Macro moore::node_ref_group

macro_rules! node_ref_group {
    ($name:ident: $($var:ident($ty:ty),)+) => { ... };
    (MATCHES $value:expr, $($lhs:pat => $rhs:expr),+) => { ... };
}

Create a new group of node references.

This is a simple enum that contains variants for each of the references. Implements From for the various references, and Into<NodeId>.