1
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submitted 7 hours ago by dontblink@feddit.it to c/rust@lemmy.ml

This is what I've found:

In C and C++, two different operators are used for calling methods: you use . if you’re calling a method on the object directly and -> if you’re calling the method on a pointer to the object and need to dereference the pointer first. In other words, if object is a pointer, object->something() is similar to (*object).something().

What about Rust?

Rust doesn’t have an equivalent to the -> operator. Instead, Rust has what is called automatic referencing and dereferencing.

In other words, the following are the same:

p1.distance(&p2); (&p1).distance(&p2); Note: this automatic referencing behavior works because methods have a clear receiver-the type of self. Given the receiver and name of a method, Rust can figure out definitively whether the method is reading (&self), mutating (&mut self), or consuming (self).

I am not sureI understood the note correctly, what does it mean that there is a clear receiver? Also, doesn't Rust actually have an operator for dereferencing (*) as well?

2
20
submitted 1 week ago by kionite231@lemmy.ca to c/rust@lemmy.ml
3
43
submitted 1 week ago by jplatte@discuss.tchncs.de to c/rust@lemmy.ml

axum is an ergonomic and modular web framework built with Tokio, Tower, and Hyper

4
48
submitted 3 weeks ago by cypherpunks@lemmy.ml to c/rust@lemmy.ml

It seems quite clear that rust users use hyper but few of them want to work on making it work for a C project like curl, and among existing curl users there is virtually no interest in hyper. The overlap in the Venn diagram of the two universes is not big enough.

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Learning Rust (lemmy.ca)
submitted 3 weeks ago by kionite231@lemmy.ca to c/rust@lemmy.ml

Hello,

I have started learning Rust. I have only made a fibonaci series program so far but I would make more complex program as I progress in learning Rust :D

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submitted 3 weeks ago* (last edited 2 weeks ago) by jplatte@discuss.tchncs.de to c/rust@lemmy.ml

axum is a web application framework that focuses on ergonomics and modularity.

Hey! If you're using axum, I would be happy if you tried the first release candidate of the upcoming v0.8.0, and shared any feedback you have. That's all :)

7
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submitted 3 weeks ago by nutomic@lemmy.ml to c/rust@lemmy.ml
8
8
submitted 4 weeks ago* (last edited 4 weeks ago) by dontblink@feddit.it to c/rust@lemmy.ml

I am trying to understand the std::process::Termination trait.

As I'm not really used to read libraries, I took this as a challenge to try understanding a bit more about how to read them as well.

I think trying to build a library would give me better understanding, but for now...

Termination is quite easy, from the trait page I can see that this trait has single method: report, which returns an ExitCode.

pub trait Termination {
    fn report(self) -> ExitCode;
}

But when I try to dig in further and i read the page related to ExitCode, it confuses me a bit.

ExitCode is a struct, therefore it behaves like a type with many fields which define the types contained in the struct.

I cannot really understand what's the point of this type.. I don't see any fields defined in the struct and this part confuses me a lot:

The standard library provides the canonical SUCCESS and FAILURE exit codes as well as From for ExitCode for constructing other arbitrary exit codes.

I even thought this meant it was an enum which had the SUCCESS, FAILURE etc as variants, but this does not seem the case.

Can you help me to understand how this specific structs work, what exactly does it do and how I should read library pages like this one?

9
20
submitted 4 weeks ago* (last edited 4 weeks ago) by aclarke@lemmy.world to c/rust@lemmy.ml

I was recently furloughed from work, so in between job applications, I decided to polish off Sonarr support in my Managarr TUI. Thus, I'm very proud to announce the beta release of Managarr with Sonarr support!

TL;DR: Managarr is a TUI and CLI for managing your Servarr instances. As of now, it now supports both Radarr and Sonarr and all the features that are available in the UI are also available in the CLI for scripting and additional automation.

