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|
package StemmerRu
import (
"runtime"
"strings"
)
var (
perfectiveGerund = [][]string{{`в`, `вши`, `вшись`}, {`ив`, `ивши`, `ившись`, `ыв`, `ывши`, `ывшись`}}
adjective = []string{`ее`, `ие`, `ые`, `ое`, `ими`, `ыми`, `ей`, `ий`, `ый`, `ой`, `ем`, `им`, `ым`, `ом`, `его`, `ого`, `ему`, `ому`, `их`, `ых`, `ую`, `юю`, `ая`, `яя`, `ою`, `ею`}
participle = [][]string{{`ем`, `нн`, `вш`, `ющ`, `щ`}, {`ивш`, `ывш`, `ующ`}}
reflexive = []string{`ся`, `сь`}
verb = [][]string{{`ла`, `на`, `ете`, `йте`, `ли`, `й`, `л`, `ем`, `н`, `ло`, `но`, `ет`, `ют`, `ны`, `ть`, `ешь`, `нно`}, {`ила`, `ыла`, `ена`, `ейте`, `уйте`, `ите`, `или`, `ыли`, `ей`, `уй`, `ил`, `ыл`, `им`, `ым`, `ен`, `ило`, `ыло`, `ено`, `ят`, `ует`, `уют`, `ит`, `ыт`, `ены`, `ить`, `ыть`, `ишь`, `ую`, `ю`}}
noun = []string{`а`, `ев`, `ов`, `ие`, `ье`, `е`, `иями`, `ями`, `ами`, `еи`, `ии`, `и`, `ией`, `ей`, `ой`, `ий`, `й`, `иям`, `ям`, `ием`, `ем`, `ам`, `ом`, `о`, `у`, `ах`, `иях`, `ях`, `ы`, `ь`, `ию`, `ью`, `ю`, `ия`, `ья`, `я`}
superlative = []string{`ейш`, `ейше`}
derivational = []string{`ост`, `ость`}
vowels = `аеиоуыэюя`
)
func Stem(word string) string {
word = strings.Replace(word, `ё`, `е`, -1)
RVpos := getRVPart(word)
if RVpos == -1 {
return word
}
R1pos := getRNPart(word, 0)
R2pos := getRNPart(word, R1pos)
if R2pos < RVpos {
R2pos = 0
} else {
R2pos -= RVpos
}
suffix := string([]rune(word)[RVpos:])
prefix := string([]rune(word)[:RVpos])
// Step 1
suffix, isTrimmed := trimSuffix(suffix, perfectiveGerund[1], perfectiveGerund[0])
if !isTrimmed {
suffix, isTrimmed = trimSuffix(suffix, reflexive, nil)
suffix, isTrimmed = trimAdjectival(suffix)
if !isTrimmed {
suffix, isTrimmed = trimSuffix(suffix, verb[1], verb[0])
if !isTrimmed {
suffix, _ = trimSuffix(suffix, noun, nil)
}
}
}
// Step 2
suffix = strings.TrimSuffix(suffix, `и`)
// Step 3
if R2pos < len([]rune(suffix)) {
R2suffix := string([]rune(suffix)[R2pos:])
R2prefix := string([]rune(suffix)[:R2pos])
R2suffix, _ = trimSuffix(R2suffix, derivational, nil)
suffix = R2prefix + R2suffix
}
// Step 4
suffix, isTrimmed = trimNN(suffix)
if !isTrimmed {
suffix, isTrimmed = trimSuffix(suffix, superlative, nil)
if isTrimmed {
suffix, _ = trimNN(suffix)
} else {
suffix = strings.TrimSuffix(suffix, `ь`)
}
}
return prefix + suffix
}
func trimNN(word string) (string, bool) {
if strings.HasSuffix(word, `нн`) {
return strings.TrimSuffix(word, `нн`) + `н`, true
}
return word, false
}
func trimAdjectival(word string) (string, bool) {
isTrimmedParticiple := false
word, isTrimmedAdjective := trimSuffix(word, adjective, nil)
if isTrimmedAdjective {
word, isTrimmedParticiple = trimSuffix(word, participle[1], participle[0])
}
return word, isTrimmedAdjective || isTrimmedParticiple
}
func trimSuffix(word string, suffixes []string, suffixes2 []string) (string, bool) {
for _, suffix := range suffixes {
if strings.HasSuffix(word, suffix) {
return strings.TrimSuffix(word, suffix), true
}
}
if suffixes2 != nil {
for _, suffix := range suffixes2 {
if strings.HasSuffix(word, `а`+suffix) ||
strings.HasSuffix(word, `я`+suffix) {
return strings.TrimSuffix(word, suffix), true
}
}
}
return word, false
}
func isVowel(char rune) bool {
return strings.Contains(vowels, string(char))
}
func getRVPart(word string) int {
chars := []rune(word)
for idx, char := range chars {
if isVowel(char) {
return idx + 1
}
}
return -1
}
func getRNPart(word string, startPos int) int {
chars := []rune(word)[startPos:]
for idx, char := range chars {
if idx+2 < len(chars) {
if isVowel(char) && !isVowel(chars[idx+1]) {
return startPos + idx + 2
}
}
}
return startPos
}
// Code from https://github.com/caneroj1/stemmer
// StemMultiple accepts a slice of strings and stems each of them.
func StemMultiple(words []string) (output []string) {
output = make([]string, len(words))
for idx, word := range words {
output[idx] = Stem(word)
}
return
}
// StemMultipleMutate accepts a pointer to a slice of strings and stems them in place.
// It modifies the original slice.
func StemMultipleMutate(words *[]string) {
for idx, word := range *words {
(*words)[idx] = Stem(word)
}
}
// StemConcurrent accepts a pointer to a slice of strings and stems them in place.
// It tries to offload the work into multiple threads. It makes no guarantees about
// the order of the stems in the modified slice.
func StemConcurrent(words *[]string) {
CPUs := runtime.NumCPU()
length := len(*words)
output := make(chan string)
partition := length / CPUs
var CPU int
for CPU = 0; CPU < CPUs; CPU++ {
go func(strs []string) {
for _, word := range strs {
output <- Stem(word)
}
}((*words)[CPU*partition : (CPU+1)*partition])
}
// if there are leftover words, stem them now
if length-(CPU)*partition > 0 {
go func(strs []string) {
for _, word := range strs {
output <- Stem(word)
}
}((*words)[(CPU)*partition : length])
}
for idx := 0; idx < length; idx++ {
(*words)[idx] = <-output
}
}
|
