9e9f172f81
previous impl always did full utf8 decode of rune if we assume most tokens are not possessive this is unnecessary and even if they are, we only need to chop off last to runes so, now we only decode last rune of token, and if it looks like s/S then we proceed to decode second to last rune, and then only if it looks like any form of apostrophe, do we make any changes to token, again by just reslicing original to chop off the possessive extension
63 lines
2.2 KiB
Go
63 lines
2.2 KiB
Go
// Copyright (c) 2014 Couchbase, Inc.
|
||
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
|
||
// except in compliance with the License. You may obtain a copy of the License at
|
||
// http://www.apache.org/licenses/LICENSE-2.0
|
||
// Unless required by applicable law or agreed to in writing, software distributed under the
|
||
// License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
|
||
// either express or implied. See the License for the specific language governing permissions
|
||
// and limitations under the License.
|
||
|
||
package en
|
||
|
||
import (
|
||
"unicode/utf8"
|
||
|
||
"github.com/blevesearch/bleve/analysis"
|
||
"github.com/blevesearch/bleve/registry"
|
||
)
|
||
|
||
// PossessiveName is the name PossessiveFilter is registered as
|
||
// in the bleve registry.
|
||
const PossessiveName = "possessive_en"
|
||
|
||
const rightSingleQuotationMark = '’'
|
||
const apostrophe = '\''
|
||
const fullWidthApostrophe = '＇'
|
||
|
||
const apostropheChars = rightSingleQuotationMark + apostrophe + fullWidthApostrophe
|
||
|
||
// PossessiveFilter implements a TokenFilter which
|
||
// strips the English possessive suffix ('s) from tokens.
|
||
// It handle a variety of apostrophe types, is case-insensitive
|
||
// and doesn't distinguish between possessive and contraction.
|
||
// (ie "She's So Rad" becomes "She So Rad")
|
||
type PossessiveFilter struct {
|
||
}
|
||
|
||
func NewPossessiveFilter() *PossessiveFilter {
|
||
return &PossessiveFilter{}
|
||
}
|
||
|
||
func (s *PossessiveFilter) Filter(input analysis.TokenStream) analysis.TokenStream {
|
||
for _, token := range input {
|
||
lastRune, lastRuneSize := utf8.DecodeLastRune(token.Term)
|
||
if lastRune == 's' || lastRune == 'S' {
|
||
nextLastRune, nextLastRuneSize := utf8.DecodeLastRune(token.Term[:len(token.Term)-lastRuneSize])
|
||
if nextLastRune == rightSingleQuotationMark ||
|
||
nextLastRune == apostrophe ||
|
||
nextLastRune == fullWidthApostrophe {
|
||
token.Term = token.Term[:len(token.Term)-lastRuneSize-nextLastRuneSize]
|
||
}
|
||
}
|
||
}
|
||
return input
|
||
}
|
||
|
||
func PossessiveFilterConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.TokenFilter, error) {
|
||
return NewPossessiveFilter(), nil
|
||
}
|
||
|
||
func init() {
|
||
registry.RegisterTokenFilter(PossessiveName, PossessiveFilterConstructor)
|
||
}
|