Variables

There are two type of variables: val and var.

val are immutable, both in the binding & the underlying value, so they can't be modified in anyway.

val name = "John"
val lastname = "Doe"

The underlying value is also immutable, so attempting to indirectly modify them will also fail:

val pet = Dog("Nala")
pet.name = "Rufus"    // This is an error
pet.add_years(1)      // If a method changes data, it's also an error

var are mutable. The binding & the value is mutable.

var pet = "Nala"
pet = "Rufus"    // OK

Type annotations

Types are marked with a colon, then the type:

val name: String  = "Pablo"
val age: u64      = 32
val married: bool = false

However, variables can omit a type annotation just fine.

Types

Nara has primitive types and reference types. Primitives are: u8, i32, u32, f32, i64, u64, f64, bool.

Reference types live on the heap. The most fundamental one is String.

More info about them in their article.