Rust @programming.dev larix @programming.dev 1 mo. ago

since: my first project

Filter input by timestamp

This is my first project in rust, called: since. A small tool to filter logfiles or any other files with a timestamp in it, by a given timestamp.

For example:

since 1h /var/log/messages prints all lines from the last hour. since 00:00 /var/log/messages prints all lines since 00:00.

It would be nice if you could take a look at the code. What would you change, what should I change?

I’m not a professional programmer, this is just a hobby, but I want to learn as much as possible.

9 comments

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 &str instead, as explained here: https://doc.rust-lang.org/book/ch04-03-slices.html#string-slices-as-parameters

I 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 &str as return value, too).
Maybe someone else can weigh in on that.

The same applies for:

&[] rather than &Vec

&Path rather than &PathBuf

&OsStr rather than &OsString

I would also recommend using Clippy. I think, you can just run cargo clippy and it'll work.
It's a linter and will tell you lots of code style issues (like using &String as 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 a Option<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, 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...
- Thanks, that was a lot of info I didn't know either. I was wondering how to use clippy...
Very neat idea!
- Thanks!

You've viewed 9 comments.