> For the complete documentation index, see [llms.txt](https://wu-lang.gitbook.io/guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://wu-lang.gitbook.io/guide/syntax/structs.md).

# Structs

The following code shows basic use of a struct.

```fsharp
Point: struct {
    x: float
    y: float
}
```

{% hint style="info" %}
Comma separation is optional in struct initialization and definition.
{% endhint %}

`Point` is thus defined as a data structure containing two float fields `x`and `y`.

You can define instances of `Point`like so:

```fsharp
point0 := new Point {
    x: 100
    y: 200
}

point1: Point = new Point {
    x: 1
    y: 2
}
```

Struct fields are always mutable. You can access fields of a struct like this:

```fsharp
point := new Point {
    x: 100
    y: 100
}

point x = 20
point y = point x
```

{% hint style="info" %}
Wu does not use `.`for field access, because doing so would be gross.
{% endhint %}

We can also implement methods on our structs. This will feel very familiar for people with Rust experience.

```fsharp
Vector: struct {
    x: float,
    y: float
}

implement Vector {
    new: fun(x, y) -> Self {
        Vector {
            x: x,
            y: y
        }
    }

    length: fun(self) -> float {
        (self x^2 + self y^2)^0.5
    }

    normalize: fun(self) {
        len := self length()
        
        self x /= len
        self y /= len
    }
}

a := Vector new(100, 100)
a normalize()
```

{% hint style="info" %}
`Self` aliases whatever struct type you're implementing on.
{% endhint %}


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://wu-lang.gitbook.io/guide/syntax/structs.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.