||A SpaceStrippedDocument represents a view of a real Document in which selected
whitespace text nodes are treated as having been stripped.
||A StrippedNode is a view of a node, in a virtual tree that has whitespace
text nodes stripped from it.
||A TypeStrippedDocument represents a view of a real Document in which all nodes are
||A TypeStrippedNode is a view of a node, in a virtual tree that has type
annotations stripped from it.
||This class represents a node that is a virtual copy of another node: that is, it behaves as a node that's the
same as another node, but has different identity.
||A virtual copy of a document node
||This class represents a virtual copy of a node with type annotations stripped