bevy/crates/ron/docs/extensions.md
2020-05-22 18:07:26 -07:00

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## RON extensions
RON has extensions that can be enabled by adding the following attribute at the top of your RON document:
`#![enable(...)]`
# unwrap_newtypes
You can add this extension by adding the following attribute at the top of your RON document:
`#![enable(unwrap_newtypes)]`
This feature enables RON to automatically unwrap simple tuples.
```rust
struct NewType(u32);
struct Object {
pub new_type: NewType,
}
```
Without `unwrap_newtypes`, because the value `5` can not be saved into `NewType(u32)`, your RON document would look like this:
``` ron
(
new_type: (5),
)
```
With the `unwrap_newtypes` extension, this coercion is done automatically. So `5` will be interpreted as `(5)`.
``` ron
#![enable(unwrap_newtypes)]
(
new_type: 5,
)
```
# implicit_some
You can add this extension by adding the following attribute at the top of your RON document:
`#![enable(implicit_some)]`
This feature enables RON to automatically convert any value to `Some(value)` if the deserialized struct requires it.
```rust
struct Object {
pub value: Option<u32>,
}
```
Without this feature, you would have to write this RON document.
```ron
(
value: Some(5),
)
```
Enabling the feature would automatically infer `Some(x)` if `x` is given. In this case, RON automatically casts this `5` into a `Some(5)`.
```ron
(
value: 5,
)
```