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.
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
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@Ephera it will be very cheap because you will create only a container with a reference &str to your string. To view data is the preferred way.
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…