A datastructure that accepts links, and emits them in an implementation-defined order.
The number of links in the queue.
If no links are in the queue.
Get (but not remove) the next link from the queue.
Get and remove the next link from the queue.
Add the given link to the queue.
A link.
The parent in which the given link was discovered.
If the link was added to the queue.
A datastructure that accepts links, and emits them in an implementation-defined order.