# Copyright 2014-2020 by Christopher C. Little.
# This file is part of Abydos.
#
# Abydos is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Abydos is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Abydos. If not, see <http://www.gnu.org/licenses/>.
"""abydos.stemmer._clef_german_plus.
CLEF German plus stemmer
"""
from unicodedata import normalize
from deprecation import deprecated
from ._stemmer import _Stemmer
from .. import __version__
__all__ = ['CLEFGermanPlus', 'clef_german_plus']
[docs]class CLEFGermanPlus(_Stemmer):
"""CLEF German stemmer plus.
The CLEF German stemmer plus is defined at :cite:`Savoy:2005`.
.. versionadded:: 0.3.6
"""
_st_ending = {'b', 'd', 'f', 'g', 'h', 'k', 'l', 'm', 'n', 't'}
_accents = dict(
zip((ord(_) for _ in 'äàáâöòóôïìíîüùúû'), 'aaaaooooiiiiuuuu')
)
[docs] def stem(self, word):
"""Return 'CLEF German stemmer plus' stem.
Parameters
----------
word : str
The word to stem
Returns
-------
str
Word stem
Examples
--------
>>> stmr = CLEFGermanPlus()
>>> clef_german_plus('lesen')
'les'
>>> clef_german_plus('graues')
'grau'
>>> clef_german_plus('buchstabieren')
'buchstabi'
.. versionadded:: 0.1.0
.. versionchanged:: 0.3.6
Encapsulated in class
"""
# lowercase, normalize, and compose
word = normalize('NFC', word.lower())
# remove umlauts
word = word.translate(self._accents)
# Step 1
wlen = len(word) - 1
if wlen > 4 and word[-3:] == 'ern':
word = word[:-3]
elif wlen > 3 and word[-2:] in {'em', 'en', 'er', 'es'}:
word = word[:-2]
elif wlen > 2 and (
word[-1] == 'e'
or (word[-1] == 's' and word[-2] in self._st_ending)
):
word = word[:-1]
# Step 2
wlen = len(word) - 1
if wlen > 4 and word[-3:] == 'est':
word = word[:-3]
elif wlen > 3 and (
word[-2:] in {'er', 'en'}
or (word[-2:] == 'st' and word[-3] in self._st_ending)
):
word = word[:-2]
return word
[docs]@deprecated(
deprecated_in='0.4.0',
removed_in='0.6.0',
current_version=__version__,
details='Use the CLEFGermanPlus.stem method instead.',
)
def clef_german_plus(word):
"""Return 'CLEF German stemmer plus' stem.
This is a wrapper for :py:meth:`CLEFGermanPlus.stem`.
Parameters
----------
word : str
The word to stem
Returns
-------
str
Word stem
Examples
--------
>>> stmr = CLEFGermanPlus()
>>> clef_german_plus('lesen')
'les'
>>> clef_german_plus('graues')
'grau'
>>> clef_german_plus('buchstabieren')
'buchstabi'
.. versionadded:: 0.1.0
"""
return CLEFGermanPlus().stem(word)
if __name__ == '__main__':
import doctest
doctest.testmod()