from typing import Dict, List, Optional, Tuple, Union from tokenizers import AddedToken, EncodeInput, Encoding, InputSequence, Tokenizer from tokenizers.decoders import Decoder from tokenizers.models import Model from tokenizers.normalizers import Normalizer from tokenizers.pre_tokenizers import PreTokenizer from tokenizers.processors import PostProcessor Offsets = Tuple[int, int] class BaseTokenizer: def __init__(self, tokenizer: Tokenizer, parameters=None): self._tokenizer = tokenizer self._parameters = parameters if parameters is not None else {} def __repr__(self): return "Tokenizer(vocabulary_size={}, {})".format( self._tokenizer.get_vocab_size(), ", ".join(k + "=" + str(v) for k, v in self._parameters.items()), ) def num_special_tokens_to_add(self, is_pair: bool) -> int: """ Return the number of special tokens that would be added for single/pair sentences. :param is_pair: Boolean indicating if the input would be a single sentence or a pair :return: """ return self._tokenizer.num_special_tokens_to_add(is_pair) def get_vocab(self, with_added_tokens: bool = True) -> Dict[str, int]: """Returns the vocabulary Args: with_added_tokens: boolean: Whether to include the added tokens in the vocabulary Returns: The vocabulary """ return self._tokenizer.get_vocab(with_added_tokens=with_added_tokens) def get_added_tokens_decoder(self) -> Dict[int, AddedToken]: """Returns the added reverse vocabulary Returns: The added vocabulary mapping ints to AddedTokens """ return self._tokenizer.get_added_tokens_decoder() def get_vocab_size(self, with_added_tokens: bool = True) -> int: """Return the size of vocabulary, with or without added tokens. Args: with_added_tokens: (`optional`) bool: Whether to count in added special tokens or not Returns: Size of vocabulary """ return self._tokenizer.get_vocab_size(with_added_tokens=with_added_tokens) def enable_padding( self, direction: Optional[str] = "right", pad_to_multiple_of: Optional[int] = None, pad_id: Optional[int] = 0, pad_type_id: Optional[int] = 0, pad_token: Optional[str] = "[PAD]", length: Optional[int] = None, ): """Change the padding strategy Args: direction: (`optional`) str: Can be one of: `right` or `left` pad_to_multiple_of: (`optional`) unsigned int: If specified, the padding length should always snap to the next multiple of the given value. For example if we were going to pad with a length of 250 but `pad_to_multiple_of=8` then we will pad to 256. pad_id: (`optional`) unsigned int: The indice to be used when padding pad_type_id: (`optional`) unsigned int: The type indice to be used when padding pad_token: (`optional`) str: The pad token to be used when padding length: (`optional`) unsigned int: If specified, the length at which to pad. If not specified we pad using the size of the longest sequence in a batch """ return self._tokenizer.enable_padding( direction=direction, pad_to_multiple_of=pad_to_multiple_of, pad_id=pad_id, pad_type_id=pad_type_id, pad_token=pad_token, length=length, ) def no_padding(self): """Disable padding""" return self._tokenizer.no_padding() @property def padding(self) -> Optional[dict]: """Get the current padding parameters Returns: None if padding is disabled, a dict with the currently set parameters if the padding is enabled. """ return self._tokenizer.padding def enable_truncation(self, max_length: int, stride: Optional[int] = 0, strategy: Optional[str] = "longest_first"): """Change the truncation options Args: max_length: unsigned int: The maximum length at which to truncate stride: (`optional`) unsigned int: The length of the previous first sequence to be included in the overflowing sequence strategy: (`optional`) str: Can be one of `longest_first`, `only_first` or `only_second` """ return self._tokenizer.enable_truncation(max_length, stride=stride, strategy=strategy) def no_truncation(self): """Disable truncation""" return self._tokenizer.no_truncation() @property def truncation(self) -> Optional[dict]: """Get the current truncation parameters Returns: None if truncation is disabled, a dict with the current truncation parameters if truncation is enabled """ return self._tokenizer.truncation def add_tokens(self, tokens: List[Union[str, AddedToken]]) -> int: """Add the given tokens to the vocabulary Args: tokens: List[Union[str, AddedToken]]: A list of tokens to add to the vocabulary. Each token can either be a string, or an instance of AddedToken Returns: The number of tokens that were added to the vocabulary """ return self._tokenizer.add_tokens(tokens) def add_special_tokens(self, special_tokens: List[Union[str, AddedToken]]) -> int: """Add the given special tokens to the vocabulary, and treat them as special tokens. The special tokens will never be processed by the model, and will be removed while decoding. Args: tokens: List[Union[str, AddedToken]]: A list of special tokens to add to the vocabulary. Each token can either be a string, or an instance of AddedToken Returns: The number of tokens that were added to the vocabulary """ return self._tokenizer.add_special_tokens(special_tokens) def normalize(self, sequence: str) -> str: """Normalize the given sequence Args: sequence: str: The sequence to normalize Returns: The normalized string """ return self._tokenizer.normalize(sequence) def encode( self, sequence: InputSequence, pair: Optional[InputSequence] = None, is_pretokenized: bool = False, add_special_tokens: bool = True, ) -> Encoding: """Encode the given sequence and pair. This method can process raw text sequences as well as already pre-tokenized sequences. Args: sequence: InputSequence: