Implement __new__ for PreTokenizers

__new__ allows PreTokenizers to be instansiated through the python
constructor.

bindings/python/src/pre_tokenizers.rs

@@ -26,13 +26,13 @@ impl PreTokenizer {
     }
 }
 
-#[pyclass]
+#[pyclass(extends=PreTokenizer)]
 pub struct ByteLevel {}
 #[pymethods]
 impl ByteLevel {
-    #[staticmethod]
+    #[new]
     #[args(kwargs = "**")]
-    fn new(kwargs: Option<&PyDict>) -> PyResult<PreTokenizer> {
+    fn new(obj: &PyRawObject, kwargs: Option<&PyDict>) -> PyResult<()> {
         let mut add_prefix_space = true;
 
         if let Some(kwargs) = kwargs {
@@ -45,11 +45,11 @@ impl ByteLevel {
             }
         }
 
-        Ok(PreTokenizer {
+        Ok(obj.init(PreTokenizer {
             pretok: Container::Owned(Box::new(tk::pre_tokenizers::byte_level::ByteLevel::new(
                 add_prefix_space,
             ))),
-        })
+        }))
     }
 
     #[staticmethod]
@@ -61,66 +61,66 @@ impl ByteLevel {
     }
 }
 
-#[pyclass]
+#[pyclass(extends=PreTokenizer)]
 pub struct Whitespace {}
 #[pymethods]
 impl Whitespace {
-    #[staticmethod]
-    fn new() -> PyResult<PreTokenizer> {
-        Ok(PreTokenizer {
+    #[new]
+    fn new(obj: &PyRawObject) -> PyResult<()> {
+        Ok(obj.init(PreTokenizer {
             pretok: Container::Owned(Box::new(tk::pre_tokenizers::whitespace::Whitespace)),
-        })
+        }))
     }
 }
 
-#[pyclass]
+#[pyclass(extends=PreTokenizer)]
 pub struct WhitespaceSplit {}
 #[pymethods]
 impl WhitespaceSplit {
-    #[staticmethod]
-    fn new() -> PyResult<PreTokenizer> {
-        Ok(PreTokenizer {
+    #[new]
+    fn new(obj: &PyRawObject) -> PyResult<()> {
+        Ok(obj.init(PreTokenizer {
             pretok: Container::Owned(Box::new(tk::pre_tokenizers::whitespace::WhitespaceSplit)),
-        })
+        }))
     }
 }
 
-#[pyclass]
+#[pyclass(extends=PreTokenizer)]
 pub struct CharDelimiterSplit {}
 #[pymethods]
 impl CharDelimiterSplit {
-    #[staticmethod]
-    pub fn new(delimiter: &str) -> PyResult<PreTokenizer> {
+    #[new]
+    pub fn new(obj: &PyRawObject, delimiter: &str) -> PyResult<()> {
         let chr_delimiter = delimiter.chars().nth(0).ok_or(exceptions::Exception::py_err(
             "delimiter must be a single character",
         ))?;
-        Ok(PreTokenizer{
+        Ok(obj.init(PreTokenizer{
             pretok:Container::Owned(Box::new(
                 tk::pre_tokenizers::delimiter::CharDelimiterSplit::new(chr_delimiter)
             ))
-        })
+        }))
     }
 }
 
-#[pyclass]
+#[pyclass(extends=PreTokenizer)]
 pub struct BertPreTokenizer {}
 #[pymethods]
 impl BertPreTokenizer {
-    #[staticmethod]
-    fn new() -> PyResult<PreTokenizer> {
-        Ok(PreTokenizer {
+    #[new]
+    fn new(obj: &PyRawObject) -> PyResult<()> {
+        Ok(obj.init(PreTokenizer {
             pretok: Container::Owned(Box::new(tk::pre_tokenizers::bert::BertPreTokenizer)),
-        })
+        }))
     }
 }
 
-#[pyclass]
+#[pyclass(extends=PreTokenizer)]
 pub struct Metaspace {}
 #[pymethods]
 impl Metaspace {
-    #[staticmethod]
+    #[new]
     #[args(kwargs = "**")]
-    fn new(kwargs: Option<&PyDict>) -> PyResult<PreTokenizer> {
+    fn new(obj: &PyRawObject, kwargs: Option<&PyDict>) -> PyResult<()> {
         let mut replacement = '▁';
         let mut add_prefix_space = true;
 
