make detect_language return Option<Lang>

src/bin/assess.rs

@@ -25,7 +25,7 @@ fn main() -> io::Result<()> {
         if !label_codes.contains(&id_label_sentence[1]) {
             continue;
         }
-        let detected: Lang = whichlang::detect_language(id_label_sentence[2]);
+        let detected: Lang = whichlang::detect_language(id_label_sentence[2]).unwrap_or(Lang::Eng);
         total += 1;
         if detected.three_letter_code() != id_label_sentence[1] {
             error += 1;

src/lib.rs

@@ -1,3 +1,4 @@
+use std::cmp::Ordering;
 pub use crate::weights::{Lang, LANGUAGES};
 
 #[allow(clippy::all)]
@@ -45,7 +46,7 @@ impl Feature {
     }
 }
 
-pub fn detect_language(text: &str) -> Lang {
+pub fn detect_language(text: &str) -> Option<Lang> {
     let mut scores: [f32; NUM_LANGUAGES] = Default::default();
     let mut num_features: u32 = 0;
     emit_tokens(
@@ -62,8 +63,7 @@ pub fn detect_language(text: &str) -> Lang {
         },
     );
     if num_features == 0 {
-        // By default, we return English
-        return Lang::Eng;
+        return None;
     }
 
     let sqrt_inv_num_features = 1.0f32 / (num_features as f32).sqrt();
@@ -73,13 +73,13 @@ pub fn detect_language(text: &str) -> Lang {
         scores[i] = scores[i] * sqrt_inv_num_features + weights::INTERCEPTS[i];
     }
 
-    let lang_id = scores
+    scores
         .iter()
         .enumerate()
-        .max_by(|(_, &score_left), (_, &score_right)| score_left.partial_cmp(&score_right).unwrap())
+        .max_by(|(_, &score_left), (_, &score_right)| score_left.partial_cmp(&score_right).unwrap_or(Ordering::Equal))
         .map(|(pos, _val)| pos)
-        .unwrap();
-    weights::LANGUAGES[lang_id]
+        .map(|lang_id |  weights::LANGUAGES[lang_id])
+
 }
 
 #[doc(hidden)]
@@ -241,33 +241,33 @@ mod tests {
 
     #[test]
     fn test_empty_str() {
-        assert_eq!(detect_language(""), Lang::Eng);
+        assert_eq!(detect_language(""), None);
     }
 
     #[test]
     fn test_detect_language() {
         // English
-        assert_eq!(detect_language("Hello, happy tax payer"), Lang::Eng);
+        assert_eq!(detect_language("Hello, happy tax payer").unwrap(), Lang::Eng);
         // French
-        assert_eq!(detect_language("Bonjour joyeux contribuable"), Lang::Fra);
+        assert_eq!(detect_language("Bonjour joyeux contribuable").unwrap(), Lang::Fra);
         // German
-        assert_eq!(detect_language("Hallo glücklicher Steuerzahler"), Lang::Deu);
+        assert_eq!(detect_language("Hallo glücklicher Steuerzahler").unwrap(), Lang::Deu);
         // Japanese
-        assert_eq!(detect_language("こんにちは幸せな税金納め"), Lang::Jpn);
+        assert_eq!(detect_language("こんにちは幸せな税金納め").unwrap(), Lang::Jpn);
         // Mandarin chinese
-        assert_eq!(detect_language("你好幸福的纳税人"), Lang::Cmn);
+        assert_eq!(detect_language("你好幸福的纳税人").unwrap(), Lang::Cmn);
         // Turkish
-        assert_eq!(detect_language("Merhaba, mutlu vergi mükellefi"), Lang::Tur);
+        assert_eq!(detect_language("Merhaba, mutlu vergi mükellefi").unwrap(), Lang::Tur);
         // Dutch
-        assert_eq!(detect_language("Hallo, blije belastingbetaler"), Lang::Nld);
+        assert_eq!(detect_language("Hallo, blije belastingbetaler").unwrap(), Lang::Nld);
         // Korean
-        assert_eq!(detect_language("안녕하세요 행복한 납세자입니다"), Lang::Kor);
+        assert_eq!(detect_language("안녕하세요 행복한 납세자입니다").unwrap(), Lang::Kor);
         // Italian
-        assert_eq!(detect_language("Ciao, felice contribuente!"), Lang::Ita);
+        assert_eq!(detect_language("Ciao, felice contribuente!").unwrap(), Lang::Ita);
         // Spanish
-        assert_eq!(detect_language("Hola feliz contribuyente"), Lang::Spa);
-        assert_eq!(detect_language("¡Hola!"), Lang::Spa);
+        assert_eq!(detect_language("Hola feliz contribuyente").unwrap(), Lang::Spa);
+        assert_eq!(detect_language("¡Hola!").unwrap(), Lang::Spa);
         // Portuguese
-        assert_eq!(detect_language("Olá feliz contribuinte"), Lang::Por);
+        assert_eq!(detect_language("Olá feliz contribuinte").unwrap(), Lang::Por);
     }
 }