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since: my first project
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this post was submitted on 21 Apr 2024
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Rust
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I took a very quick look at the code and one thing I noticed, is that you're using
&String.For a parameter in a function, you always want to use
&strinstead, as explained here: https://doc.rust-lang.org/book/ch04-03-slices.html#string-slices-as-parametersI believe, it's also not a thing to return
&String(nor to store it in a struct). I don't have as solid of an explanation for it, it's just not something I see much in Rust code (and in the chapter above, they do use a&stras return value, too).Maybe someone else can weigh in on that.
The same applies for:
&[]rather than&Vec&Pathrather than&PathBuf&OsStrrather than&OsStringI would also recommend using Clippy. I think, you can just run
cargo clippyand it'll work.It's a linter and will tell you lots of code style issues (like using
&Stringas a parameter).If you've never run it, it might spit out a lot of warnings at first, but working through them can teach you quite some things.
Thank you very much. I’ll change it. I did run cargo clippy, but it didn’t complained anything anymore before I published the code. 🙂
One question to return value
Option<&String>:is it better to change to
Option<&str>or&Option<String>if the value in the struct is aOption<String>? The latter sounds more logical to me.@larix @Ephera it's better to return an Option<&str> as a String may DeRef to &str.
For example
self.name.as_deref()
Hmm, interesting. The documentation tells me, it creates a new Option value, and allocating memory every time someone just wants to look at a value could be pretty bad.
But I guess, an Option of a reference never needs to allocate memory, because it'll either be a pointer to a value (
Some) or a pointer to null (None). Right?Well, that explains why it's technically possible.
As for why
Option<&str>is preferrable then:It hides away your internals. Your caller should only care whether they can get the value or not (
Somevs.None), not what the precise reason is. That reason or your internal structure might change.@larix
Yes, that makes sense too. Great!
I’ve updated the code as recommended.
@Ephera@lemmy.ml @jcbritobr@mastodon.social
Hmm, not quite sure why Clippy didn't say anything then. I think, it was a
Option<&String>which I had seen as a parameter type. Maybe it doesn't complain when it's wrapped in an Option...