Expand description
Arena
An arena allows to allocate objects dynamically, and bind them to a specific common lifetime. All objects allocated on the arena live as long as the arena does. This allows us to easily link nodes together.
§Example
use std::cell::RefCell;
struct Person<'ctx> {
age: u32,
name: String,
friends: RefCell<Vec<&'ctx Person<'ctx>>>,
}
impl<'ctx> Person<'ctx> {
fn new(age: u32, name: impl Into<String>) -> Self {
Self {
age,
name: name.into(),
friends: RefCell::default(),
}
}
fn add_friend(&self, person: &'ctx Person<'ctx>) { self.friends.borrow_mut().push(person); }
fn print(&self) {
print!(
"Hi, I'm {}, and I'm {} years old. These are my friends: ",
self.name, self.age
);
for f in self.friends.borrow().iter() {
print!("{}, ", f.name);
}
println!();
}
}
arena::define_arenas!(
people: Person<'ctx>,
);
pub fn main() {
let arena = Arena::new();
let luke = Person::new(12, "Luke").alloc_into(&arena);
let susan = Person::new(15, "Susan").alloc_into(&arena);
let laura = Person::new(8, "Laura").alloc_into(&arena);
let alejandro = Person::new(28, "Alejandro").alloc_into(&arena);
luke.add_friend(susan);
luke.add_friend(alejandro);
alejandro.add_friend(laura);
laura.add_friend(luke);
susan.add_friend(luke);
luke.print();
susan.print();
laura.print();
alejandro.print();
}