The new version has the following features:

  • Wider platform support (Windows, Mac, Linux, x86_64 and arm64)
  • View your library, downloads, blocklist, episodes
  • View details of a specific series, or episode including description, history, downloaded file info, or the credits
  • View your host and security configs from the CLI to programmatically fetch the API token, among other settings
  • Search your library
  • Add series to your library
  • Delete series, downloads, indexers, root folders, and episode files
  • Trigger automatic searches for series, seasons, or episodes
  • Trigger refresh and disk scan for series and downloads
  • Manually search for series, seasons, or episodes
  • Edit your series and indexers
  • Manage your tags
  • Manage your root folders
  • Manage your blocklist
  • View and browse logs, tasks, events queues, and updates
  • Manually trigger scheduled tasks
  • Manually trigger scheduled tasks
  • And more!

Here's some screenshots of the Sonarr tab:

Thanks to everyone's feedback when I first posted the alpha release here, this version sports a handful of additional performance improvements and platform support.

This is now technically in beta, so if anyone encounters any issues, please let me know!

10
14
submitted 1 month ago by tracyspcy@lemmy.ml to c/rust@lemmy.ml
11
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submitted 1 month ago by tracyspcy@lemmy.ml to c/rust@lemmy.ml
12
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submitted 1 month ago by qaz@lemmy.world to c/rust@lemmy.ml

cross-posted from: https://lemmy.world/post/22673996

This mod is written in an unconventional way: it is written in Rust. The Rust code is here. It uses JNI and JVMTI to interact with Java objects. The only Java code in this mod is for loading the compiled native binary into memory.

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Hey there! I'm starting my journey to the learning of Rust. I have been coding only with Python for 6 years now and last year, I had to code in JavaScript using VueJS for my job (I never workedeon frontend).

Now, I have a personal project idea which I'd like to create. I could do it in Python but I want to learn Rust. I've looked up on the Internet but may be some answers are too old or someone here can point me to something I haven't seen yet.

What do you recommand for webdev? I guess I need to code the back in Rust and use a JavaScript framework for the front. My backend will be for a REST API (my app will need to manage users and organisations).

Bonus question if you can recommend a BDD framework. I think there is something named Cucumber. Is it good?

Thanks a lot ♥️🦀

14
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submitted 1 month ago* (last edited 1 month ago) by raldone01@lemmy.world to c/rust@lemmy.ml

Hello,

I was playing around with rust and wondered if I could use const generics for toggling debug code on and off to avoid any runtime cost while still being able to toggle the DEBUG flag during runtime. I came up with a nifty solution that requires a single dynamic dispatch which many programs have anyways. It works by rewriting the vtable. It's a zero cost bool!

Is this technique worth it?

Probably not.

It's funny though.

Repo: https://github.com/raldone01/runtime_const_generics_rs/tree/v1.0.0

Full source code below:

use std::mem::transmute;
use std::sync::atomic::AtomicU32;
use std::sync::atomic::Ordering;

use replace_with::replace_with_or_abort;

trait GameObject {
  fn run(&mut self);
  fn set_debug(&mut self, flag: bool) -> &mut dyn GameObject;
}

trait GameObjectBoxExt {
  fn set_debug(self: Box<Self>, flag: bool) -> Box<dyn GameObject>;
}

impl GameObjectBoxExt for dyn GameObject {
  fn set_debug(self: Box<Self>, flag: bool) -> Box<dyn GameObject> {
    unsafe {
      let selv = Box::into_raw(self);
      let selv = (&mut *selv).set_debug(flag);
      return Box::from_raw(selv);
    }
  }
}

static ID_CNT: AtomicU32 = AtomicU32::new(0);

struct Node3D<const DEBUG: bool = false> {
  id: u32,
  cnt: u32,
}

impl Node3D {
  const TYPE_NAME: &str = "Node3D";
  fn new() -> Self {
    let id = ID_CNT.fetch_add(1, Ordering::Relaxed);
    let selv = Self { id, cnt: 0 };
    return selv;
  }
}

impl<const DEBUG: bool> GameObject for Node3D<DEBUG> {
  fn run(&mut self) {
    println!("Hello {} from {}@{}!", self.cnt, Node3D::TYPE_NAME, self.id);
    if DEBUG {
      println!("Debug {} from {}@{}!", self.cnt, Node3D::TYPE_NAME, self.id);
    }
    self.cnt += 1;
  }

