snapshot of https://github.com/blevesearch/bleve.git (master, 2026-09-15; blobs > 131072B omitted)

analysis/token/elision/elision.go

@@ -0,0 +1,77 @@
+//  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 elision
+
+import (
+	"fmt"
+	"unicode/utf8"
+
+	"github.com/blevesearch/bleve/v2/analysis"
+	"github.com/blevesearch/bleve/v2/registry"
+)
+
+const Name = "elision"
+
+const RightSingleQuotationMark = '’'
+const Apostrophe = '\''
+
+type ElisionFilter struct {
+	articles analysis.TokenMap
+}
+
+func NewElisionFilter(articles analysis.TokenMap) *ElisionFilter {
+	return &ElisionFilter{
+		articles: articles,
+	}
+}
+
+func (s *ElisionFilter) Filter(input analysis.TokenStream) analysis.TokenStream {
+	for _, token := range input {
+		term := token.Term
+		for i := 0; i < len(term); {
+			r, size := utf8.DecodeRune(term[i:])
+			if r == Apostrophe || r == RightSingleQuotationMark {
+				// see if the prefix matches one of the articles
+				prefix := term[0:i]
+				_, articleMatch := s.articles[string(prefix)]
+				if articleMatch {
+					token.Term = term[i+size:]
+					break
+				}
+			}
+			i += size
+		}
+	}
+	return input
+}
+
+func ElisionFilterConstructor(config map[string]interface{}, cache *registry.Cache) (analysis.TokenFilter, error) {
+	articlesTokenMapName, ok := config["articles_token_map"].(string)
+	if !ok {
+		return nil, fmt.Errorf("must specify articles_token_map")
+	}
+	articlesTokenMap, err := cache.TokenMapNamed(articlesTokenMapName)
+	if err != nil {
+		return nil, fmt.Errorf("error building elision filter: %v", err)
+	}
+	return NewElisionFilter(articlesTokenMap), nil
+}
+
+func init() {
+	err := registry.RegisterTokenFilter(Name, ElisionFilterConstructor)
+	if err != nil {
+		panic(err)
+	}
+}