["Followup-To:" header set to comp.lang.python.] On Wed, 18 May 2011 22:40:28 +0200, Raymond Wiker <raw@RAWMBP-2.local> wrote: : I said tree operations, not tree walks. A tree operation might : involve several tree walks.
OK. The original claim under dispute regarded tree walks. : Further, there has been an implicit : assumption (I think) in this discussion that the order of children is : given, or does not matter - if this is not the case, then you also need : to maintain a stack of data structures representing lists (or sets) of : children. It assumes that there is some canonical ordering on the children. If the tree nodes store their children as sets, where the implementation does not guarantee that they can be retrieved in the same order every time, then it breaks. However, that would be an unusual implementation. The tree has to store the children for each node, one way or another. The only thing I am assuming is that the children can be inspected in the same order every time the node is visited. -- :-- Hans Georg -- http://mail.python.org/mailman/listinfo/python-list