  fn set_debug(&mut self, flag: bool) -> &mut dyn GameObject {
    unsafe {
      match flag {
        true => transmute::<_, &mut Node3D<true>>(self) as &mut dyn GameObject,
        false => transmute::<_, &mut Node3D<false>>(self) as &mut dyn GameObject,
      }
    }
  }
}

struct Node2D<const DEBUG: bool = false> {
  id: u32,
  cnt: u32,
}

impl Node2D {
  const TYPE_NAME: &str = "Node2D";
  fn new() -> Self {
    let id = ID_CNT.fetch_add(1, Ordering::Relaxed);
    let selv = Self { id, cnt: 0 };
    return selv;
  }
}

impl<const DEBUG: bool> GameObject for Node2D<DEBUG> {
  fn run(&mut self) {
    println!("Hello {} from {}@{}!", self.cnt, Node2D::TYPE_NAME, self.id);
    if DEBUG {
      println!("Debug {} from {}@{}!", self.cnt, Node2D::TYPE_NAME, self.id);
    }
    self.cnt += 1;
  }

  fn set_debug(&mut self, flag: bool) -> &mut dyn GameObject {
    unsafe {
      match flag {
        true => transmute::<_, &mut Node2D<true>>(self) as &mut dyn GameObject,
        false => transmute::<_, &mut Node2D<false>>(self) as &mut dyn GameObject,
      }
    }
  }
}

fn main() {
  let mut objects = Vec::new();
  for _ in 0..10 {
    objects.push(Box::new(Node3D::new()) as Box<dyn GameObject>);
    objects.push(Box::new(Node2D::new()) as Box<dyn GameObject>);
  }

  for o in 0..3 {
    for (i, object) in objects.iter_mut().enumerate() {
      let debug = (o + i) % 2 == 0;
      replace_with_or_abort(object, |object| object.set_debug(debug));
      object.run();
    }
  }
}

Note:

If anyone gets the following to work without unsafe, maybe by using the replace_with crate I would be very happy:

impl GameObjectBoxExt for dyn GameObject {
  fn set_debug(self: Box<Self>, flag: bool) -> Box<dyn GameObject> {
    unsafe {
      let selv = Box::into_raw(self);
      let selv = (&mut *selv).set_debug(flag);
      return Box::from_raw(selv);
    }
  }

I am curious to hear your thoughts.

15
20
submitted 1 month ago* (last edited 1 month ago) by dontblink@feddit.it to c/rust@lemmy.ml

In python, when you install stuff with pip, it is recommended to use a venv, to avoid breaking dependencies for a program when uninstalling another one, or when two programs need two different versions of the same dependence.

I was wondering if with Rust is the same, or if Cargo manages it all on its own (kind of like apt does), and I shouldn't care about it.

Also since I know Linux kernel is using some Rust, isn't there a risk of breaking my system if I uninstall a program that need some deps that the system itsel needs?

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submitted 1 month ago* (last edited 1 month ago) by thevoidzero@lemmy.world to c/rust@lemmy.ml

TLDR: Searching for person holding professor position to officially act as a committee member on a US PhD defense

Hi all,

I'm in a non CS field. I'm doing PhD in hydrology and I'm good at Geospatial Analysis, data analysis, visualization, modeling and such. I really like programming and have been making open source programs, contributing to open source programs and such. And have been learning rust for last 2 years.

For my PhD dissertation I'm doing a project where I'll be using Rust to make a program with compiled plugin system that can do generalized river related tasks including data analysis and visualization. I have professors in GIS and hydrology to guide those aspects, but I don't have anyone on software side to ask questions, or to look at my work. I tried emailing some people I have seen with open source projects on GIS+rust, but no response.

I'm ideally looking for someone that holds a professor position for my committee who is good with either rust, GIS related algorithms development, and programming languages. However, it woud also be helpful to just have someone woth knowledge about such things. In either scenario, credit and authorship will be given.

