# RegisterFunction(string,Func\<TResult>)

Method in [Library](https://docs.yarnspinner.dev/2.1/api/csharp/yarn/yarn.library)

## Summary

Registers a new function that returns a value, which can be called from a Yarn program.

```csharp
public void RegisterFunction<TResult>(string name, Func<TResult> implementation)
```

## Parameters

| Name                                  | Description                                           |
| ------------------------------------- | ----------------------------------------------------- |
| `string` name                         | The name of the function.                             |
| `System.Func<TResult>` implementation | The method to be invoked when the function is called. |

## Type Parameters

| Name    | Description                      |
| ------- | -------------------------------- |
| TResult | The return type of the function. |