The sequence we want to encode. This sequence can be either raw text or pre-tokenized, according to the `is_pretokenized` argument: - If `is_pretokenized=False`: `InputSequence` is expected to be `str` - If `is_pretokenized=True`: `InputSequence` is expected to be `Union[List[str], Tuple[str]]` is_pretokenized: bool: Whether the input is already pre-tokenized. add_special_tokens: bool: Whether to add the special tokens while encoding. Returns: An Encoding """ if sequence is None: raise ValueError("encode: `sequence` can't be `None`") return self._tokenizer.encode(sequence, pair, is_pretokenized, add_special_tokens) def encode_batch( self, inputs: List[EncodeInput], is_pretokenized: bool = False, add_special_tokens: bool = True, ) -> List[Encoding]: """Encode the given inputs. This method accept both raw text sequences as well as already pre-tokenized sequences. Args: inputs: List[EncodeInput]: A list of single sequences or pair sequences to encode. Each `EncodeInput` is expected to be of the following form: `Union[InputSequence, Tuple[InputSequence, InputSequence]]` Each `InputSequence` can either be raw text or pre-tokenized, according to the `is_pretokenized` argument: - If `is_pretokenized=False`: `InputSequence` is expected to be `str` - If `is_pretokenized=True`: `InputSequence` is expected to be `Union[List[str], Tuple[str]]` is_pretokenized: bool: Whether the input is already pre-tokenized. add_special_tokens: bool: Whether to add the special tokens while encoding. Returns: A list of Encoding """ if inputs is None: raise ValueError("encode_batch: `inputs` can't be `None`") return self._tokenizer.encode_batch(inputs, is_pretokenized, add_special_tokens) def decode(self, ids: List[int], skip_special_tokens: Optional[bool] = True) -> str: """Decode the given list of ids to a string sequence Args: ids: List[unsigned int]: A list of ids to be decoded skip_special_tokens: (`optional`) boolean: Whether to remove all the special tokens from the output string Returns: The decoded string """ if ids is None: raise ValueError("None input is not valid. Should be a list of integers.") return self._tokenizer.decode(ids, skip_special_tokens=skip_special_tokens) def decode_batch(self, sequences: List[List[int]], skip_special_tokens: Optional[bool] = True) -> str: """Decode the list of sequences to a list of string sequences Args: sequences: List[List[unsigned int]]: A list of sequence of ids to be decoded skip_special_tokens: (`optional`) boolean: Whether to remove all the special tokens from the output strings Returns: A list of decoded strings """ if sequences is None: raise ValueError("None input is not valid. Should be list of list of integers.") return self._tokenizer.decode_batch(sequences, skip_special_tokens=skip_special_tokens) def token_to_id(self, token: str) -> Optional[int]: """Convert the given token to its corresponding id Args: token: str: The token to convert Returns: The corresponding id if it exists, None otherwise """ return self._tokenizer.token_to_id(token) def id_to_token(self, id: int) -> Optional[str]: """Convert the given token id to its corresponding string Args: token: id: The token id to convert Returns: The corresponding string if it exists, None otherwise """ return self._tokenizer.id_to_token(id) def save_model(self, directory: str, prefix: Optional[str] = None): """Save the current model to the given directory Args: directory: str: A path to the destination directory prefix: (Optional) str: An optional prefix, used to prefix each file name """ return self._tokenizer.model.save(directory, prefix=prefix) def save(self, path: str, pretty: bool = True): """Save the current Tokenizer at the given path Args: path: str: A path to the destination Tokenizer file """ return self._tokenizer.save(path, pretty) def to_str(self, pretty: bool = False): """Get a serialized JSON version of the Tokenizer as a str Args: pretty: bool: Whether the JSON string should be prettified Returns: str """ return self._tokenizer.to_str(pretty) def post_process( self, encoding: Encoding, pair: Optional[Encoding] = None, add_special_tokens: bool = True ) -> Encoding: """Apply all the post-processing steps to the given encodings. The various steps are: 1. Truncate according to global params (provided to `enable_truncation`) 2. Apply the PostProcessor 3. Pad according to global params. (provided to `enable_padding`) Args: encoding: Encoding: The main Encoding to post process pair: Optional[Encoding]: An optional pair Encoding add_special_tokens: bool: Whether to add special tokens Returns: The resulting Encoding """ return self._tokenizer.post_process(encoding, pair, add_special_tokens) @property def model(self) -> Model: return self._tokenizer.model @model.setter def model(self, model: Model): self._tokenizer.model = model @property def normalizer(self) -> Normalizer: return self._tokenizer.normalizer @normalizer.setter def normalizer(self, normalizer: Normalizer): self._tokenizer.normalizer = normalizer @property def pre_tokenizer(self) -> PreTokenizer: return self._tokenizer.pre_tokenizer @pre_tokenizer.setter def pre_tokenizer(self, pre_tokenizer: PreTokenizer): self._tokenizer.pre_tokenizer = pre_tokenizer @property def post_processor(self) -> PostProcessor: return self._tokenizer.post_processor @post_processor.setter def post_processor(self, post_processor: PostProcessor): self._tokenizer.post_processor = post_processor @property def decoder(self) -> Decoder: return self._tokenizer.decoder @decoder.setter def decoder(self, decoder: Decoder): self._tokenizer.decoder = decoder