I appreciate any response even telling where i could find someone matching the above description. :)

Edit: I can also provide my previous projects in GitHub, websites and such before you decide in messages.

17
7
submitted 1 month ago* (last edited 1 month ago) by gomp@lemmy.ml to c/rust@lemmy.ml

I have two functions that are similar but can fail with different errors:

#[derive(Debug, thiserror::Error)]
enum MyError {
  #[error("error a")]
  MyErrorA,
  #[error("error b")]
  MyErrorB,
  #[error("bad value ({0})")]
  MyErrorCommon(String),
}

fn functionA() -> Result<String, MyError> {
  // can fail with MyErrorA MyErrorCommon
  todo!()
}

fn functionB() -> Result<String, MyError> {
  // can fail with MyErrorB MyErrorCommon
  todo!()
}

Is there an elegant (*) way I can express this?

If I split the error type into two separate types, is there a way to reuse the definition of MyErrorCommon?


(*) by "elegant" I mean something that improves the code - I'm sure one could define a few macros and solve that way, but I don't want to go there

edit: grammar (rust grammar)

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What do you code in Rust? (lemmy.blahaj.zone)

I've only been coding with Python/Javascript since I started my career. I do APIs and websites frontend. I don't really understand what is interesting in learning an other language. For example, I could learn Ruby, but I'd do the same thing I already do.

Rust, C/C++ tho seem to me to be languages to code other things. Hence my question : what do you code? If possible, make distinction between personal projects and professional projects.

19
10
submitted 1 month ago* (last edited 1 month ago) by dontblink@feddit.it to c/rust@lemmy.ml

Let's say I have a struct Event which implements the method permalink:

struct Event {
    base_url: String,
    rel_permalink: String,
    permalink: String,
    title: String,
}

impl Event {
    fn permalink(&self) -> String {
        let permalink = format!("{}{}", self.base_url, self.rel_permalink);
        permalink
    }
}

The method takes 2 fields of the struct and the target would be to return the definition of another field.

Later I instantiate an event1: Event:

let event1 = Event {
                base_url: base_url,
                rel_permalink: rel_permalink.to_string(),
                title: node.value().name().to_string(),
                permalink = permalink(),
            };

Essentially I would like the field permalink to be the value returned by the method permalink, is something like this possible, is this correct? I couldn't find something similar in the docs..

Pheraps using an associated function as constructor would be a better way to handle a similar situation?

Thank you so much!

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21
20
submitted 2 months ago by dontblink@feddit.it to c/rust@lemmy.ml
fn get_links(link_nodes: Select) -> Option<String> {

        let mut rel_permalink: Option<String> = for node in link_nodes {
            link = String::from(node.value().attr("href")?);

            return Some(link);
        };

        Some(rel_permalink)
    }

This is what I'm trying to do, and I've been stuck with this code for an hour, I simply don't know how to put this function togheter.. Essentially I would like to take some link_nodes and just return the link String, but I'm stuck in the use of Option with the ? operator.. Pheraps trying to write it with match would clear things out(?)

Also I come from JavaScript in which expressions do not have their own scope, meaning I'm having troubles to understand how to get out a variable from a for loop, should I initialize the rel_permalink variable as the for loop result?

This are the errors i get:

error[E0308]: mismatched types
  --> src/main.rs:55:49
   |
55 |           let mut rel_permalink: Option<String> = for node in link_nodes {
   |  _________________________________________________^
56 | |             link = String::from(node.value().attr("href")?);
57 | |
58 | |             return Some(link);
59 | |         };
   | |_________^ expected `Option<String>`, found `()`
   |
   = note:   expected enum `Option<String>`
           found unit type `()`
note: the function expects a value to always be returned, but loops might run zero times
  --> src/main.rs:55:49
   |
55 |         let mut rel_permalink: Option<String> = for node in link_nodes {
   |                                                 ^^^^^^^^^^^^^^^^^^^^^^ this might have zero elements to iterate on
56 |             link = String::from(node.value().attr("href")?);
   |                                                          - if the loop doesn't execute, this value would never get returned
57 |
58 |             return Some(link);
   |             ----------------- if the loop doesn't execute, this value would never get returned
   = help: return a value for the case when the loop has zero elements to iterate on, or consider changing the return type to account for that possibility
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submitted 2 months ago by JRepin@lemmy.ml to c/rust@lemmy.ml

