Added ability to inspect a 'Sequence' decoder and the `AddedVocabular…

…y`. (#1443)

* Fixes.

* Fixes.

tokenizers/src/decoders/sequence.rs

@@ -13,6 +13,14 @@ impl Sequence {
     pub fn new(decoders: Vec<DecoderWrapper>) -> Self {
         Self { decoders }
     }
+
+    pub fn get_decoders(&self) -> &[DecoderWrapper] {
+        &self.decoders
+    }
+
+    pub fn get_decoders_mut(&mut self) -> &mut [DecoderWrapper] {
+        &mut self.decoders
+    }
 }
 
 impl Decoder for Sequence {

tokenizers/src/tokenizer/added_vocabulary.rs

@@ -139,7 +139,7 @@ fn space_rightmost_at_start(sentence: &str) -> usize {
 /// exist as required.
 ///
 #[derive(Clone, Debug)]
-pub(super) struct AddedVocabulary {
+pub struct AddedVocabulary {
     /// Contains the mapping from String (token content) to ID. This map contains both special
     /// tokens and classic added tokens that were added to the this vocabulary.
     added_tokens_map: HashMap<String, u32>,
@@ -192,6 +192,11 @@ impl AddedVocabulary {
         self.added_tokens_map.len()
     }
 
+    /// Whether or not this vocabulary is empty
+    pub fn is_empty(&self) -> bool {
+        self.added_tokens_map.is_empty()
+    }
+
     /// Get the additional vocabulary
     pub fn get_vocab(&self) -> &HashMap<String, u32> {
         &self.added_tokens_map
@@ -487,6 +492,12 @@ impl AddedVocabulary {
     }
 }
 
+impl Default for AddedVocabulary {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 #[derive(Debug, Serialize, Deserialize)]
 pub(super) struct AddedTokenWithId {
     /// The id assigned to this token

tokenizers/src/tokenizer/mod.rs

@@ -384,6 +384,12 @@ where
         self
     }
 
+    /// Set the added vocabulary.
+    pub fn with_added_vocabulary(mut self, added_vocabulary: AddedVocabulary) -> Self {
+        self.added_vocabulary = added_vocabulary;
+        self
+    }
+
     /// Set the trunaction parameters.
     #[must_use]
     pub fn with_truncation(mut self, trunc: Option<TruncationParams>) -> Self {
@@ -598,6 +604,17 @@ where
         &self.model
     }
 
+    /// Set the added vocabulary.
+    pub fn with_added_vocabulary(&mut self, added_vocabulary: AddedVocabulary) -> &mut Self {
+        self.added_vocabulary = added_vocabulary;
+        self
+    }
+
+    /// Get the added vocabulary
+    pub fn get_added_vocabulary(&self) -> &AddedVocabulary {
+        &self.added_vocabulary
+    }
+
     /// Set the truncation parameters
     ///
     /// Fails if `stride` is too high relative to `max_length` and `post_processor.added_tokens()`