I'd like to use a QTreeView to display/edit a directed acyclic graph (a tree where a node may have more than one parent). For example, the following tree has node2 used in 2 different places:
Qt Code: 
  1. Root
  2.   parentA
  3.     node1
  4.     node2
  5.   parentB
  6.     node2
  7.     node3
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The only challenge is implementing the "parent()" method. At the moment there is no way to know the path that was taken to get to a node so that the proper parent can be returned based upon how the node was reached. At the moment, I am thinking of sub-classing QModelIndex (ugh) to extend it with the full path to the object.

Has anyone else done anything like this? How did you do it?