// Step 4 is the undoubling of double non-vowel endings
// and removal of superlative endings.
//
func step4(word *snowballword.SnowballWord) bool {
// (1) Undouble "н", or, 2) if the word ends with a SUPERLATIVE ending,
// (remove it and undouble н n), or 3) if the word ends ь (') (soft sign)
// remove it.
// Undouble "н"
if word.HasSuffixRunes([]rune("нн")) {
word.RemoveLastNRunes(1)
return true
}
// Remove superlative endings
suffix, _ := word.RemoveFirstSuffix("ейше", "ейш")
if suffix != "" {
// Undouble "н"
if word.HasSuffixRunes([]rune("нн")) {
word.RemoveLastNRunes(1)
}
return true
}
// Remove soft sign
if rsLen := len(word.RS); rsLen > 0 && word.RS[rsLen-1] == 'ь' {
word.RemoveLastNRunes(1)
return true
}
return false
}