I don't believe Julia or Python is "best practice" over Rust. I even empathize with the opinion that explicitness may be preferential sometimes. But you _must_ be able to see how Rust's syntax overload obfuscates the core business logic, right?
Sure, business logic is more readable in something like OCaml than in Rust. On the other hand, Rust isn't really worse than something like Java, and I like having more information than what you have in Python. I'll also add that Rust is often chosen for speed and reliability, and that part of that syntax is here to guarantee that. It's not directly business logic in the traditional sense, but it's something you expect from your code.
All in all, Rust is still not at the level of the "platonic ideal for syntaxes", especially not for most of the code I write (business logic for web apps, which wouldn't need Rust's speed). Still, in the realms of programming languages that are used, it's one of the best.
FWIW `__` doesn't mean "this is part of the implementation", it means "I'm designing a class for inheritance and I don't want child classes to stop on my attributes".
No. Python certainly does not have a concept of private code[0]. The Python community has a suggestion of things being implementation details.
Surely you can see that absolutely would not be good enough for a language which strives for static correctness? And even more so as the soundness of `unsafe` blocks often relies on the invariants of the type it's used in?
[0] well that's not entirely true, I guess there's native code.
fn f(x: impl Test) { ... }
fn f<T: Test>(x: T) { ... }
That pub? It's punching waaay above its weight! Having things private by default protects against semver hazards too, but it's also the major tool that enable writing safe code that uses unsafe { .. } blocks underneath. That's because a single unsafe block typically taints the whole module it's contained (such that even safe code needs a safety review). Being able to write safe abstractions of unsafe code is the pull of Rust so people need to get it right.
For example, setting the field len of a Vec to a value larger than what's initialized in its buffer will cause UB when accessing that memory; if this field weren't private, making a safe Vec would be impossible (likewise, a function that could set the len to any value must be private, etc).
So pub can only be used for things that are safe to export, and people should be careful with that.
Here's my least favorite syntax from there: that damn Ok(..). Ok-wrapping sucks. There were proposals to remove it, but they were rejected. There's a library that removes it [0], and people should use it. It also makes the Result<..> return type implicit in the function signature too.
[0] https://boats.gitlab.io/blog/post/failure-to-fehler/#but-abo...