from .bases import _StandardStemmer from whoosh.compat import u class ItalianStemmer(_StandardStemmer): """ The Italian Snowball stemmer. :cvar __vowels: The Italian vowels. :type __vowels: unicode :cvar __step0_suffixes: Suffixes to be deleted in step 0 of the algorithm. :type __step0_suffixes: tuple :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 :note: A detailed description of the Italian stemming algorithm can be found under http://snowball.tartarus.org/algorithms/italian/stemmer.html """ __vowels = u("aeiou\xE0\xE8\xEC\xF2\xF9") __step0_suffixes = ('gliela', 'gliele', 'glieli', 'glielo', 'gliene', 'sene', 'mela', 'mele', 'meli', 'melo', 'mene', 'tela', 'tele', 'teli', 'telo', 'tene', 'cela', 'cele', 'celi', 'celo', 'cene', 'vela', 'vele', 'veli', 'velo', 'vene', 'gli', 'ci', 'la', 'le', 'li', 'lo', 'mi', 'ne', 'si', 'ti', 'vi') __step1_suffixes = ('atrice', 'atrici', 'azione', 'azioni', 'uzione', 'uzioni', 'usione', 'usioni', 'amento', 'amenti', 'imento', 'imenti', 'amente', 'abile', 'abili', 'ibile', 'ibili', 'mente', 'atore', 'atori', 'logia', 'logie', 'anza', 'anze', 'iche', 'ichi', 'ismo', 'ismi', 'ista', 'iste', 'isti', u('ist\xE0'), u('ist\xE8'), u('ist\xEC'), 'ante', 'anti', 'enza', 'enze', 'ico', 'ici', 'ica', 'ice', 'oso', 'osi', 'osa', 'ose', u('it\xE0'), 'ivo', 'ivi', 'iva', 'ive') __step2_suffixes = ('erebbero', 'irebbero', 'assero', 'assimo', 'eranno', 'erebbe', 'eremmo', 'ereste', 'eresti', 'essero', 'iranno', 'irebbe', 'iremmo', 'ireste', 'iresti', 'iscano', 'iscono', 'issero', 'arono', 'avamo', 'avano', 'avate', 'eremo', 'erete', 'erono', 'evamo', 'evano', 'evate', 'iremo', 'irete', 'irono', 'ivamo', 'ivano', 'ivate', 'ammo', 'ando', 'asse', 'assi', 'emmo', 'enda', 'ende', 'endi', 'endo', 'erai', 'erei', 'Yamo', 'iamo', 'immo', 'irai', 'irei', 'isca', 'isce', 'isci', 'isco', 'ano', 'are', 'ata', 'ate', 'ati', 'ato', 'ava', 'avi', 'avo', u('er\xE0'), 'ere', u('er\xF2'), 'ete', 'eva', 'evi', 'evo', u('ir\xE0'), 'ire', u('ir\xF2'), 'ita', 'ite', 'iti', 'ito', 'iva', 'ivi', 'ivo', 'ono', 'uta', 'ute', 'uti', 'uto', 'ar', 'ir') def stem(self, word): """ Stem an Italian word and return the stemmed form. :param word: The word that is stemmed. :type word: str or unicode :return: The stemmed form. :rtype: unicode """ word = word.lower() step1_success = False # All acute accents are replaced by grave accents. word = (word.replace(u("\xE1"), u("\xE0")) .replace(u("\xE9"), u("\xE8")) .replace(u("\xED"), u("\xEC")) .replace(u("\xF3"), u("\xF2")) .replace(u("\xFA"), u("\xF9"))) # Every occurrence of 'u' after 'q' # is put into upper case. for i in range(1, len(word)): if word[i - 1] == "q" and word[i] == "u": word = "".join((word[:i], "U", word[i + 1:])) # Every occurrence of 'u' and 'i' # between vowels is put into upper case. for i in range(1, len(word) - 1): if word[i - 1] in self.__vowels and word[i + 1] in self.__vowels: if word[i] == "u": word = "".join((word[:i], "U", word[i + 1:])) elif word[i] == "i": word = "".join((word[:i], "I", word[i + 1:])) r1, r2 = self._r1r2_standard(word, self.__vowels) rv = self._rv_standard(word, self.__vowels) # STEP 0: Attached pronoun for suffix in self.__step0_suffixes: if rv.endswith(suffix): if rv[-len(suffix) - 4:-len(suffix)] in ("ando", "endo"): word = word[:-len(suffix)] r1 = r1[:-len(suffix)] r2 = r2[:-len(suffix)] rv = rv[:-len(suffix)] elif (rv[-len(suffix) - 2:-len(suffix)] in ("ar", "er", "ir")): word = "".join((word[:-len(suffix)], "e")) r1 = "".join((r1[:-len(suffix)], "e")) r2 = "".join((r2[:-len(suffix)], "e")) rv = "".join((rv[:-len(suffix)], "e")) break # STEP 1: Standard suffix removal for suffix in self.__step1_suffixes: if word.endswith(suffix): if suffix == "amente" and r1.endswith(suffix): step1_success = True word = word[:-6] r2 = r2[:-6] rv = rv[:-6] if r2.endswith("iv"): word = word[:-2] r2 = r2[:-2] rv = rv[:-2] if r2.endswith("at"): word = word[:-2] rv = rv[:-2] elif r2.endswith(("os", "ic")): word = word[:-2] rv = rv[:-2] elif r2 .endswith("abil"): word = word[:-4] rv = rv[:-4] elif (suffix in ("amento", "amenti", "imento", "imenti") and rv.endswith(suffix)): step1_success = True word = word[:-6] rv = rv[:-6] elif r2.endswith(suffix): step1_success = True if suffix in ("azione", "azioni", "atore", "atori"): word = word[:-len(suffix)] r2 = r2[:-len(suffix)] rv = rv[:-len(suffix)] if r2.endswith("ic"): word = word[:-2] rv = rv[:-2] elif suffix in ("logia", "logie"): word = word[:-2] rv = word[:-2] elif suffix in ("uzione", "uzioni", "usione", "usioni"): word = word[:-5] rv = rv[:-5] elif suffix in ("enza", "enze"): word = "".join((word[:-2], "te")) rv = "".join((rv[:-2], "te")) elif suffix == u("it\xE0"): word = word[:-3] r2 = r2[:-3] rv = rv[:-3] if r2.endswith(("ic", "iv")): word = word[:-2] rv = rv[:-2] elif r2.endswith("abil"): word = word[:-4] rv = rv[:-4] elif suffix in ("ivo", "ivi", "iva", "ive"): word = word[:-3] r2 = r2[:-3] rv = rv[:-3] if r2.endswith("at"): word = word[:-2] r2 = r2[:-2] rv = rv[:-2] if r2.endswith("ic"): word = word[:-2] rv = rv[:-2] else: word = word[:-len(suffix)] rv = rv[:-len(suffix)] break # STEP 2: Verb suffixes if not step1_success: for suffix in self.__step2_suffixes: if rv.endswith(suffix): word = word[:-len(suffix)] rv = rv[:-len(suffix)] break # STEP 3a if rv.endswith(("a", "e", "i", "o", u("\xE0"), u("\xE8"), u("\xEC"), u("\xF2"))): word = word[:-1] rv = rv[:-1] if rv.endswith("i"): word = word[:-1] rv = rv[:-1] # STEP 3b if rv.endswith(("ch", "gh")): word = word[:-1] word = word.replace("I", "i").replace("U", "u") return word