Types And Values

Every value has a concrete type; Nenu does not rely on truthiness or implicit cross-type conversion.
Primitive, named, optional, collection, and structural types follow different compatibility rules.
Inference removes repeated type spelling, but it never weakens the type contract.

The Type Families

Family	Examples	Identity rule
Primitive	`string`, `number`, `bool`, `time`	Compatible by primitive kind.
Media	`image`, `file`	Fixed metadata objects supplied by the platform.
Named value type	`ExpenseDraft`	Structurally compatible with an equal shape.
Entity	`Room`, `Expense`	Nominal: the declared entity name matters.
Enum	`ExpenseStatus`	Nominal: variants belong to one enum.
Optional scalar	`string?`, `Expense?`	Either the wrapped value or absent.
Collection	`Expense[]`, `number{}`	Element type and container shape must match.
Structural shape	`{ label: string, amount: number }`	Field names, types, and optional markers must match; order does not matter.

Literal Values

code

1string title = "Internet"2number amount = 72.503bool shared = true4time recorded_at = time.now()5string? note = ?67number[] shares = [24.17, 24.17, 24.16]8number{} balances = { alice: 24.17, sam: -24.17 }

Strings use double quotes. Numbers cover integer and decimal values. Booleans are exactly true or false. The lone ? value means absent and only fits an optional scalar. Array and map literals infer from their members when non-empty.

Inference Keeps A Real Type

code

1number total = 72.502string label = "Internet"

Both tabs produce a number named total and a string named label. Inference only discovers the type from the first value. A later incompatible assignment is still rejected.

code

1total = 72.502total = 8034// Invalid: total remains number5total = "eighty"

Construction And Compatibility

code

1type BalanceRow {2  label: string3  amount: number4}56BalanceRow row = {7  amount: 24.178  label: "Sam owes Alex"9}1011{ label: string, amount: number } same_shape = row

The named value type and the inline shape are compatible because they have the same fields and types. Field order does not matter. A stored entity with those fields remains a different nominal type because entity identity carries storage meaning.

No Truthiness Or Silent Conversion

Intent	Wrong	Correct
Check a number	`if amount { ... }`	`if amount > 0 { ... }`
Check a string	`if title { ... }`	`if title != "" { ... }`
Check an optional	`if note { ... }`	`with note as text { ... }`
Convert a value	Assume assignment converts it	Use a documented method or keep matching types.

Common Mistakes

Mistake	Use instead
Treat a number or string as a boolean	Write an explicit comparison.
Assume assignment converts between types	Keep compatible types or use a documented method.
Treat entities as structural shapes	Remember that entity identity is nominal.
Infer an empty collection or absent value	Write the explicit expected type.

Continue Learning

Built-In Types Learn the language and platform-provided types available before application modeling.Optionals And Absence Learn the exact meaning of ? and ??.