Update positions of empty nodes when regular nodes are shifted.

Author: dan-zeman

udapi/core/node.py

@@ -574,6 +574,7 @@ def remove(self, children=None):
     def _shift_before_ord(self, reference_ord, without_children=False):
         """Internal method for changing word order."""
         all_nodes = self._root._descendants
+        empty_nodes = self._root.empty_nodes
 
         # Moving a single node can be faster than nodes_to_move = [self]
         if without_children or not self._children:
@@ -584,14 +585,22 @@ def _shift_before_ord(self, reference_ord, without_children=False):
                     all_nodes[i_ord - 1]._ord = i_ord
                 all_nodes[reference_ord - 2] = self
                 self._ord = reference_ord - 1
+                for en in empty_nodes:
+                    if en._ord > my_ord and en._ord < reference_ord:
+                        en._ord -= 1
             elif reference_ord < my_ord:
                 for i_ord in range(my_ord, reference_ord, -1):
                     all_nodes[i_ord - 1] = all_nodes[i_ord - 2]
                     all_nodes[i_ord - 1]._ord = i_ord
                 all_nodes[reference_ord - 1] = self
                 self._ord = reference_ord
+                for en in empty_nodes:
+                    ###!!! Empty nodes before the first overt token (ID=0.X) will be never moved this way. We cannot know whether the caller wanted to place the shifted node before or after them.
+                    if en._ord < my_ord and en._ord > reference_ord:
+                        en._ord += 1
             return
 
+        ###!!! Updating ords of empty nodes is implemented for the simple case above but it has to be implemented also for the complex case below!
         nodes_to_move = self.descendants(add_self=True)
         first_ord, last_ord = nodes_to_move[0]._ord, nodes_to_move[-1]._ord