Revert "Fix non english stemmers (#521)"

This reverts commit 2cd31bcda2.

src/tokenizer/mod.rs

@@ -228,27 +228,27 @@ pub mod tests {
     fn test_non_en_tokenizer() {
         let tokenizer_manager = TokenizerManager::default();
         tokenizer_manager.register(
-            "el_stem",
+            "es_stem",
             SimpleTokenizer
                 .filter(RemoveLongFilter::limit(40))
                 .filter(LowerCaser)
-                .filter(Stemmer::new(Language::Greek)),
+                .filter(Stemmer::new(Language::Spanish)),
         );
-        let en_tokenizer = tokenizer_manager.get("el_stem").unwrap();
+        let en_tokenizer = tokenizer_manager.get("es_stem").unwrap();
         let mut tokens: Vec<Token> = vec![];
         {
             let mut add_token = |token: &Token| {
                 tokens.push(token.clone());
             };
             en_tokenizer
-                .token_stream("Καλημέρα, χαρούμενε φορολογούμενε!")
+                .token_stream("Hola, feliz contribuyente!")
                 .process(&mut add_token);
         }
 
         assert_eq!(tokens.len(), 3);
-        assert_token(&tokens[0], 0, "καλημερ", 0, 16);
+        assert_token(&tokens[0], 0, "hola", 0, 4);
-        assert_token(&tokens[1], 1, "χαρουμεν", 18, 36);
+        assert_token(&tokens[1], 1, "feliz", 6, 11);
-        assert_token(&tokens[2], 2, "φορολογουμεν", 37, 63);
+        assert_token(&tokens[2], 2, "contribuyent", 12, 25);
     }
 
     #[test]

src/tokenizer/stemmer.rs

@@ -2,6 +2,7 @@
 
 use super::{Token, TokenFilter, TokenStream};
 use rust_stemmers::{self, Algorithm};
+use std::sync::Arc;
 
 /// Available stemmer languages.
 #[derive(Debug, Serialize, Deserialize, Eq, PartialEq, Copy, Clone)]
@@ -56,14 +57,14 @@ impl Language {
 /// Tokens are expected to be lowercased beforehand.
 #[derive(Clone)]
 pub struct Stemmer {
-    stemmer_algorithm: Algorithm,
+    stemmer_algorithm: Arc<Algorithm>,
 }
 
 impl Stemmer {
     /// Creates a new Stemmer `TokenFilter` for a given language algorithm.
     pub fn new(language: Language) -> Stemmer {
         Stemmer {
-            stemmer_algorithm: language.algorithm(),
+            stemmer_algorithm: Arc::new(language.algorithm()),
         }
     }
 }
@@ -82,7 +83,7 @@ where
     type ResultTokenStream = StemmerTokenStream<TailTokenStream>;
 
     fn transform(&self, token_stream: TailTokenStream) -> Self::ResultTokenStream {
-        let inner_stemmer = rust_stemmers::Stemmer::create(self.stemmer_algorithm);
+        let inner_stemmer = rust_stemmers::Stemmer::create(Algorithm::English);
         StemmerTokenStream::wrap(inner_stemmer, token_stream)
     }
 }