gistfile1.py

IN, OUT = object(), object()

def parse(raw):
    state = OUT
    parsed = []
    count = 0
    
    for c in raw:
        if c == '(':
            if state is OUT:
                cur = []
                state = IN
            count += 1
            continue
        elif c == ')' and state is IN:
            if count == 1:
                parsed.append(''.join(cur))
                state = OUT
            count -= 1
        elif state is IN:
            cur.append(c)
    return parsed


def test():
    cases = ['(a, b, c)(e, f)(g, i, j, k)',
             '(a (b) c),(e, f)((g, i), j, k)']
    for c in cases:
        print parse(c)

test()
# ['a, b, c', 'e, f', 'g, i, j, k']
# ['a b c', 'e, f', 'g, i, j, k']