Move stemmer classes to sphinx.util.stemmer

sphinx/search/en.py

@@ -10,13 +10,7 @@
 """
 
 from sphinx.search import SearchLanguage
-
-try:
-    from Stemmer import Stemmer as PyStemmer
-    PYSTEMMER = True
-except ImportError:
-    from sphinx.util.stemmer import PorterStemmer
-    PYSTEMMER = False
+from sphinx.util.stemmer import get_stemmer
 
 english_stopwords = set("""
 a  and  are  as  at
@@ -225,25 +219,7 @@ class SearchEnglish(SearchLanguage):
 
     def init(self, options):
         # type: (Dict) -> None
-        if PYSTEMMER:
-            class Stemmer(object):
-                def __init__(self):
-                    # type: () -> None
-                    self.stemmer = PyStemmer('porter')
-
-                def stem(self, word):
-                    # type: (unicode) -> unicode
-                    return self.stemmer.stemWord(word)
-        else:
-            class Stemmer(PorterStemmer):
-                """All those porter stemmer implementations look hideous;
-                make at least the stem method nicer.
-                """
-                def stem(self, word):
-                    # type: (unicode) -> unicode
-                    return PorterStemmer.stem(self, word, 0, len(word) - 1)
-
-        self.stemmer = Stemmer()
+        self.stemmer = get_stemmer()
 
     def stem(self, word):
         # type: (unicode) -> unicode

sphinx/search/zh.py

@@ -13,13 +13,7 @@ import os
 import re
 
 from sphinx.search import SearchLanguage
-
-try:
-    from Stemmer import Stemmer as PyStemmer
-    PYSTEMMER = True
-except ImportError:
-    from sphinx.util.stemmer import PorterStemmer
-    PYSTEMMER = False
+from sphinx.util.stemmer import get_stemmer
 
 try:
     import jieba
@@ -244,25 +238,7 @@ class SearchChinese(SearchLanguage):
             if dict_path and os.path.isfile(dict_path):
                 jieba.set_dictionary(dict_path)
 
-        if PYSTEMMER:
-            class Stemmer(object):
-                def __init__(self):
-                    # type: () -> None
-                    self.stemmer = PyStemmer('porter')
-
-                def stem(self, word):
-                    # type: (unicode) -> unicode
-                    return self.stemmer.stemWord(word)
-        else:
-            class Stemmer(PorterStemmer):
-                """All those porter stemmer implementations look hideous;
-                make at least the stem method nicer.
-                """
-                def stem(self, word):
-                    # type: (unicode) -> unicode
-                    return PorterStemmer.stem(self, word, 0, len(word) - 1)
-
-        self.stemmer = Stemmer()
+        self.stemmer = get_stemmer()
 
     def split(self, input):
         # type: (unicode) -> List[unicode]

sphinx/util/stemmer/__init__.py

@@ -0,0 +1,51 @@
+# -*- coding: utf-8 -*-
+"""
+    sphinx.util.stemmer
+    ~~~~~~~~~~~~~~~~~~~
+
+    Word stemming utilities for Sphinx.
+
+    :copyright: Copyright 2007-2016 by the Sphinx team, see AUTHORS.
+    :license: BSD, see LICENSE for details.
+"""
+
+from sphinx.util.stemmer.porter import PorterStemmer
+
+try:
+    from Stemmer import Stemmer as _PyStemmer
+    PYSTEMMER = True
+except ImportError:
+    PYSTEMMER = False
+
+
+class BaseStemmer(object):
+    def stem(self, word):
+        # type: (unicode) -> unicode
+        raise NotImplemented
+
+
+class PyStemmer(BaseStemmer):
+    def __init__(self):
+        # type: () -> None
+        self.stemmer = _PyStemmer('porter')
+
+    def stem(self, word):
+        # type: (unicode) -> unicode
+        return self.stemmer.stemWord(word)
+
+
+class StandardStemmer(BaseStemmer, PorterStemmer):
+    """All those porter stemmer implementations look hideous;
+    make at least the stem method nicer.
+    """
+    def stem(self, word):
+        # type: (unicode) -> unicode
+        return PorterStemmer.stem(self, word, 0, len(word) - 1)
+
+
+def get_stemmer():
+    # type: () -> BaseStemmer
+    if PYSTEMMER:
+        return PyStemmer()
+    else:
+        return StandardStemmer()

sphinx/util/stemmer/porter.py

@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 """
-    sphinx.util.stemmer
-    ~~~~~~~~~~~~~~~~~~~
+    sphinx.util.stemmer.porter
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~
 
     Porter Stemming Algorithm