too-many-lists VS CppCoreGuidelines

You seem to have a preset opinion, and I'm not sure you are interested in re-evaluating it. So this is not written to change your mind.

I've developed production code in C, C++, Rust, and several other languages. And while like pretty much everything, there are situations where it's not a good fit, I find that the solutions tend to be the most robust and require the least post release debugging in Rust. That's my personal experience. It's not hard data. And yes occasionally it's annoying to please the compiler, and if there were no trait constraints or borrow rules, those instances would be easier. But way more often in my experience the compiler complained because my initial solution had problems I didn't realize before. So for me, these situations have been about going from building it the way I wanted to -> compiler tells me I didn't consider an edge case -> changing the implementation and or design to account for that edge case. Also using one example, where is Rust is notoriously hard and or un-ergonomic to use, and dismissing the entire language seems premature to me. For those that insist on learning Rust by implementing a linked list there is https://rust-unofficial.github.io/too-many-lists/.

Advent of Code was okay until I encounterd a problem that required a graph, tree or linked list to solve, where I hit a wall. Most coding exercises are similar--those requiring arrays and hashmaps and sets are okay, but complex data structures are a PITA. (There is an online course dedicated to linked lists in Rust but I couldn't grok it either). IMO you should simply skip problems that you can't solve with your current knowledge level and move on.

I feel obligated to point to the original cannon literature: https://rust-unofficial.github.io/too-many-lists/

I started learning Rust and like how the compiler is fussy about things. My plan was to implement the data structures I knew, but I got stuck at the singly linked list's remove() method. I've read the book as well, but I have no clue how to simplify this further:

My impression from the article is that Zig provides several different hashtables and not all of them are broken in this way.

This reminds me of Aria's comment in her Rust tutorial https://rust-unofficial.github.io/too-many-lists/ about failing to kill LinkedList. One philosophy (and the one Rust chose) for a stdlib is that this is only where things should live when they're so commonly needed that essentially everybody needs them either directly or to talk about. So, HashTable is needed by so much otherwise unrelated software that qualifies, BloomFilter, while it's real useful for some people, not so much. Aria cleaned out Rust's set of standard library containers before Rust 1.0, trying to keep only those most people would need. LinkedList isn't a good general purpose data structure, but, it was too popular and Aria was not able to remove it.

Having multiple hash tables feels like a win (they're optimized for different purposes) but may cost too much in terms of the necessary testing to ensure they all hit the quality you want.

> Cyclic references can be dealt with runtime safety checks too - like Rc and Weak.

Indeed. Starting out with code sprinkled with Rc, Weak, RefCell, etc is perfectly fine and performance will probably not be worse than in any other safe languages. And if you do this, Rust is pretty close to those languages in ease of use for what are otherwise complex topics in Rust.

A good reference for different approaches is Learn Rust With Entirely Too Many Linked Lists https://rust-unofficial.github.io/too-many-lists/

Second, once you've finished something introductory like The Book, read Learning Rust With Entirely Too Many Linked Lists. It really helped me to understand what ownership and borrowing actually mean in practical terms. If you don't mind paying for learning materials, a lot of people recommend Programming Rust, Second Edition by Blandy, Orendorff, and Tindall as either a complement, follow-up, or alternative to The Book.

The standard library types are guaranteed to be in a useful state after being moved from (the term "valid state" is used for this). Of course, that doesn't mean that your own types have to, but the C++ Core Guidelines suggest doing so [1].

1: https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines...

It’s in the cpp core guidelines: https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines...

std::reference_wrapper still can’t save you from yourself, but its slightly better.

Slightly tongue in cheek answer: it is easy to write this kind of code in C++ without having C involved, hence style guides will usually have a prominent guideline specifically against this type of code[1].

In Rust, I think you only really run into this issue when interacting with C (or otherwise engaging in unsafe code), so for normal Rust coding it doesn't need to be spelled out as a guideline. And the Rustonomicon[2], the go-to resource for unsafe Rust, isn't really written as a set of guidelines. At least from a brief search, I found it harder to find a Rust page that specifically says "don't do this".

1: E.g. https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines..., the first guideline in the "resource management" section.

2: https://doc.rust-lang.org/nomicon/intro.html

> You are actually just arguing for the sake of arguing here.

I'm very much not doing that.

I'm really tired of reading claims that "C++ is actually safe if you follow these very very simple rules", and then the "simple rules" are either terrible for performance, not actually leading to memory safe code (often by ignoring facts of life like the practices of the standard libraries, iterator and reference invalidation, or the existence of multithreaded programming), or impossible to reliably follow in an actual codebase. Often all three of these, too.

I mean the most complete version of "just follow rules" is embodied by the C++ core guidelines[1], a 20k lines document of about 116k words, so I think we can drop the "very very simple" qualifier at this point. Many of these rules among the more important are not currently machine-enforceable, like for instance the rules around thread safety.

Meanwhile, the rules for Rust are:

1. Don't use `unsafe`

2. there is no rule #2

*That* is a very very simple rule. If you don't use unsafe, any memory safety issue you would have is not your responsibility, it is the compiler's or your dependency's. It is a radical departure from C++'s "blame the users" stance.

That stance is imposed by the fact that C++ simply doesn't have the tools, at the language level, to provide memory safety. It lacks:

- a borrow checker

- lifetime annotations

- Mutable XOR shared semantics

- the `Send`/`Sync` markers for thread-safety.

Barring the addition of each one of these ingredients, we're not going to see zero-overhead, parallel, memory-safe C++. Adding these is pretty much as big of a change to existing code as switching to Rust, at this point.

> Use the abstractions within the rules and you won't get issues, use compiler flags and analyzers on CI and you don't even need to remember the rules.

I want to see the abstractions, compiler flags and analyzers that will *reliably* find:

- use-after-free issues

- rarely occurring data races in multithreaded code

Use C++ if you want to, but please don't pretend that it is memory safe if following a set of simple rules. That is plain incorrect.

[1]: https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines

If you aren't aware of the c++ core guidelines[1] - it should be on your radar.

Also, it might not be a popular opinion, but I think Bjarne's books are just fine.

A Tour of C++ (3rd edition) [2]

Principles and Practice Using C++ (3rd Edition) was just published in april 2023 [3]

[1] https://github.com/isocpp/CppCoreGuidelines/blob/master/CppC...

You need to talk to Bjarne and Herb...

"C++ Core Guidelines" - https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines