1 files changed, 76 insertions, 0 deletions
diff --git a/vendor/elasticlunr-rs/src/lang/ja.rs b/vendor/elasticlunr-rs/src/lang/ja.rs
new file mode 100644
index 000000000..e38fcde9f
--- /dev/null
+++ b/vendor/elasticlunr-rs/src/lang/ja.rs
@@ -0,0 +1,76 @@
+use super::{common::RegexTrimmer, Language};
+use crate::pipeline::{FnWrapper, Pipeline};
+use lindera::tokenizer::{Tokenizer, TokenizerConfig};
+use lindera_core::viterbi::Mode;
+
+#[derive(Clone)]
+pub struct Japanese {
+    tokenizer: Tokenizer,
+}
+
+impl Japanese {
+    pub fn new() -> Self {
+        let config = TokenizerConfig {
+            mode: Mode::Decompose(Default::default()),
+            ..Default::default()
+        };
+        Self::with_config(config)
+    }
+
+    pub fn with_config(config: TokenizerConfig) -> Self {
+        // NB: unwrap() is okay since the errors are only related to user-supplied dictionaries.
+        let tokenizer = Tokenizer::with_config(config).unwrap();
+        Self { tokenizer }
+    }
+}
+
+impl Language for Japanese {
+    fn name(&self) -> String {
+        "Japanese".into()
+    }
+    fn code(&self) -> String {
+        "ja".into()
+    }
+
+    fn tokenize(&self, text: &str) -> Vec<String> {
+        self.tokenizer
+            .tokenize(text)
+            .unwrap()
+            .into_iter()
+            .filter_map(|tok| match tok.detail.get(0).map(|d| d.as_str()) {
+                Some("助詞") | Some("助動詞") | Some("記号") | Some("UNK") => None,
+                _ => Some(tok.text.to_string()),
+            })
+            .collect()
+    }
+
+    fn make_pipeline(&self) -> Pipeline {
+        Pipeline {
+            queue: vec![
+                Box::new(RegexTrimmer::new("trimmer-ja", WORD_CHARS)),
+                Box::new(FnWrapper("stemmer-ja".into(), stemmer)),
+            ],
+        }
+    }
+}
+
+const WORD_CHARS: &str = r"0-9A-Za-z\p{Hiragana}\p{Katakana}\p{Unified_Ideograph}";
+
+fn stemmer(token: String) -> Option<String> {
+    Some(token)
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::pipeline::PipelineFn;
+    use super::*;
+
+    #[test]
+    fn test_trimmer() {
+        let trimmer = RegexTrimmer::new("trimmer-ja".into(), WORD_CHARS);
+        assert_eq!(
+            trimmer.filter("  こんにちは、世界！".to_string()),
+            Some("こんにちは、世界".to_string())
+        );
+    }
+}