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stbi/Lib/site-packages/Sastrawi/Stemmer/Stemmer.py

+import re
+from Sastrawi.Stemmer.Context.Visitor.VisitorProvider import VisitorProvider
+from Sastrawi.Stemmer.Filter import TextNormalizer
+from Sastrawi.Stemmer.Context.Context import Context
+
+class Stemmer(object):
+    """Indonesian Stemmer.
+    Nazief & Adriani, CS Stemmer, ECS Stemmer, Improved ECS.
+
+    @link https://github.com/sastrawi/sastrawi/wiki/Resources
+    """
+    def __init__(self, dictionary):
+        self.dictionary = dictionary
+        self.visitor_provider = VisitorProvider()
+
+    def get_dictionary(self):
+        return self.dictionary
+
+    def stem(self, text):
+        """Stem a text string to its common stem form."""
+        normalizedText = TextNormalizer.normalize_text(text)
+
+        words = normalizedText.split(' ')
+        stems = []
+
+        for word in words:
+            stems.append(self.stem_word(word))
+
+        return ' '.join(stems)
+
+    def stem_word(self, word):
+        """Stem a word to its common stem form."""
+        if self.is_plural(word):
+            return self.stem_plural_word(word)
+        else:
+            return self.stem_singular_word(word)
+
+    def is_plural(self, word):
+        #-ku|-mu|-nya
+        #nikmat-Ku, etc
+        matches = re.match(r'^(.*)-(ku|mu|nya|lah|kah|tah|pun)$', word)
+        if matches:
+            return matches.group(1).find('-') != -1
+
+        return word.find('-') != -1
+
+    def stem_plural_word(self, plural):
+        """Stem a plural word to its common stem form.
+        Asian J. (2007) "Effective Techniques for Indonesian Text Retrieval" page 76-77.
+
+        @link   http://researchbank.rmit.edu.au/eserv/rmit:6312/Asian.pdf
+        """
+        matches = re.match(r'^(.*)-(.*)$', plural)
+        #translated from PHP conditional check:
+        #if (!isset($words[1]) || !isset($words[2]))
+        if not matches:
+            return plural
+        words = [matches.group(1), matches.group(2)]
+
+        #malaikat-malaikat-nya -> malaikat malaikat-nya
+        suffix = words[1]
+        suffixes = ['ku', 'mu', 'nya', 'lah', 'kah', 'tah', 'pun']
+        matches = re.match(r'^(.*)-(.*)$', words[0])
+        if suffix in suffixes and matches:
+            words[0] = matches.group(1)
+            words[1] = matches.group(2) + '-' + suffix
+
+        #berbalas-balasan -> balas
+        rootWord1 = self.stem_singular_word(words[0])
+        rootWord2 = self.stem_singular_word(words[1])
+
+        #meniru-nirukan -> tiru
+        if not self.dictionary.contains(words[1]) and rootWord2 == words[1]:
+            rootWord2 = self.stem_singular_word('me' + words[1])
+
+        if rootWord1 == rootWord2:
+            return rootWord1
+        else:
+            return plural
+
+    def stem_singular_word(self, word):
+        """Stem a singular word to its common stem form."""
+        context = Context(word, self.dictionary, self.visitor_provider)
+        context.execute()
+
+        return context.result
+