Implement a tree iterator without using a stack

treeiterator.py

def eachnode(tree, n=0):
    if n == len(tree):
        raise StopIteration
    yield tree[n] ## The method of access is specific to the data structure
    for subnode in eachnode(tree, n+1):
        yield subnode

if __name__ == '__main__':

    tree = [10,20,30] ## Assuming array for test purposes, can be a real tree.

    for node in eachnode(tree):
        print node