# Structs

> Structs define named record types with typed fields. Structs may also be generic.

Website: https://harnlang.com/spec/language/15-structs.html

This page documents Harn, which is pre-1.0. Language, standard library, and CLI APIs may change. If the intended version is unclear, clarify before using this page.

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## Structs

Structs define named record types with typed fields. Structs may also be
generic.

### Struct declaration

```harn
struct Point {
  x: int
  y: int
}

struct User {
  name: string
  age: int
}

struct Pair<A, B> {
  first: A
  second: B
}
```

Fields are declared with `name: type` syntax, one per line.

### Struct construction

Struct instances can be constructed with the struct name followed by
a named-field body:

```harn
struct Point { x: int, y: int }
struct User { name: string, age: int }
struct Pair<A, B> { first: A, second: B }
const p = Point { x: 3, y: 4 }
const u = User { name: "Alice", age: 30 }
const pair: Pair<int, string> = Pair { first: 1, second: "two" }
```

### Field access

Struct fields are accessed with dot syntax, the same as dict property
access:

```harn
harness.obs.log(p.x)    // 3
harness.obs.log(u.name) // "Alice"
```

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## Read next

- [Enums](https://harnlang.com/spec/language/14-enums.md)
- [Impl blocks](https://harnlang.com/spec/language/16-impl-blocks.md)