# coding=utf-8
# Copyright 2018 The Google AI Language Team Authors and The HuggingFace Inc. team.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Tokenization classes."""
import collections
import copy
import os
import unicodedata
from typing import Optional
from ...utils import logging
from ..bert.tokenization_bert import BasicTokenizer, BertTokenizer, WordpieceTokenizer, load_vocab
logger = logging.get_logger(__name__)
VOCAB_FILES_NAMES = {"vocab_file": "vocab.txt"}
PRETRAINED_VOCAB_FILES_MAP = {
"vocab_file": {
"cl-tohoku/bert-base-japanese": "https://huggingface.co/cl-tohoku/bert-base-japanese/resolve/main/vocab.txt",
"cl-tohoku/bert-base-japanese-whole-word-masking": "https://huggingface.co/cl-tohoku/bert-base-japanese-whole-word-masking/resolve/main/vocab.txt",
"cl-tohoku/bert-base-japanese-char": "https://huggingface.co/cl-tohoku/bert-base-japanese-char/resolve/main/vocab.txt",
"cl-tohoku/bert-base-japanese-char-whole-word-masking": "https://huggingface.co/cl-tohoku/bert-base-japanese-char-whole-word-masking/resolve/main/vocab.txt",
}
}
PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES = {
"cl-tohoku/bert-base-japanese": 512,
"cl-tohoku/bert-base-japanese-whole-word-masking": 512,
"cl-tohoku/bert-base-japanese-char": 512,
"cl-tohoku/bert-base-japanese-char-whole-word-masking": 512,
}
PRETRAINED_INIT_CONFIGURATION = {
"cl-tohoku/bert-base-japanese": {
"do_lower_case": False,
"word_tokenizer_type": "mecab",
"subword_tokenizer_type": "wordpiece",
},
"cl-tohoku/bert-base-japanese-whole-word-masking": {
"do_lower_case": False,
"word_tokenizer_type": "mecab",
"subword_tokenizer_type": "wordpiece",
},
"cl-tohoku/bert-base-japanese-char": {
"do_lower_case": False,
"word_tokenizer_type": "mecab",
"subword_tokenizer_type": "character",
},
"cl-tohoku/bert-base-japanese-char-whole-word-masking": {
"do_lower_case": False,
"word_tokenizer_type": "mecab",
"subword_tokenizer_type": "character",
},
}
[docs]class BertJapaneseTokenizer(BertTokenizer):
r"""
Construct a BERT tokenizer for Japanese text, based on a MecabTokenizer.
Args:
vocab_file (:obj:`str`):
Path to a one-wordpiece-per-line vocabulary file.
do_lower_case (:obj:`bool`, `optional`, defaults to :obj:`True`):
Whether to lower case the input. Only has an effect when do_basic_tokenize=True.
do_word_tokenize (:obj:`bool`, `optional`, defaults to :obj:`True`):
Whether to do word tokenization.
do_subword_tokenize (:obj:`bool`, `optional`, defaults to :obj:`True`):
Whether to do subword tokenization.
word_tokenizer_type (:obj:`str`, `optional`, defaults to :obj:`"basic"`):
Type of word tokenizer.
subword_tokenizer_type (:obj:`str`, `optional`, defaults to :obj:`"wordpiece"`):
Type of subword tokenizer.
mecab_kwargs (:obj:`str`, `optional`):
Dictionary passed to the :obj:`MecabTokenizer` constructor.
"""
vocab_files_names = VOCAB_FILES_NAMES
pretrained_vocab_files_map = PRETRAINED_VOCAB_FILES_MAP
pretrained_init_configuration = PRETRAINED_INIT_CONFIGURATION
max_model_input_sizes = PRETRAINED_POSITIONAL_EMBEDDINGS_SIZES
def __init__(
self,
vocab_file,
do_lower_case=False,
do_word_tokenize=True,
do_subword_tokenize=True,
word_tokenizer_type="basic",
subword_tokenizer_type="wordpiece",
never_split=None,
unk_token="[UNK]",
sep_token="[SEP]",
pad_token="[PAD]",
cls_token="[CLS]",
mask_token="[MASK]",
mecab_kwargs=None,
**kwargs
):
super(BertTokenizer, self).__init__(
unk_token=unk_token,
sep_token=sep_token,
pad_token=pad_token,
cls_token=cls_token,
mask_token=mask_token,
do_lower_case=do_lower_case,
do_word_tokenize=do_word_tokenize,
do_subword_tokenize=do_subword_tokenize,
word_tokenizer_type=word_tokenizer_type,
subword_tokenizer_type=subword_tokenizer_type,
never_split=never_split,
mecab_kwargs=mecab_kwargs,
**kwargs,
)
# ^^ We call the grandparent's init, not the parent's.
if not os.path.isfile(vocab_file):
raise ValueError(
f"Can't find a vocabulary file at path '{vocab_file}'. To load the vocabulary from a Google pretrained "
"model use `tokenizer = BertTokenizer.from_pretrained(PRETRAINED_MODEL_NAME)`"
)
self.vocab = load_vocab(vocab_file)
self.ids_to_tokens = collections.OrderedDict([(ids, tok) for tok, ids in self.vocab.items()])
self.do_word_tokenize = do_word_tokenize
self.word_tokenizer_type = word_tokenizer_type
self.lower_case = do_lower_case
self.never_split = never_split
self.mecab_kwargs = copy.deepcopy(mecab_kwargs)
if do_word_tokenize:
if word_tokenizer_type == "basic":
self.word_tokenizer = BasicTokenizer(
do_lower_case=do_lower_case, never_split=never_split, tokenize_chinese_chars=False
)
elif word_tokenizer_type == "mecab":
self.word_tokenizer = MecabTokenizer(
do_lower_case=do_lower_case, never_split=never_split, **(mecab_kwargs or {})
)
else:
raise ValueError(f"Invalid word_tokenizer_type '{word_tokenizer_type}' is specified.")
self.do_subword_tokenize = do_subword_tokenize
self.subword_tokenizer_type = subword_tokenizer_type
if do_subword_tokenize:
if subword_tokenizer_type == "wordpiece":
self.subword_tokenizer = WordpieceTokenizer(vocab=self.vocab, unk_token=self.unk_token)
elif subword_tokenizer_type == "character":
self.subword_tokenizer = CharacterTokenizer(vocab=self.vocab, unk_token=self.unk_token)
else:
raise ValueError(f"Invalid subword_tokenizer_type '{subword_tokenizer_type}' is specified.")