@@ -140,12 +140,12 @@ impl Metaspace {
             }
         }
 
-        Ok(PreTokenizer {
+        Ok(obj.init(PreTokenizer {
             pretok: Container::Owned(Box::new(tk::pre_tokenizers::metaspace::Metaspace::new(
                 replacement,
                 add_prefix_space,
             ))),
-        })
+        }))
     }
 }
 

bindings/python/tokenizers/implementations/bert_wordpiece.py

@@ -37,7 +37,7 @@ class BertWordPieceTokenizer(BaseTokenizer):
             strip_accents=strip_accents,
             lowercase=lowercase,
         )
-        tokenizer.pre_tokenizer = BertPreTokenizer.new()
+        tokenizer.pre_tokenizer = BertPreTokenizer()
 
         if add_special_tokens and vocab_file is not None:
             sep_token_id = tokenizer.token_to_id(sep_token)

bindings/python/tokenizers/implementations/byte_level_bpe.py

@@ -45,13 +45,12 @@ class ByteLevelBPETokenizer(BaseTokenizer):
             else:
                 tokenizer.normalizer = normalizers[0]
 
-        tokenizer.pre_tokenizer = pre_tokenizers.ByteLevel.new(add_prefix_space=add_prefix_space)
+        tokenizer.pre_tokenizer = pre_tokenizers.ByteLevel(
+            add_prefix_space=add_prefix_space
+        )
         tokenizer.decoder = decoders.ByteLevel()
 
-        parameters = {
-            "model": "ByteLevelBPE",
-            "add_prefix_space": add_prefix_space,
-        }
+        parameters = {"model": "ByteLevelBPE", "add_prefix_space": add_prefix_space}
 
         super().__init__(tokenizer, parameters)
 

bindings/python/tokenizers/implementations/char_level_bpe.py

@@ -51,7 +51,7 @@ class CharBPETokenizer(BaseTokenizer):
             else:
                 tokenizer.normalizer = normalizers[0]
 
-        tokenizer.pre_tokenizer = pre_tokenizers.WhitespaceSplit.new()
+        tokenizer.pre_tokenizer = pre_tokenizers.WhitespaceSplit()
         tokenizer.decoder = decoders.BPEDecoder(suffix=suffix)
 
         parameters = {

bindings/python/tokenizers/implementations/sentencepiece_bpe.py

@@ -28,9 +28,11 @@ class SentencePieceBPETokenizer(BaseTokenizer):
 
         tokenizer.add_special_tokens([ unk_token ])
 
+
         tokenizer.normalizer = NFKC()
-        tokenizer.pre_tokenizer = pre_tokenizers.Metaspace.new(replacement=replacement,
-                                                               add_prefix_space=add_prefix_space)
+        tokenizer.pre_tokenizer = pre_tokenizers.Metaspace(
+            replacement=replacement, add_prefix_space=add_prefix_space
+        )
         tokenizer.decoder = decoders.Metaspace(
             replacement=replacement, add_prefix_space=add_prefix_space
         )

bindings/python/tokenizers/pre_tokenizers/__init__.pyi

@@ -21,7 +21,7 @@ class ByteLevel(PreTokenizer):
     """
 
     @staticmethod
-    def new(add_prefix_space: Optional[bool]=True) -> PreTokenizer:
+    def __init__(self, add_prefix_space: Optional[bool] = True) -> None:
         """ Instantiate a new ByteLevel PreTokenizer
 
         Args:
@@ -50,8 +50,7 @@ class Whitespace(PreTokenizer):
     This pre-tokenizer simply splits using the following regex: `\w+|[^\w\s]+`
     """
 
-    @staticmethod
-    def new() -> PreTokenizer:
+    def __init__(self) -> None:
         """ Instantiate a new Whitespace PreTokenizer """
         pass
 
@@ -61,8 +60,7 @@ class WhitespaceSplit(PreTokenizer):
     This pre-tokenizer simply splits on the whitespace. Works like `.split()`
     """
 
-    @staticmethod
-    def new() -> PreTokenizer:
+    def __init__(self) -> None:
         """ Instantiate a new WhitespaceSplit PreTokenizer """
         pass
 
@@ -73,8 +71,7 @@ class BertPreTokenizer(PreTokenizer):
     Each occurence of a punctuation character will be treated separately.
     """
 
-    @staticmethod
-    def new() -> PreTokenizer:
+    def __init__(self) -> None:
         """ Instantiate a new BertPreTokenizer """
         pass
 
@@ -85,9 +82,7 @@ class Metaspace(PreTokenizer):
     It then tries to split on these spaces.
     """
 
-    @staticmethod
-    def new(replacement: str="▁",
-            add_prefix_space: bool=True) -> PreTokenizer:
+    def __init__(self, replacement: str = "▁", add_prefix_space: bool = True) -> None:
         """ Instantiate a new Metaspace
 
         Args:
@@ -109,11 +104,11 @@ class CharDelimiterSplit(PreTokenizer):
     """
 
     @staticmethod
-    def new(delimiter: str) -> PreTokenizer:
+    def __init__(self, delimiter: str) -> None:
         """ Instantiate a new CharDelimiterSplit PreTokenizer
 
         Args:
             delimiter: str:
                 The delimiter char that will be used to split input
         """
-        pass
+        pass