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bleve/analysis/tokenizers/regexp_tokenizer/regexp_tokenizer.go
Marty Schoch 6b4c86b35a changed whitespace tokenizer to work better on cjk input
now it will return each cjk character as a separate token
this will pair well with a cjk bigram filter for indexing
2014-09-07 14:11:01 -04:00

78 lines
2.1 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 regexp_tokenizer
import (
"fmt"
"regexp"
"strconv"
"github.com/blevesearch/bleve/analysis"
"github.com/blevesearch/bleve/registry"
)
const Name = "regexp"
var IdeographRegexp = regexp.MustCompile(`\p{Han}|\p{Hangul}|\p{Hiragana}|\p{Katakana}`)
type RegexpTokenizer struct {
r *regexp.Regexp
}
func NewRegexpTokenizer(r *regexp.Regexp) *RegexpTokenizer {
return &RegexpTokenizer{
r: r,
}
}
func (rt *RegexpTokenizer) Tokenize(input []byte) analysis.TokenStream {
matches := rt.r.FindAllIndex(input, -1)
rv := make(analysis.TokenStream, len(matches))
for i, match := range matches {
matchBytes := input[match[0]:match[1]]
token := analysis.Token{
Term: matchBytes,
Start: match[0],
End: match[1],
Position: i + 1,
Type: detectTokenType(matchBytes),
}
rv[i] = &token
}
return rv
}
func RegexpTokenizerConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.Tokenizer, error) {
rval, ok := config["regexp"].(string)
if !ok {
return nil, fmt.Errorf("must specify regexp")
}
r, err := regexp.Compile(rval)
if err != nil {
return nil, fmt.Errorf("unable to build regexp tokenizer: %v", err)
}
return NewRegexpTokenizer(r), nil
}
func init() {
registry.RegisterTokenizer(Name, RegexpTokenizerConstructor)
}
func detectTokenType(termBytes []byte) analysis.TokenType {
if IdeographRegexp.Match(termBytes) {
return analysis.Ideographic
}
_, err := strconv.ParseFloat(string(termBytes), 64)
if err == nil {
return analysis.Numeric
}
return analysis.AlphaNumeric
}