Variables & Constants

Luma offers a simple yet expressive system for declaring variables and constants. The syntax is concise and readable, focusing on clarity and type safety.

Variable Declaration

You define a variable using this pattern:

name: str = "Alice"
age: int = 30
price: float = 9.99
active: bool = true

• The syntax is always: name: type = value
• Types are explicit for clarity and safety.
• All variables are mutable by default.

Constants with lock

To declare an immutable constant, prefix it with lock. This ensures the variable cannot be reassigned after its declaration.

lock PI: float = 3.14
lock WELCOME: str = "Hello"

Attempting to reassign PI will result in a compile-time error.

Optional Variables

Use ? to mark a variable as nullable (i.e., it may be nil):

email: ?str = nil
score: ?int = "42".to_int()

Nullable types are useful when a value may or may not exist.

Type Inference (Not yet implemented)

Luma may support type inference in the future, but currently all variable types must be explicitly declared.

Examples

name: str = "Luma"
count: int = 42
price: float = 19.95
valid: bool = false

lock VERSION: str = "1.0"
maybeAge: ?int = nil

Best Practices

• Use lock for constants like configuration or math values.
• Always choose the most accurate type (e.g. float vs int).
• Prefer ?type over using raw nil when nullability is intended.