Variables

Variables in Nic are declared with let. They can optionally have type annotations.

Basic Declaration

fn main() -> unit {
    // With explicit type
    let x: i32 = 42;
    
    // With type inference
    let y = 100;  // inferred as i32
    
    // Declaration without initialization
    let z: i32;
    z = 50;
    
    println("Variables declared!");
    return;
}

Type Annotations

Type annotations follow the variable name with a colon:

fn main() -> unit {
    let age: i32 = 25;
    let pi: f64 = 3.14159;
    let name: string = "Alice";
    let active: bool = true;
    
    return;
}

Mutability

All variables in Nic are mutable by default. You can reassign them freely:

fn main() -> unit {
    let count: i32 = 0;
    count = 1;
    count = 2;
    count = count + 1;  // count is now 3
    
    return;
}

Constants

Use const for compile-time constants that cannot be changed:

const MAX_SIZE: i32 = 1024;
const PI: f64 = 3.14159265359;

fn main() -> unit {
    let radius: f64 = 5.0;
    let area: f64 = PI * radius * radius;
    
    return;
}

Constants must:

• Have an explicit type
• Be initialized with a compile-time constant expression
• Be declared at module level (not inside functions)

Shadowing

You can declare a new variable with the same name, which shadows the previous one:

fn main() -> unit {
    let x: i32 = 5;
    let x: i32 = x + 10;  // shadows previous x
    let x: string = "now a string";  // can even change type
    
    return;
}

Summary

Feature	Syntax	Example
Variable	let name: Type = value;	let x: i32 = 42;
Inferred	let name = value;	let x = 42;
Constant	const NAME: Type = value;	const MAX: i32 = 100;

Next

Learn about the Types you can use with variables.