gccrs is a work-in-progress alternative compiler for Rust being developed as part of the GCC project. GCC is a collection of compilers for various programming languages that all share a common compilation framework. You may have heard about gccgo, gfortran, or g++, which are all binaries within that project, the GNU Compiler Collection. The aim of gccrs is to add support for the Rust programming language to that collection, with the goal of having the exact same behavior as rustc.

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CXX-Qt 0.7 release (www.kdab.com)
submitted 2 months ago by JRepin@lemmy.ml to c/rust@lemmy.ml

CXX-Qt is a set of Rust crates for creating bidirectional Rust ⇄ C++ bindings with Qt. It supports integrating Rust into C++ applications using CMake or building Rust applications with Cargo. CXX-Qt provides tools for implementing QObject subclasses in Rust that can be used from C++, QML, and JavaScript.

For 0.7, we have stabilized the cxx-qt bridge macro API and there have been many internal refactors to ensure that we have a consistent baseline to support going forward. We encourage developers to reach out if they find any unclear areas or missing features, to help us ensure a roadmap for them, as this may be the final time we can adapt the API. In the next releases, we’re looking towards stabilizing the cxx-qt-build and getting the cxx-qt-lib APIs ready for 1.0.

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submitted 2 months ago by aclarke@lemmy.world to c/rust@lemmy.ml

After almost 3 years of work, I've finally managed to get this project stable enough to release an alpha version!

I'm proud to present Managarr - A TUI and CLI for managing your Servarr instances! At the moment, the alpha version only supports Radarr.

Not all features are implemented for the alpha version, like managing quality profiles or quality definitions, etc.

Here's some screenshots of the TUI:

Additionally, you can use it as a CLI for Radarr; For example, to search for a new film:

managarr radarr search-new-movie --query "star wars"

Or you can add a new movie by its TMDB ID:

managarr radarr add movie --tmdb-id 1895 --root-folder-path /nfs/movies --quality-profile-id 1

All features available in the TUI are also available via the CLI.

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submitted 2 months ago by dontblink@feddit.it to c/rust@lemmy.ml

Hi! I'm trying to learn Rust, as a little project, I'm trying to build a web scraper that will scrape some content and rebuild it with a static site generator, or using it for making POST requests.

I'm still at a very early stage and I still don't know much, the simplest error handling strategy I know is using match with Result.

To my eyes, this syntax looks correct, but also looks kind of a lot of lines for a simple http request.

I know the reqwest docs suggest to handle errors with the ? operator, which I don't know yet, therefore I'm just using what I know now.

fn get_document(permalink: String) -> Html {
        let html_content_result = reqwest::blocking::get(&permalink);
        let html_content = match html_content_result {
            Ok(response) => response,
            Err(error) => panic!("There was an error making the request: {:?}", error),
        };

        let html_content_text_result = html_content.text();
        let html_content_text = match html_content_text_result {
            Ok(text) => text,
            Err(error) =>
                panic!(
                    "There was an error getting the html text from the content of response: :{:?}",
                    error
                ),
        };

        let document = Html::parse_document(&html_content_text);

        document
    }

As for my understanding, this is what I'm doing here: I'm making an http request, if i get a Response, I try to get the text out of the response body, otherwise I handle the error by panicking with a custom message. Getting the text out of the request body is another passage that requires error handling, therefore I use the match expression again to get the text out and handle the possible error (In what circumstances can extracting the text of a response body fail?).

Then I can finally parse the document and return it!

I wonder if it is a correct and understandable way of doing what I've in mind.

Do you think this would be a suitable project for someone who is at chapter 7 of the Rust book? I feel like i actually need to build somethiong before keep going with the theory!

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