Variables & Types

Learn about variable declaration, type annotations, and the primitive types available in Soli.

Variable Declaration

Variables are declared using the let keyword. Soli uses block scoping.

let

Declares a mutable variable with optional type annotation.

let x = 10
let name = "Soli"
let is_active = true

Type Annotations

You can explicitly specify types for documentation, IDE support, and runtime validation.

# Explicit type annotations
let name: String = "Alice";
let age: Int = 30;
let temperature: Float = 98.6;
let is_active: Bool = true;
let scores: Int[] = [95, 87, 92];
let user: Hash = {"name": "Alice", "age": 30};

Primitive Types

Soli provides six primitive types:

Int

64-bit signed integer

42, -100, 9_000_000

Float

64-bit floating-point

3.14, 0.001, 2.5e10

Decimal

Fixed-precision for financial calculations

19.99D, 0.0675D

String

UTF-8 string

"Hello", "Line 1\nLine 2"

Bool

Boolean

true, false

Null

Absence of value

null

Constants

const

Use const for values that should never change.

const MAX_CONNECTIONS = 100;
const DEFAULT_TIMEOUT = 30;
const PI = 3.14159265359;

# const values cannot be reassigned
# MAX_CONNECTIONS = 200;  # This would cause an error

Scope

Variables in Soli are block-scoped:

let x = 1;

if (true) {
    let y = 2;      # y only visible in this block
    let x = 3;      # shadows outer x
    print(x);       # Output: 3 (inner x)
}

print(x);           # Output: 1 (outer x)

Language Overview Operators