Variables & Mutability

AzLang enforces explicit distinction between immutable constants and mutable variables.

1. Constants (`const`)

By default, data should remain immutable. Use the const keyword to declare constants:

const int max_retries = 5
const str host = "127.0.0.1"
const float pi = 3.14159

Once defined, attempting to reassign a const identifier will produce a compile-time semantic error during the validation phase.

When state needs to change over time, declare the variable using var:

var int counter = 0
counter = counter + 1

var str status = "pending"
status = "ready"

AzLang supports type inference for basic expressions, while allowing explicit type annotations for maximum clarity:

// Explicit type annotation
const int port = 8080

// Mutable variable with type
var int connections = 0
connections = 1

For custom structures, enums, and module interfaces, explicit types are required at structural boundaries.