Simplify Whitespace pre_tokenizer

tokenizers/src/pre_tokenizers/whitespace.rs

@@ -1,68 +1,29 @@
-use std::fmt;
-
 use regex::Regex;
-use serde::{Deserialize, Deserializer, Serialize};
 
 use crate::tokenizer::{
     pattern::Invert, PreTokenizedString, PreTokenizer, Result, SplitDelimiterBehavior,
 };
-use serde::de::{Error, Visitor};
 
-#[derive(Clone, Debug, Serialize)]
-#[serde(tag = "type")]
-pub struct Whitespace {
-    #[serde(default = "default_regex", skip)]
-    re: Regex,
-}
-
-fn default_regex() -> Regex {
-    Regex::new(r"\w+|[^\w\s]+").unwrap()
-}
+#[derive(Clone, Debug)]
+pub struct Whitespace;
+impl_serde_unit_struct!(WhitespaceVisitor, Whitespace);
 
 impl Default for Whitespace {
     fn default() -> Self {
-        Self {
-            re: default_regex(),
-        }
+        Self
     }
 }
 
 impl PreTokenizer for Whitespace {
     fn pre_tokenize(&self, pretokenized: &mut PreTokenizedString) -> Result<()> {
-        pretokenized.split(|_, normalized| {
-            normalized.split(Invert(&self.re), SplitDelimiterBehavior::Removed)
-        })
-    }
-}
-
-// manually implement deserialize because Whitespace is not a unit-struct but is
-// serialized like one.
-impl<'de> Deserialize<'de> for Whitespace {
-    fn deserialize<D>(deserializer: D) -> std::result::Result<Self, D::Error>
-    where
-        D: Deserializer<'de>,
-    {
-        deserializer.deserialize_map(WhitespaceVisitor)
-    }
-}
-struct WhitespaceVisitor;
-impl<'de> Visitor<'de> for WhitespaceVisitor {
-    type Value = Whitespace;
-    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
-        write!(formatter, "Whitespace")
-    }
-
-    fn visit_map<A>(self, mut map: A) -> std::result::Result<Self::Value, A::Error>
-    where
-        A: serde::de::MapAccess<'de>,
-    {
-        let maybe_type = map.next_entry::<String, String>()?;
-        let maybe_type_str = maybe_type.as_ref().map(|(k, v)| (k.as_str(), v.as_str()));
-        match maybe_type_str {
-            Some(("type", "Whitespace")) => Ok(Whitespace::default()),
-            Some((_, ty)) => Err(Error::custom(&format!("Expected Whitespace, got {}", ty))),
-            None => Err(Error::custom("Expected type: Whitespace")),
+        lazy_static! {
+            static ref RE: Regex = Regex::new(r"\w+|[^\w\s]+").unwrap();
         }
+        let re_ref: &Regex = &RE;
+
+        pretokenized.split(|_, normalized| {
+            normalized.split(Invert(re_ref), SplitDelimiterBehavior::Removed)
+        })
     }
 }