Derive Macro bevy_derive::DerefMut
source · #[derive(DerefMut)]
{
// Attributes available to this derive:
#[deref]
}
Expand description
Implements DerefMut
for structs. This is especially useful when utilizing the newtype pattern.
For single-field structs, the implementation automatically uses that field.
For multi-field structs, you must specify which field to use with the #[deref]
attribute.
DerefMut
requires a Deref
implementation. You can implement it manually or use
Bevy’s derive macro for convenience.
§Example
§Tuple Structs
Using a single-field struct:
use bevy_derive::{Deref, DerefMut};
#[derive(Deref, DerefMut)]
struct MyNewtype(String);
let mut foo = MyNewtype(String::from("Hello"));
foo.push_str(" World!");
assert_eq!("Hello World!", *foo);
Using a multi-field struct:
use bevy_derive::{Deref, DerefMut};
#[derive(Deref, DerefMut)]
struct MyStruct<T>(#[deref] String, PhantomData<T>);
let mut foo = MyStruct(String::from("Hello"), PhantomData::<usize>);
foo.push_str(" World!");
assert_eq!("Hello World!", *foo);
§Named Structs
Using a single-field struct:
use bevy_derive::{Deref, DerefMut};
#[derive(Deref, DerefMut)]
struct MyStruct {
value: String,
}
let mut foo = MyStruct {
value: String::from("Hello")
};
foo.push_str(" World!");
assert_eq!("Hello World!", *foo);
Using a multi-field struct:
use bevy_derive::{Deref, DerefMut};
#[derive(Deref, DerefMut)]
struct MyStruct<T> {
#[deref]
value: String,
_phantom: PhantomData<T>,
}
let mut foo = MyStruct {
value:String::from("Hello"),
_phantom:PhantomData::<usize>
};
foo.push_str(" World!");
assert_eq!("Hello World!", *foo);