Adding pretty print of tokenizer

[haixuanTao]

Adding a default implementation for __str__ and __repr__ for Tokenizer.

Test it out

Before

>>> from tokenizers import Tokenizer, decoders, models, normalizers, pre_tokenizers, processors
>>> from tokenizers.implementations import BaseTokenizer
>>> toki = Tokenizer(models.BPE())
>>> print(toki)
<tokenizers.Tokenizer object at 0x7d687d32bc30>

After

>>> from tokenizers import Tokenizer, decoders, models, normalizers, pre_tokenizers, processors
>>> from tokenizers.implementations import BaseTokenizer
>>> toki = Tokenizer(models.BPE())
>>> print(toki)
TokenizerImpl {
    normalizer: None,
    pre_tokenizer: None,
    model: PyModel {
        model: RwLock {
            data: BPE(
                BPE {
                    dropout: None,
                    unk_token: None,
                    continuing_subword_prefix: None,
                    end_of_word_suffix: None,
                    fuse_unk: false,
                    byte_fallback: false,
                    vocab: 0,
                    merges: 0,
                    ignore_merges: false,
                },
            ),
            poisoned: false,
            ..
        },
    },
    post_processor: None,
    decoder: None,
    added_vocabulary: AddedVocabulary {
        added_tokens_map: {},
        added_tokens_map_r: {},
        added_tokens: [],
        special_tokens: [],
        special_tokens_set: {},
        split_trie: (
            AhoCorasick(
                dfa::DFA(
                D 000000: \x00 => 0
                F 000001:
                 >000002: \x00 => 2
                  000003: \x00 => 0
                match kind: LeftmostLongest
                prefilter: false
                state length: 4
                pattern length: 0
                shortest pattern length: 18446744073709551615
                longest pattern length: 0
                alphabet length: 1
                stride: 1
                byte classes: ByteClasses(0 => [0-255])
                memory usage: 16
                )
                ,
            ),
            [],
        ),
        split_normalized_trie: (
            AhoCorasick(
                dfa::DFA(
                D 000000: \x00 => 0
                F 000001:
                 >000002: \x00 => 2
                  000003: \x00 => 0
                match kind: LeftmostLongest
                prefilter: false
                state length: 4
                pattern length: 0
                shortest pattern length: 18446744073709551615
                longest pattern length: 0
                alphabet length: 1
                stride: 1
                byte classes: ByteClasses(0 => [0-255])
                memory usage: 16
                )
                ,
            ),
            [],
        ),
        encode_special_tokens: false,
    },
    truncation: None,
    padding: None,
}

Hope this helps :)

Open for any critics and the representation or implementation

Inspired by https://github.com/dora-rs/dora/pull/503

[HuggingFaceDocBuilderDev]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

[ArthurZucker]

Closing in favor of #1542!