class Morph:
    def __init__(self, dc):
        self.surface = dc['surface']
        self.base = dc['base']
        self.pos = dc['pos']
        self.pos1 = dc['pos1']


class Chunk:
    def __init__(self, morphs, dst):
        self.morphs = morphs    # 形態素（Morphオブジェクト）のリスト
        self.dst = dst          # 係り先文節インデックス番号
        self.srcs = []          # 係り元文節インデックス番号のリスト


def parse_cabocha(block):
    def check_create_chunk(tmp):
        if len(tmp) > 0:
            c = Chunk(tmp, dst)
            res.append(c)
            tmp = []
        return tmp

    res = []
    tmp = []
    dst = None
    for line in block.split('\n'):
        if line == '':
            tmp = check_create_chunk(tmp)
        elif line[0] == '*':
            dst = line.split(' ')[2].rstrip('D')
            tmp = check_create_chunk(tmp)
        else:
            (surface, attr) = line.split('\t')
            attr = attr.split(',')
            lineDict = {
                'surface': surface,
                'base': attr[6],
                'pos': attr[0],
                'pos1': attr[1]
            }
            tmp.append(Morph(lineDict))

    for i, r in enumerate(res):
        res[int(r.dst)].srcs.append(i)
    return res


filename = 'ch05/ai.ja.txt.cabocha'
with open(filename, mode='rt', encoding='utf-8') as f:
    blocks = f.read().split('EOS\n')
blocks = list(filter(lambda x: x != '', blocks))
blocks = [parse_cabocha(block) for block in blocks]

for b in blocks:
    for m in b:
        if int(m.dst) > -1:
            print(''.join([mo.surface if mo.pos != '記号' else '' for mo in m.morphs]),
                  ''.join([mo.surface if mo.pos != '記号' else '' for mo in b[int(m.dst)].morphs]), sep='\t')
pythonを用いて、係り元の文節と係り先の文節のテキストをタブ区切り形式ですべて抽出せよ。ただし、句読点などの記号は出力しないようにせよ。