---
title: Variables
description: Local state management with type inference and explicit mutability.
icon: Variable
---

In Mist, variables follow the language-wide `type name` convention. For local scope, the `var` keyword provides type inference, while explicit types can be used for clarity or strictness.

## Basic Declaration

Variables are declared using the `var` keyword for automatic type inference. Like Rust, variables are immutable by default.

```mist
var message = "Hello Mist";
var count = 42;
```

## Mutability

To allow a variable to be reassigned, use the `mut` modifier after the `var` keyword or the explicit type.

```mist
var mut score = 0;
score = 100;

f32 mut price = 19.99;
price = 14.99;
```

## Explicit Typing

```mist
u64 large_id = 1000234;
bool is_active = true;
```

## Arrays

```mist
var list = [1, 2, 3];       // Standard init
var zeros = [0; 10];         // Repeat notation: ten zeroes
```

## Pattern Destructuring

```mist
(i32, i32) (x, y) = get_coordinates();
(String, i32) (name, age) = get_user_info();
```

## Constants

Constants are immutable values evaluated at compile time with an explicit type.

```mist
const i32 MAX_RETRIES = 5;
const str* VERSION = "1.0.4";
```

## Key Characteristics

- **Predictable Order**: Whether using `var` or an explicit type, the name always follows the "source" of its data.
- **Safety First**: Immutability by default prevents accidental state changes.
- **Zero-Cost Inference**: Type inference is handled entirely at compile time.
- **Shadowing**: Mist supports variable shadowing within the same scope.