The Rust Programming Language

系列文章学习 Part 2

Installation and Hello World

Updating and Uninstalling

After you've installed Rust via rustup, to update:

rustup update

To uninstall Rust and rustup

rustup self uninstall

Hello World Program

fn main() {
    println!("Hello, world!");
}

rustfmt formatter:

Provide standard style across Rust projects. The Rust team has included this tool with the standard Rust distribution, like rustc. Use it!

rustfmt main.rs

4 import details to notice:

• First, Rust style to indent with four spaces, not a tab
• println! - Rust macro. Using a ! means to call a macro instead of a normal function. (Detail in Chapter 19)
• Pass a string as argument.
• End with a semicolon(;).

Hello, Cargo!

Cargo is Rust's build system and package manager. Most Rustaceans use this tool to manage their Rust projects.

• Project building
• Download libraries and build them(dependencies.)

cargo new hello_cargo
cd hello_cargo

• a Cargo.toml file: TOML format style configuration file
• a src directory: source files source code
• a .git Git repository along with a .gitignore file

Move into Cargo

If you started a project that doesn't use Cargo,as we did with the "Hello, world" project, you can conver it to a project that does use Cargo.

Move the project code into the src directory and create an appropriate Cargo.toml file.

Cargo Run and Cargo Check

cargo build build a project. cargo run can compile the code and then run the resulting(build and directly run in ./target/debug/hello_cargo).

Cargo Check cargo check, quickly checks your code without producing an executable.

Why not want an executable?

Speed up. Often, cargo check is much faster than cargo build, because it skips the step of produing an executable. Frequentlly use when continually checking your work while writing the code.

Recap what we've learned so far about Cargo"

• We can build a project using cargo build.
• We can build and run a project in one step using cargo run.
• We can build a project without producing a binary to check for errors using cargo check
• Instead of saving the result of the build in the same directory as our code, Cargo stores it in the target/debug directory.

Building for Release

Use cargo build --release to compile it with optimizations, create an executable in target/release instead of target/debug. The optimizations make your Rust code run faster(but take longer time to compile).