The root of the tree may be deleted with this method. If this node has no sons, tree<-root will be set to @nil. Otherwise the first son of this node will be made the new root of the tree.

When the tree<-display_root is deleted, it is set to the first parent of this node.

Bugs: Deleting the root of a tree that has multiple sons is not well defined.

See also

- node->unlink
- node->delete_tree