---
title: Functions
description: Function declarations, self parameters, return types, and unsafe functions.
icon: SquareFunction
---

```mist
// Return type is `void` (unit)
void greet(str& name)
{
    println!("Hello, {name}");
}

// With return type
i32 add(i32 a, i32 b)
{
    return a + b;
}

// Expression body (last expression is the return value)
i32 square(i32 x)
{
    x * x
}

// Public function
pub i32 multiply(i32 a, i32 b)
{
    a * b
}

// Generic function
T identity<T>(T value)
{
    value
}

// Unsafe function
unsafe i32 dangerous()
{
    42
}
```

### Self Parameter

Methods can take `self`, `mut self`, `&self`, `&mut self`, and `&'a self` / `&'a mut self` with lifetimes:

```mist
pub void set_value(&mut self, i32 v)
{
    self.value = v;
}
```