Anatomy Of a Rust Program

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

Rust, like many other languages, has a special main function, which is the first function that runs in any Rust program.

println! calls a Rust #macro.

! indicates calling a #macro as opposed to a normal function.

Before you run a Rust program, it must be compiled, using the Rust compiler, and the rustc command, to which a file is given as an argument.

Rust is AOT compiled, meaning if you compile a program and give it to someone, they can execute it without having Rust installed.

Hello, Cargo!

[[Cargo]] is Rust's build system and package manager.

Cargo uses TOML, as it's configuration format.

Filename: Cargo.toml:

[package]
name = "hello_cargo"
version = "0.1.0"
authors = ["Your Name <you@example.com>"]
edition = "2018"
[dependencies]

[package] is a heading that indicates the following statements configure a package.

The next four lines (2-5), set the config info Cargo needs to compile a program- the name, version, author, and Rust edition to use.

[dependencies], is the start of a section to list project dependencies.

In #Rust, packages of code are called crates.

Use cargo buildto build your program.

This command generates an executable file.

The first time you run the build command, a Cargo.lock file is generated to keep track of dependency versioning.

Use cargo runto compile and run the resulting executable in consecutively.

Cargo can tell if source files have changed, and will not attempt to rebuild a program with an existing binary if the source code hasn't changed.

Use cargo check to make sure your code will compile (without generating an executable).

When your project is ready for release, use cargo build --release to compile it with optimizations.