Variables
Nyx distinguishes between immutable bindings (let) and mutable variables (var). Types are written explicitly after a colon, and string interpolation with ${...} makes it easy to embed values inside strings.
Code
// Variables: let (inmutable), var (mutable), tipos básicos e interpolación
fn main() -> int {
// let es inmutable
let nombre: String = "Nyx"
let version: int = 12
let activo: bool = true
let precio: float = 3.14
print("Nombre: ${nombre}")
print("Version: ${version}")
print("Activo: ${activo}")
// var es mutable — se puede reasignar
var contador: int = 0
contador = contador + 1
contador = contador + 1
print("Contador: ${contador}")
// Interpolación con expresión
let doble: int = contador * 2
print("Doble: ${doble}")
// Concatenación de strings
let saludo: String = "Hola, " + nombre + "!"
print(saludo)
return 0
}Output
Nombre: Nyx Version: 12 Activo: true Contador: 2 Doble: 4 Hola, Nyx!
Explanation
let declares an immutable binding. Once assigned, you cannot reassign it — any attempt to do so is a compile-time error. This is the default and preferred form in Nyx, since most values do not need to change.
var declares a mutable variable. You can reassign it freely after its initial declaration. Use var only when mutation is genuinely needed — counters, accumulators, and loop variables are good candidates.
The four basic scalar types shown here are String (UTF-8 text), int (64-bit signed integer), bool (true or false), and float (64-bit double-precision floating point).
String interpolation uses the ${expr} syntax inside a double-quoted string. Any expression can appear inside the braces, and its value is automatically converted to a string. You can also concatenate strings with the + operator.