complex_itermerge.py

import itertools

def complex_itermerge(compare, *iters):
    _i = [iter(i) for i in iters]
    backlog = []
    for _i_vals in itertools.izip(*_i):
        assoc = zip(_i, _i_vals)
        state_length = len(assoc)
        for i in range(0, state_length):
            lhs = assoc[i]
            we_are_true = True

            other_values = []
            for j in range(0, state_length):
                if i == j:
                    continue
                we_are_true = we_are_true and compare(lhs[1], assoc[j][1])
                other_values.append(assoc[j][1])
            if we_are_true:
                for_removal = []
                for item in backlog:
                    if compare(item, lhs[1]):
                        yield item
                        for_removal.append(item)
                for item in for_removal:
                    backlog.remove(item)
                yield lhs[1]
                backlog = backlog + other_values
    for iterator in _i:
        for _i_val in iterator:
            for_removal = []
            for item in backlog:
                if compare(item, _i_val):
                    yield item
                    for_removal.append(item)
            for item in for_removal:
                backlog.remove(item)
            yield _i_val
    for value in backlog:
        yield value
    raise StopIteration