Charles Cooper

Charles Cooper


Interacting with Assembly in Rust

For many Rust developers, the process of producing a binary from their Rust code is a straightforward process that doesn’t require much thought. However, modern compilers are complicated programs in and of themselves and may yield binaries that perform very differently in response to a minor change in the source code.

In diagnosing performance issues like this, inspecting the output of the compiler can be helpful. The Rust compiler emits various types of output, one of which is assembly. Rust also has facilities for embedding assembly. In this guide, we’ll explore what the Rust community has to offer for extracting and embedding assembly.

Viewing assembly

To view the assembly output of each tool, we’ll use the following example program.

const NAMES: [&'static str; 10] = [
    "Kaladin", "Teft", "Drehy", "Skar", "Rock", "Sigzil", "Moash", "Leyten", "Lopen", "Hobber",

fn main() {

pub fn roll_call() {
    println!("SOUND OFF");
    for name in NAMES.iter() {
        println!("{}: HERE!", name);
    let num_present = NAMES.len();
    println!("All {} accounted for!", num_present);

#rust #web-development

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Interacting with Assembly in Rust

Serde Rust: Serialization Framework for Rust


*Serde is a framework for serializing and deserializing Rust data structures efficiently and generically.*

You may be looking for:

Serde in action

Click to show Cargo.toml. Run this code in the playground.


# The core APIs, including the Serialize and Deserialize traits. Always
# required when using Serde. The "derive" feature is only required when
# using #[derive(Serialize, Deserialize)] to make Serde work with structs
# and enums defined in your crate.
serde = { version = "1.0", features = ["derive"] }

# Each data format lives in its own crate; the sample code below uses JSON
# but you may be using a different one.
serde_json = "1.0"


use serde::{Serialize, Deserialize};

#[derive(Serialize, Deserialize, Debug)]
struct Point {
    x: i32,
    y: i32,

fn main() {
    let point = Point { x: 1, y: 2 };

    // Convert the Point to a JSON string.
    let serialized = serde_json::to_string(&point).unwrap();

    // Prints serialized = {"x":1,"y":2}
    println!("serialized = {}", serialized);

    // Convert the JSON string back to a Point.
    let deserialized: Point = serde_json::from_str(&serialized).unwrap();

    // Prints deserialized = Point { x: 1, y: 2 }
    println!("deserialized = {:?}", deserialized);

Getting help

Serde is one of the most widely used Rust libraries so any place that Rustaceans congregate will be able to help you out. For chat, consider trying the #rust-questions or #rust-beginners channels of the unofficial community Discord (invite:, the #rust-usage or #beginners channels of the official Rust Project Discord (invite:, or the #general stream in Zulip. For asynchronous, consider the [rust] tag on StackOverflow, the /r/rust subreddit which has a pinned weekly easy questions post, or the Rust Discourse forum. It's acceptable to file a support issue in this repo but they tend not to get as many eyes as any of the above and may get closed without a response after some time.

Download Details:
Author: serde-rs
Source Code:
License: View license

#rust  #rustlang 

Running Rust in the Browser with Web Assembly

I’ve recently been working on a Rust course for the Qvault app. In order to write a more engaging course, I want students to be able to write and execute code right in the browser. As I’ve learned from my previous posts on this topic, the easiest way to sandbox code execution on a server is to not execute code on a server. Enter Web Assembly, stage left.

For those of you who don’t care about how it works, and just want to give it a try, checkout the demo: Rust WASM Playground.

How It Works

The architecture is fairly simple:

  • User writes code in the browser
  • Browser sends code to server
  • Server adds some glue and compiles code to WASM
  • Server sends WASM bytes or compiler errors back to browser
  • Browser runs WASM and displays console output, or shows compiler errors

Writing code and shipping it to the server hopefully needs no explanation, it’s a simple text editor coupled with the fetch API. The first interesting thing we do is compile the code on the server.

Compiling the Code

Qvault’s server is written in Go. I have a simple HTTP handler with the following signature:

func (cfg config) compileRustHandler(w http.ResponseWriter, r *http.Request)

At the start of the function we unmarshal the code which was provided in a JSON body:

type parameters struct {
	Code string

decoder := json.NewDecoder(r.Body)
params := parameters{}
err := decoder.Decode(&params)
if err != nil {
	respondWithError(w, 500, "Couldn't decode parameters")

Next, we create a temporary folder on disk that we’ll use as a “scratch pad” to create a Rust project.

usr, err := user.Current()
if err != nil {
	respondWithError(w, 500, "Couldn't get system user")
workingDir := filepath.Join(usr.HomeDir, ".wasm", uuid.New().String())
err = os.MkdirAll(workingDir, os.ModePerm)
if err != nil {
	respondWithError(w, 500, "Couldn't create directory for compilation")
defer func() {
	err = os.RemoveAll(workingDir)
	if err != nil {
		respondWithError(w, 500, "Couldn't clean up code from compilation")

As you can see, we create the project under the .wasm/uuid path in the home directory. We also defer an os.RemoveAll function that will delete this folder when we are doing handling this request.

#golang #languages #rust #wasm #rust #rustlang #wasm #web assembly

Rust Lang Course For Beginner In 2021: Guessing Game

 What we learn in this chapter:
- Rust number types and their default
- First exposure to #Rust modules and the std::io module to read input from the terminal
- Rust Variable Shadowing
- Rust Loop keyword
- Rust if/else
- First exposure to #Rust match keyword

=== Content:
00:00 - Intro & Setup
02:11 - The Plan
03:04 - Variable Secret
04:03 - Number Types
05:45 - Mutability recap
06:22 - Ask the user
07:45 - First intro to module std::io
08:29 - Rust naming conventions
09:22 - Read user input io:stdin().read_line(&mut guess)
12:46 - Break & Understand
14:20 - Parse string to number
17:10 - Variable Shadowing
18:46 - If / Else - You Win, You Loose
19:28 - Loop
20:38 - Match
23:19 - Random with rand
26:35 - Run it all
27:09 - Conclusion and next episode


Lydia  Kessler

Lydia Kessler


ULTIMATE Rust Lang Tutorial! - Publishing a Rust Crate

The ultimate Rust lang tutorial. Follow along as we go through the Rust lang book chapter by chapter.

📝Get the FREE Rust Cheatsheet:

The Rust book:​​

0:00​ Intro
0:43 Release Profiles
3:00 Documentation Comments
4:32 Commonly Used Sections
5:04 Documentation Comments as Tests
5:50 Commenting Contained Items
6:29 Exporting a Public API
8:44 Setting up Account
9:54 Adding Metadata to a New Create
12:14 Publishing to
12:49 Removing Version from
13:37 Outro

#letsgetrusty​​ #rust​lang​ #tutorial

#rust #rust lang #rust crate

Tyree  Becker

Tyree Becker


Linux Executables: From Assembly to C and Rust

In this video we explore more about Linux ELF executables focusing on the difference between executables and object files generated by using assembly, C, and Rust. In the second half we explore dynamic loading!

fasterthanlime’s blog:

#linux executables #assembly #rust #c