@property
def do_lower_case(self):
return self.lower_case
def __getstate__(self):
state = dict(self.__dict__)
if self.word_tokenizer_type == "mecab":
del state["word_tokenizer"]
return state
def __setstate__(self, state):
self.__dict__ = state
if self.word_tokenizer_type == "mecab":
self.word_tokenizer = MecabTokenizer(
do_lower_case=self.do_lower_case, never_split=self.never_split, **(self.mecab_kwargs or {})
)
def _tokenize(self, text):
if self.do_word_tokenize:
tokens = self.word_tokenizer.tokenize(text, never_split=self.all_special_tokens)
else:
tokens = [text]
if self.do_subword_tokenize:
split_tokens = [sub_token for token in tokens for sub_token in self.subword_tokenizer.tokenize(token)]
else:
split_tokens = tokens
return split_tokens
class MecabTokenizer:
"""Runs basic tokenization with MeCab morphological parser."""
def __init__(
self,
do_lower_case=False,
never_split=None,
normalize_text=True,
mecab_dic: Optional[str] = "ipadic",
mecab_option: Optional[str] = None,
):
"""
Constructs a MecabTokenizer.
Args:
**do_lower_case**: (`optional`) boolean (default True)
Whether to lowercase the input.
**never_split**: (`optional`) list of str
Kept for backward compatibility purposes. Now implemented directly at the base class level (see
:func:`PreTrainedTokenizer.tokenize`) List of tokens not to split.
**normalize_text**: (`optional`) boolean (default True)
Whether to apply unicode normalization to text before tokenization.
**mecab_dic**: (`optional`) string (default "ipadic")
Name of dictionary to be used for MeCab initialization. If you are using a system-installed dictionary,
set this option to `None` and modify `mecab_option`.
**mecab_option**: (`optional`) string
String passed to MeCab constructor.
"""
self.do_lower_case = do_lower_case
self.never_split = never_split if never_split is not None else []
self.normalize_text = normalize_text
try:
import fugashi
except ModuleNotFoundError as error:
raise error.__class__(
"You need to install fugashi to use MecabTokenizer. "
"See https://pypi.org/project/fugashi/ for installation."
)
mecab_option = mecab_option or ""
if mecab_dic is not None:
if mecab_dic == "ipadic":
try:
import ipadic
except ModuleNotFoundError as error:
raise error.__class__(
"The ipadic dictionary is not installed. "
"See https://github.com/polm/ipadic-py for installation."
)
dic_dir = ipadic.DICDIR
elif mecab_dic == "unidic_lite":
try:
import unidic_lite
except ModuleNotFoundError as error:
raise error.__class__(
"The unidic_lite dictionary is not installed. "
"See https://github.com/polm/unidic-lite for installation."
)
dic_dir = unidic_lite.DICDIR
elif mecab_dic == "unidic":
try:
import unidic
except ModuleNotFoundError as error:
raise error.__class__(
"The unidic dictionary is not installed. "
"See https://github.com/polm/unidic-py for installation."
)
dic_dir = unidic.DICDIR
if not os.path.isdir(dic_dir):
raise RuntimeError(
"The unidic dictionary itself is not found."
"See https://github.com/polm/unidic-py for installation."
)
else:
raise ValueError("Invalid mecab_dic is specified.")
mecabrc = os.path.join(dic_dir, "mecabrc")
mecab_option = f'-d "{dic_dir}" -r "{mecabrc}" ' + mecab_option
self.mecab = fugashi.GenericTagger(mecab_option)
def tokenize(self, text, never_split=None, **kwargs):
"""Tokenizes a piece of text."""
if self.normalize_text:
text = unicodedata.normalize("NFKC", text)
never_split = self.never_split + (never_split if never_split is not None else [])
tokens = []
for word in self.mecab(text):
token = word.surface
if self.do_lower_case and token not in never_split:
token = token.lower()
tokens.append(token)
return tokens
class CharacterTokenizer:
"""Runs Character tokenization."""
def __init__(self, vocab, unk_token, normalize_text=True):
"""
Constructs a CharacterTokenizer.
Args:
**vocab**:
Vocabulary object.
**unk_token**: str
A special symbol for out-of-vocabulary token.
**normalize_text**: (`optional`) boolean (default True)
Whether to apply unicode normalization to text before tokenization.
"""
self.vocab = vocab
self.unk_token = unk_token
self.normalize_text = normalize_text
def tokenize(self, text):
"""
Tokenizes a piece of text into characters.
For example, :obj:`input = "apple""` wil return as output :obj:`["a", "p", "p", "l", "e"]`.
Args:
text: A single token or whitespace separated tokens.
This should have already been passed through `BasicTokenizer`.
Returns:
A list of characters.
"""
if self.normalize_text:
text = unicodedata.normalize("NFKC", text)
output_tokens = []
for char in text:
if char not in self.vocab:
output_tokens.append(self.unk_token)
continue
output_tokens.append(char)
return output_tokens