# Structs
A struct is a nominal record. Fields are private unless declared `pub`. Each field
has a type, and construction checks required fields and their values.
```shy
struct Station
{
pub name: String,
pub platforms: Integer,
pub note: String | (),
}
let $station = Station(name: "Riverside", platforms: 3)
echo $station.name $station.platforms $station.note
```
```text
Riverside 3 ()
```
Use attached named construction: `Station(name: ..., platforms: ...)`.
Fields admitting `()` may be omitted. Unknown, repeated, or missing required
arguments are errors. Construction does not guess values for required fields.
## Encapsulated state
A public factory can construct private storage. External callers use its named
parameters; a matching raw construction inside the constructor initializes fields.
```shy
struct Gauge { reading: Integer }
fn Gauge::new($initial: Integer): Gauge { Gauge(reading: $initial) }
fn Gauge::get_value(): Integer { $self.::reading }
fn Gauge::set_value($value: Integer) { $self.::reading = $value }
let $gauge = Gauge(initial: 5)
$gauge.value = 12
echo $gauge.value
```
```text
12
```
Raw `.::reading` observes the same access rules while bypassing property dispatch.
It is not a way for unrelated code to access private fields. Getters and setters
can have independent visibility. Getter-only properties are read-only; setter-only
properties cannot be read.
Constructors and getters can return errors, and return contracts are validated.
A constructor recursively calling itself without reaching raw construction is
rejected. Fields and nested collections obey ordinary value-copy semantics.
Native resource fields can still hold shared handles; see [I/O](Bytes-and-IO).
A deferred `let $station: Station` binding must be initialized before reading.
An optional `Station | ()` instead has an immediately readable unit default.
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Related: [Methods](Methods-and-Properties) · [Named types](Named-Types-and-Unions) · [JSON](JSON)