Types and Values

Primitive types, compound values, inference, unions, absence, and casts.

Primitive types

The primitive set is intentionally broad enough for systems code and small enough to stay readable.

Integers exist at fixed widths, plus isize and usize for pointer-sized values.
f32 and f64 cover floating-point math.
char, str, bool, nil, (), and ! fill out the basic value model.

Compound types

Tuples, arrays, slices, lists, maps, and sets each represent a different storage and ownership story.

[T; N] is a fixed-size array.
&[T] is a borrowed slice.
List<T> owns a growable heap buffer.
Map<K, V> and Set<T> are heap-managed collections with their own mutation APIs.

Absence

La3 keeps one absence value and gives it two useful presentations.

nil is the runtime value. Option<T> is the explicit enum wrapper. The two map to the same underlying absence case so the reader can choose the lighter or louder spelling depending on context.

T | nil is the lightweight form for local flow.
Option<T> is the explicit form for signatures and APIs.
??, ?., map, unwrap_or, and ? cover the common control patterns.

let host = lookup(name) ?? "localhost"
let first: Option<str> = items.first()

Inference and casts

Type inference removes noise, but it never hides a real conversion.

A binding without annotation takes the initializer type.
Unsuffixed integers default to i32; unsuffixed floats default to f64.
There is no implicit numeric widening or narrowing.
as marks the exact place where a conversion occurs.