reduce with midstate preserved

midreduce.py

def midreduce_iter(func, d, init=None):
  it = iter(d)
  if init is None:
    i = it.next()
    yield i
  else:
    i = init
  while True:
    i = func(i, it.next()) # as it will raise StopIteration exception...
    yield i

# reduce with midstate preserved
# midreduce(lambda x,y: x+y, [1] * 8) = [1,2,3,4,5,6,7,8]
def midreduce(func, d, init=None):
  return list(midreduce_iter(func, d, init))