Kieran‘s Blog

Day 1: Morning#

1. What is Rust#

Rust is a statically compiled language with similar functionality to cpp.

• rustc uses LLVM as its backend.
• Rust and cpp are suitable for similar scenarios.
  • Extremely high flexibility.
  • High level of control.
  • Can be scaled down to very constrained devices such as microcontrollers.
  • No runtime and garbage collection.
  • Focuses on program reliability and safety without sacrificing any performance.

2. Why choose Rust#

Some unique features of Rust:

• Compiler memory safety.
• No runtime undefined behavior.
• Modern programming language features.

2.1 Compile-time guarantees#

Compile-time static memory management:

• No uninitialized variables.
• No memory leaks.
• No "double free".
• No "use after free".
• No NULL pointers.
• No forgotten mutexes.
• No data races between threads.
• No iterator invalidation.

2.2 Runtime guarantees#

Rust has no runtime undefined behavior:

• Array access has boundary checks.
• Integer overflow is defined (panic or wrap-around).

2.3 Modern features#

Language features:

• Enums and pattern matching.
• Generics.
• Zero-cost abstractions for FFI.
• Zero-cost abstractions.

Tools:

• Powerful compiler error messages.
• Built-in dependency manager.
• Built-in support for unit tests.
• Excellent implementation of the Language Server Protocol.

3. Basic syntax#

3.1 Scalar types#

• iN, uN, and fN occupy N bits,
• isize and usize occupy space equal to the size of a pointer,
• char is 32 bits wide,
• bool is 8 bits wide.

3.2 Compound types#

fn main() {
	let mut a: [i8; 10] = [42; 10];
	a[5] = 0;
	println!("a: {:?}", a);
}

Assignment and access of tuples:

fn main() {
    let t: (i8, bool) = (7, true);
    println!("t.0: {:?}", t.0);
    println!("t.1: {:?}", t.1);
}

3.3 References#

Rust also provides reference types.

fn main() {
    let mut x: i32 = 10;
    let ref_x: &mut i32 = &mut x;
    *ref_x = 20;
    println!("x: {x}");
}

Note the difference between let mut ref_x: &i32 and let ref_x: &mut i32, the former declares a mutable reference where we can modify the value it is bound to, while the latter declares a reference to a mutable variable.