A TokenFilter that applies GreekStemmer to stem Greek words.
To prevent terms from being stemmed use an instance of SetKeywordMarkerFilter or a custom TokenFilter that sets the KeywordAttribute before this TokenStream.
NOTE: Input is expected to be casefolded for Greek (including folding of final sigma to sigma), and with diacritics removed. This can be achieved by using either GreekLowerCaseFilter or ICUFoldingFilter before GreekStemFilter. @lucene.experimental