Select interface (look ma, no macros!)

gistfile1.rs

/// A Select is a merge of multiple Receivers; you wait on a Select
/// and it blocks until any one of the attached Receivers sees
/// something.
struct Select<T>;

/// Identifier for Receivers attached to a Select
type RecvId = uint;

impl<T:Default> Select<T> {
  /// Creates a new `Select` which receives objects of type `T`
  fn new() -> Select<T>;

  /// Adds a `Receiver` to the `Select`. Notice that this takes the `Receiver`;
  /// `Receiver` implements `Clone` so this is no inconvienience to the user.
  /// Returns an ID which can be used to remove the `Receiver`.
  fn add<U>(&mut self, rx: Receiver<U>, callback: |U| -> T) -> RecvId;

  /// Removes a `Reciever` with the given `id` from the `Select`.
  fn remove(&mut self, id: RecvId);

  /// Blocks until one of the contained receivers is ready to receive. Then
  /// receive that data, call the corresponding callback, and return whatever
  /// the callback does.
  fn recv(&mut self) -> T {};
}