juman.py

import os
from transformers import AlbertTokenizerFast
from transformers.models.bert_japanese.tokenization_bert_japanese import MecabTokenizer
try:
  from transformers.utils import cached_file
except:
  from transformers.file_utils import cached_path,hf_bucket_url
  cached_file=lambda x,y:os.path.join(x,y) if os.path.isdir(x) else cached_path(hf_bucket_url(x,y))

class MecabPreTokenizer(MecabTokenizer):
  def mecab_split(self,i,normalized_string):
    t=str(normalized_string)
    z=[]
    e=0
    for c in self.tokenize(t):
      s=t.find(c,e)
      e=e if s<0 else s+len(c)
      z.append((0,0) if s<0 else (s,e))
    return [normalized_string[s:e] for s,e in z if e>0]
  def pre_tokenize(self,pretok):
    pretok.split(self.mecab_split)

class JumanAlbertTokenizerFast(AlbertTokenizerFast):
  def __init__(self,**kwargs):
    from tokenizers.pre_tokenizers import PreTokenizer,Metaspace,Sequence
    super().__init__(**kwargs)
    d,r="/var/lib/mecab/dic/juman-utf8","/etc/mecabrc"
    if not (os.path.isdir(d) and os.path.isfile(r)):
      import zipfile
      import tempfile
      self.dicdir=tempfile.TemporaryDirectory()
      d=self.dicdir.name
      with zipfile.ZipFile(cached_file(self.name_or_path,"mecab-jumandic-utf8.zip")) as z:
        z.extractall(d)
      r=os.path.join(d,"mecabrc")
      with open(r,"w",encoding="utf-8") as w:
        print("dicdir =",d,file=w)
    self.custom_pre_tokenizer=Sequence([PreTokenizer.custom(MecabPreTokenizer(mecab_dic=None,mecab_option="-d "+d+" -r "+r)),Metaspace()])
    self._tokenizer.pre_tokenizer=self.custom_pre_tokenizer
  def save_pretrained(self,save_directory,**kwargs):
    import shutil
    from tokenizers.pre_tokenizers import Metaspace
    self._auto_map={"AutoTokenizer":[None,"juman.JumanAlbertTokenizerFast"]}
    self._tokenizer.pre_tokenizer=Metaspace()
    super().save_pretrained(save_directory,**kwargs)
    self._tokenizer.pre_tokenizer=self.custom_pre_tokenizer
    shutil.copy(os.path.abspath(__file__),os.path.join(save_directory,"juman.py"))
    shutil.copy(cached_file(self.name_or_path,"mecab-jumandic-utf8.zip"),os.path.join(save_directory,"mecab-jumandic-utf8.zip"))