grateful to this tool” 😃

The borrow checker makes things a bit more complicated to get running, definitely takes some getting used to when you come from a non-memory safe language. But the compiler is really helpful throughout almost all mistakes, often directly providing an explanation and a suggested fix. One of my favorites programming experiences so far
- ...definitely takes some getting used to when you come from a non-memory safe language...
  I actually think it's more like the opposite. The compiler takes the normal rules you apply to avoid issues with a non-memory safe language like C/C++ and enforces them explicitly where memory safe languages don't have those rules at all. I think lifetimes are much more confusing if you've never dealt with a user after free and usually let GC deal with it.
  Also yes the compiler warnings and errors are amazing, the difference between rustc and gcc is night and day.

Skill Issue.

For reals though adopting a functional style of programming makes rust extremely pleasant . It’s only when people program in object oriented styles that this gets annoying.

No loops, and no state change make rust devs happy devs.

I just started learning rust like two days ago and I haven’t had too many issues with OOP so far… is it going to get considerably worse as the complexity of my projects increases?
- The thing with OOP, particularly how it's used in GCed languages, is that it's all about handing references out to wherever and then dealing with the complexity of not knowing who has access to your fields via getters & setters, or by cloning memory whenever it's modified in asynchronous code.
  Rust has quite the opposite mindset. It's all about tracking where references go. It pushes your code to be very tree-shaped, i.e. references typically¹ only exist between a function and the functions it calls underneath. This is what allows asynchronous code to be safe in Rust, and I would also argue that the tree shape makes code easier to understand, too.
  But yeah, some of the patterns you might know from OOP will not work in Rust for that reason. You will likely need to get into a different mindset over time.
  Also just in case: We are talking OOP in the sense of the paradigm, i.e. object-oriented.
  Just using objects, i.e. data with associated functions/methods, that works completely normal in Rust.
  ¹) If you genuinely need references that reach outside the tree shape, which is mostly going to be the case, if you work with multiple threads, then you can do so by wrapping your data structures in Arc<Mutex<_>> or similar. But yeah, when learning, you should try to solve your problems without these. Most programs don't need them.
- It will become more complex when you start needing circular references in your datastructures.
- You’ll be fine. You will learn the lifetime stuff and all will work out. It’s not that bad to be honest.
- Worse in the sense of more errors, sure, but as you go you’ll pick up more of the rust patterns of thinking and imo it’s very worth it. It’s an odd blend and can be a bit verbose but I definitely prefer it to a pure OO or pure functional style language personally

Learning C, that smasher would never have stopped.

It would also be emitting significantly less helpful messages.
- "What messages?"
  Lol yes

In my experience rust compiler simply moves the errors to earlier stage of development. With rust I write something and get bunch of errors right in the IDE. I spend some time fixing those and when all the compilation errors are gone in 99% of cases the code works and does what it's supposed to do.

With other languages I write some code and the compiler/interpreter says it's all good. I then run it, get bunch of errors and have to do some debugging, move back and forth between the editor and the command line/browser/application and fix all the bugs one by one.

So yeah, rust compiler complains a lot but it's to make your life easier, not harder. For me working rust way is just much more pleasant. I get immediate visual clues about the errors right in the IDE. When I finally get it right and all the errors dispersal it's like solving a small puzzle. You know you got it and it feels good. With other languages you think you got it all the time only to find another bug when you run it. Doing it this way is much more frustrating.

The old school method of learning a programming language, database, framework or whatever was to read books and take classes, do a series of exercises that teach you how to use the features, and the errors you get if you don't do it right. Then you write code that way for like 10-15 years.

The Information Age method is to find some sample code, copypaste into an editor and hit Compile, then paste compile errors into google and fix them until there are no more. Then hit Run and copypaste/fix runtime errors until there are no more runtime errors. Old-schoolers used to call this hacking, but now it's called not having time to deeply learn the hot new thing because before you do you'll have to start over with the next hot new thing.

The last language I learned was Rust, I did a mix of the two. I read through the canonical Rust book and then got to coding because I learn more deeply when I can apply what I've learned. It's still a tricky language to keep a conceptual model of in your head though.
Books, classes, and documentation can also be lacking for new tech.

This is my experience every time I return to learning rust. I’m guessing that if I used it more often than once a quarter with hobby projects I’d stop falling into the same traps.

I find that the error messages themselves are a great tool for learning when it comes to Rust.
- Eh, I’m not entirely sold on that idea.
  I think they do a good job of pointing out “this is a behavior/feature of Rust you need to understand.” However they can send you down the wrong path of correction.
  The compiler error mentioning static lifetime specifiers of &str demonstrates both. It indicates to the developer that ownership and scopes will play a significant role when defining and accessing data. The error though will guide them towards researching how to define static lifetimes and possibly believe that they will need to set this in their functions and structs. Each time you look at questions about this error in places like Stack Overflow with example code you’ll find suggested solutions explaining that a manually-defined static lifetime isn’t necessary to resolve the problem.
Yeah, these become a lot less relevant with routine.
Avoiding the main-thread panicking is mostly just a matter of not using .unwrap() and .expect().
String vs. &str can mostly be solved by generally using owned datatypes (String) for storing in structs and using references (&str) for passing into function parameters. It does still happen that you forget the & at times, but that's then trivial to solve (by just adding the &).
"temporary value dropped while borrowed" can generally be avoided by not passing references outside of your scope/function. You want to pass the owned value outside. Clone, if you have to.
"missing lifetime specifier" is also largely solved by not storing references in structs.
- The last two points are the kind of design advice I need to see. I’m probably so used to the C/C++ concept of passing by reference to prevent copies of complex data being generated that I forget how Rust’s definition of a reference is different.

C is the way.3̶̧̧̳̉ẻ̵͙̗͍͒h̶͈̗̊͘o̷̡̳̥̒͐̇f̷͍̳͕̐{̸͇̀̒?̷̤͇̀̊p̴̰̆̍̕

The weird part of rust is replacing straight forward semicolons from other languages with the more verbose .unwrap();.

Just kidding, don't lecture me about it.

?
The amount of people on the internet seriously complaining that both Rust error handling sucks and that .unwrap(); is too verbose is just staggering.
- I will say this: for me, learning rust was 80% un-learning habits from other languages.
  People tend to not like it when they have to change habits, especially if those took a long (and painful) time to acquire.
  In this particular case, this is the same complaint Go faced with its form of explicit error handling. And Java, for that matter.
  Honestly, Rust does a killer job of avoiding checked exceptions and verbose error hooks by way of the ? operator, and requiring all possible match branches to be accounted for. If you embrace errors fully, by using Result<> and custom Error types, your program gets a massive boost in robustness for not a lot of fuss. I recently learned that it gets even better if you embrace enum as a way to define error values, and make sure it implements useful traits like From and Display. With that, error handling code gets a lot more succinct, permitting one to more easily sift through different error values after a call (should you need to). All of that capability far exceeds any perception of clunkyness, IMO.