rs-intrusive - Support macros for building intrusive data structures

in Rust.

An intrusive structure is a general-purpose structure directly embedded within a containing structure, in order to add that general-purpose facility to the container. As an example, one might use an intrusive "link" structure to allow objects to be organized in a linked-list:

struct Link {
    next: Option<Link>,
}
struct List {
    head: Option<Link>,
    tail: Option<Link>,
}

struct Container {
    link: Link,
}

While this module does not provide a linked-list implementation (for separation-of-concerns reasons, I believe a linked-list implementation belongs in a separate crate), it does provide some necessary abstractions for using intrusive structures:

• The field_offset! macro, which identifies the location of a field in a containing structure. This isn't too useful in itself, but is necessary to support:
• The intrusive! macro, which provides a newtype for using "intrusive" fields to work with the container object.

Usage

#[macro_use(intrusive)]
extern crate "intrusive";

struct Link {
    next: Option<Link>,
}
// FIXME: is this legal? want to enforce constraint that `List` only
// operates against intrusive `Link`s.
struct<T> List<T> where
    T: Intrusive<Link>,
    T::Field: Link,
{
    head: Option<LinkType>,
}

struct Container {
    link: Link,
}
intrusive!(ContainerLink = Container:link::Link);

fn create() -> List<ContainerLink> {
    let x = Box::new(Container { link: None });
    let link: ContainerLink = intrusive::Intrusive::move_from(x);
    List<ContainerLink> { head: Some(link) }
}
fn head(list: List<ContainerLink>) -> Box<Container> {
    list.head.unwrap().container_of()
}

Contributing

1. Fork it ( https://github.com/aidancully/rs-intrusive/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request