nodes2.py

nodes2.py

class Leaf:
    def __init__(self, val):
        self.val = val

    def values(self):
        # Following two lines for debugging.
        # So that we can see how many stack frames there
        # are at the deepest level while traversing the tree.
        import traceback; traceback.print_stack()
        import sys; sys.exit(0)

        yield self.val


class Node:
    def __init__(self, children):
        self.children = children

    def values(self):
        for c in self.children:
            yield from c.values()

    def value(self):
        return sum(self.values())


data = Node([
          Node([
              Node([
                  Node([
                      Leaf(1),
                      Leaf(2),
                      Leaf(3),
                  ]),
                  Node([
                      Leaf(4),
                      Leaf(5),
                      Leaf(6),
                  ]),
              ]),
              Node([
                  Node([
                      Leaf(7),
                      Leaf(8),
                      Leaf(9),
                  ]),
                  Node([
                      Leaf(10),
                      Leaf(11),
                      Leaf(12),
                  ]),
              ])
          ])
      ])


data.value()

# Output:
"""
  File "/tmp/nodes.py", line 58, in <module>
    data.value()
  File "/tmp/nodes.py", line 25, in value
    return sum(self.values())
  File "/tmp/nodes.py", line 22, in values
    yield from c.values()
  File "/tmp/nodes.py", line 22, in values
    yield from c.values()
  File "/tmp/nodes.py", line 22, in values
    yield from c.values()
  File "/tmp/nodes.py", line 10, in values
    import traceback; traceback.print_stack()
"""