[khold_stare]

Isn't that the opposite of the intended implementation? I don't write Rust, but I think your implementation will always return either `None` or the "fallback" value with the `"-default"` key. In the article, the crucial part is that if the first `map.get_mut()` succeeds, that is what is returned.

[saghm]

Whoops, you're definitely right. This is why I shouldn't try to be productive in the morning.

[brabel]

A great example of how "if it compiles, it runs correctly" is bullshit.

[unshavedyak]

You're reaching pretty hard there. Your assertion is a massive strawman, the implication seeming to be that "every problem in your logic won't exist if it compiles" - no one thinks you can't write bad logic in any language.

Rather it's about a robust type system that gives you tooling to cover many cases at compile time.

Even if we ignore logic, Rust has plenty of runtime tooling and runtime issues can still happen as a result. A complaint i often have about Bevy (despite loving it!) is that it has a lot of runtime based plugins/etc which i'd prefer to be compile time. Axum for example has a really good UX while still being heavily compile time (in my experience at least).

"If it compiles it works" is still true despite my complaints. Because i don't believe the statement even remotely implies you can't write bad logic or bad runtime code in Rust.

[oivey]

This particular example explicitly dodges compile time checking for some ad-hoc (but likely safe) runtime behavior. It’s not a strawman at all. It’s a classic example of how sometimes the compiler can’t help you, and even worse, how programmers can defeat their ability to help you.

[unshavedyak]

Right but their statement (as i parsed it) was that the the "if it compiles it works" phrase is bullshit. Since there's some cases where it obviously won't be true.

At best it's ignorant of what that phrase means, in my view.

[lelanthran]

> Since there's some cases where it obviously won't be true.

That's not how I've seen it used every that I have seen it used.

> At best it's ignorant of what that phrase means, in my view.

I think your opinion on what the phrase means is a minority opinion.

[unshavedyak]

If it was as wide as the OP said then it means errors, panics, and especially Unsafe wouldn't exist. Even if we ignore unclean sources (say network errors/etc), this isn't a Proofed language where programs in it cannot possibly fail.

Besides, it likely is very possible to write programs that cannot fail in Rust. This usually means encoding state into the type system (enums included), but few go through that work. They know what corners they're cutting. Further proving that they know their program can fail.

Hell, Rust itself can fail. I struggle to imagine how this is perceived as some long-con from the Rust PR team to convince people Rust programs cannot be written with incorrect logic.

[oivey]

I think they were highlighting that that phrase is bullshit. It’s trivial to escape many compile time checks.

[unshavedyak]

Yea, but that's my argument - that they're being dense (i imagine on purpose?). The phrase doesn't mean that nothing can fail at runtime. Of course it doesn't.

Rather that we have many tools to write a program that can be written with many compile time checks. For example many representations of state can be describe in compile time checks via enums, type transitions, etc.

[saghm]

Honestly, I think the majority of the times I've said that sentence has been after running code that has an obvious mistake (like the code I posted above)!