components-arena

Strong-typed arena. Simple library for creating complex domain-specific self-referential data structures.

This arena does not use generations approach in a strict sense, but it uses some similar technique for avoiding the ABA effect.

Example: circular linked list

```rust use std::mem::replace; use macroattr2018::macroattr; use componentsarena::{Id, Arena, Component, ComponentClassMutex};

macro_attr! { #[derive(Component!)] struct Node { next: Id, data: (), } }

static NODE: ComponentClassMutex = ComponentClassMutex::new();

struct List { last: Option>, nodes: Arena, }

impl List { fn new() -> Self { List { last: None, nodes: Arena::new(&mut NODE.lock().unwrap()) } }

fn push(&mut self, data: ()) -> Id<Node> {
    let id = self.nodes.insert(|id| (Node { next: id, data }, id));
    if let Some(last) = self.last {
        self.nodes[id].next = replace(&mut self.nodes[last].next, id);
    } else {
        self.last = Some(id);
    }
    id
}

} ```