Trait InnerNode

pub trait InnerNode<E: Edge>:
    Sized
    + Eq
    + Hash
    + DropWith<E> {
    type ChildrenIter<'a>: ExactSizeIterator<Item = Borrowed<'a, E>>
       where Self: 'a,
             E: 'a;

    const ARITY: usize;

    // Required methods
    fn new(level: LevelNo, children: impl IntoIterator<Item = E>) -> Self;
    fn check_level(&self, check: impl FnOnce(LevelNo) -> bool) -> bool;
    fn assert_level_matches(&self, level: LevelNo);
    fn children(&self) -> Self::ChildrenIter<'_>;
    fn child(&self, n: usize) -> Borrowed<'_, E>;
    unsafe fn set_child(&self, n: usize, child: E) -> E;
    fn ref_count(&self) -> usize;
}

Node in a decision diagram

Eq and Hash should consider the children only, in particular no level information. This means that if Self implements HasLevel, HasLevel::set_level() may be called while the node is present in a LevelView. This is not the case for InnerNode::set_child(): The user must remove the node from the LevelView before setting the children (and re-insert it afterwards).

Required Associated Constants

const ARITY: usize

The node’s arity (upper bound)

Required Associated Types

type ChildrenIter<'a>: ExactSizeIterator<Item = Borrowed<'a, E>> where Self: 'a, E: 'a

Iterator over children of an inner node

Required Methods

fn new(level: LevelNo, children: impl IntoIterator<Item = E>) -> Self

Create a new node

Note that this does not apply any reduction rules. A node type that does not store levels internally (does not implement HasLevel) may simply ignore the level parameter.

Panics if children’s length does not match the node’s requirements (typically, the length should be Self::ARITY, but some node types may deviate from that).

fn check_level(&self, check: impl FnOnce(LevelNo) -> bool) -> bool

Returns the result of check applied to the node’s level in case this node type stores levels, otherwise returns true.

Use HasLevel::level() if you require your nodes to store the level number and want to get the level number.

fn assert_level_matches(&self, level: LevelNo)

Panics if the node types stores a level and the node’s level is not level

fn children(&self) -> Self::ChildrenIter<'_>

Get the children of this node as an iterator

fn child(&self, n: usize) -> Borrowed<'_, E>

Get the n-th child of this node

unsafe fn set_child(&self, n: usize, child: E) -> E

Set the n-th child of this node

Returns the previous n-th child.

Note that this function may also change the node’s hash value etc., so in case the node is stored in a hash table (LevelView), it needs to be removed before calling this method.

Panics if the node does not have an n-th child.

Safety

The caller must have exclusive access to the node. In the first place, this is granted by acquiring an exclusive manager lock (Function::with_manager_exclusive() or ManagerRef::with_manager_exclusive()). However, exclusive access to some nodes may be delegated to other threads (which is the reason why we only require a shared and not a mutable manager reference). Furthermore, there must not be a borrowed child (obtained via InnerNode::children()).

fn ref_count(&self) -> usize

Get the node’s reference count

This ignores all internal references used by the manager implementation.

Object Safety

This trait is not object safe.

Implementors