How do you work with closures in Rust?

Question

Accepted Answer

**Closure** — anonymous function with captured environment.

**Basic:**
```rust
let add = |a, b| a + b;
println!("{}", add(2, 3));  // 5
```

**Capturing:**
```rust
let name = String::from("Alice");

// Borrow
let greet = || println!("Hello, {}!", name);
greet();

// Mutable borrow
let mut count = 0;
let mut inc = || count += 1;
inc();

// Move
let name = String::from("Alice");
let greet = move || println!("Hello, {}!", name);
greet();
```

**As argument:**
```rust
fn apply<F: Fn(i32) -> i32>(f: F, x: i32) -> i32 {
    f(x)
}

let result = apply(|x| x * 2, 5);
```

**Key:** Closures capture environment, use move for ownership.

Rust: How do you work with closures in Rust?