2026-1-6

venv/Lib/site-packages/whoosh/lang/snowball/danish.py

@@ -0,0 +1,115 @@
+from .bases import _ScandinavianStemmer
+
+from whoosh.compat import u
+
+
+class DanishStemmer(_ScandinavianStemmer):
+    """
+    The Danish Snowball stemmer.
+
+    :cvar __vowels: The Danish vowels.
+    :type __vowels: unicode
+    :cvar __consonants: The Danish consonants.
+    :type __consonants: unicode
+    :cvar __double_consonants: The Danish double consonants.
+    :type __double_consonants: tuple
+    :cvar __s_ending: Letters that may directly appear before a word final 's'.
+    :type __s_ending: unicode
+    :cvar __step1_suffixes: Suffixes to be deleted in step 1 of the algorithm.
+    :type __step1_suffixes: tuple
+    :cvar __step2_suffixes: Suffixes to be deleted in step 2 of the algorithm.
+    :type __step2_suffixes: tuple
+    :cvar __step3_suffixes: Suffixes to be deleted in step 3 of the algorithm.
+    :type __step3_suffixes: tuple
+    :note: A detailed description of the Danish
+           stemming algorithm can be found under
+           http://snowball.tartarus.org/algorithms/danish/stemmer.html
+
+    """
+
+    # The language's vowels and other important characters are defined.
+    __vowels = u("aeiouy\xE6\xE5\xF8")
+    __consonants = "bcdfghjklmnpqrstvwxz"
+    __double_consonants = ("bb", "cc", "dd", "ff", "gg", "hh", "jj",
+                           "kk", "ll", "mm", "nn", "pp", "qq", "rr",
+                           "ss", "tt", "vv", "ww", "xx", "zz")
+    __s_ending = u("abcdfghjklmnoprtvyz\xE5")
+
+    # The different suffixes, divided into the algorithm's steps
+    # and organized by length, are listed in tuples.
+    __step1_suffixes = ("erendes", "erende", "hedens", "ethed",
+                        "erede", "heden", "heder", "endes",
+                        "ernes", "erens", "erets", "ered",
+                        "ende", "erne", "eren", "erer", "heds",
+                        "enes", "eres", "eret", "hed", "ene", "ere",
+                        "ens", "ers", "ets", "en", "er", "es", "et",
+                        "e", "s")
+    __step2_suffixes = ("gd", "dt", "gt", "kt")
+    __step3_suffixes = ("elig", u("l\xF8st"), "lig", "els", "ig")
+
+    def stem(self, word):
+        """
+        Stem a Danish word and return the stemmed form.
+
+        :param word: The word that is stemmed.
+        :type word: str or unicode
+        :return: The stemmed form.
+        :rtype: unicode
+
+        """
+        # Every word is put into lower case for normalization.
+        word = word.lower()
+
+        # After this, the required regions are generated
+        # by the respective helper method.
+        r1 = self._r1_scandinavian(word, self.__vowels)
+
+        # Then the actual stemming process starts.
+        # Every new step is explicitly indicated
+        # according to the descriptions on the Snowball website.
+
+        # STEP 1
+        for suffix in self.__step1_suffixes:
+            if r1.endswith(suffix):
+                if suffix == "s":
+                    if word[-2] in self.__s_ending:
+                        word = word[:-1]
+                        r1 = r1[:-1]
+                else:
+                    word = word[:-len(suffix)]
+                    r1 = r1[:-len(suffix)]
+                break
+
+        # STEP 2
+        for suffix in self.__step2_suffixes:
+            if r1.endswith(suffix):
+                word = word[:-1]
+                r1 = r1[:-1]
+                break
+
+        # STEP 3
+        if r1.endswith("igst"):
+            word = word[:-2]
+            r1 = r1[:-2]
+
+        for suffix in self.__step3_suffixes:
+            if r1.endswith(suffix):
+                if suffix == u("l\xF8st"):
+                    word = word[:-1]
+                    r1 = r1[:-1]
+                else:
+                    word = word[:-len(suffix)]
+                    r1 = r1[:-len(suffix)]
+
+                    if r1.endswith(self.__step2_suffixes):
+                        word = word[:-1]
+                        r1 = r1[:-1]
+                break
+
+        # STEP 4: Undouble
+        for double_cons in self.__double_consonants:
+            if word.endswith(double_cons) and len(word) > 3:
+                word = word[:-1]
+                break
+
+        return word