added apostrophe filter to improve turkish analyzer

closes #27

analysis/token_filters/apostrophe_filter/apostrophe_filter.go

@@ -0,0 +1,41 @@
+//  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 apostrophe_filter
+
+import (
+	"bytes"
+
+	"github.com/couchbaselabs/bleve/analysis"
+)
+
+const RIGHT_SINGLE_QUOTATION_MARK = "’"
+const APOSTROPHE = "'"
+
+const APOSTROPHES = APOSTROPHE + RIGHT_SINGLE_QUOTATION_MARK
+
+type ApostropheFilter struct{}
+
+func NewApostropheFilter() *ApostropheFilter {
+	return &ApostropheFilter{}
+}
+
+func (s *ApostropheFilter) Filter(input analysis.TokenStream) analysis.TokenStream {
+	rv := make(analysis.TokenStream, 0)
+
+	for _, token := range input {
+		firstApostrophe := bytes.IndexAny(token.Term, APOSTROPHES)
+		if firstApostrophe >= 0 {
+			// found an apostrophe
+			token.Term = token.Term[0:firstApostrophe]
+		}
+		rv = append(rv, token)
+	}
+
+	return rv
+}

analysis/token_filters/apostrophe_filter/apostrophe_filter_test.go

@@ -0,0 +1,93 @@
+//  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 apostrophe_filter
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/couchbaselabs/bleve/analysis"
+)
+
+func TestApostropheFilter(t *testing.T) {
+
+	tests := []struct {
+		input  analysis.TokenStream
+		output analysis.TokenStream
+	}{
+		{
+			input: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("Türkiye'de"),
+				},
+			},
+			output: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("Türkiye"),
+				},
+			},
+		},
+		{
+			input: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("2003'te"),
+				},
+			},
+			output: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("2003"),
+				},
+			},
+		},
+		{
+			input: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("Van"),
+				},
+			},
+			output: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("Van"),
+				},
+			},
+		},
+		{
+			input: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("Gölü'nü"),
+				},
+			},
+			output: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("Gölü"),
+				},
+			},
+		},
+		{
+			input: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("gördüm"),
+				},
+			},
+			output: analysis.TokenStream{
+				&analysis.Token{
+					Term: []byte("gördüm"),
+				},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		apostropheFilter := NewApostropheFilter()
+		actual := apostropheFilter.Filter(test.input)
+		if !reflect.DeepEqual(actual, test.output) {
+			t.Errorf("expected %s, got %s", test.output[0].Term, actual[0].Term)
+		}
+	}
+}

config.go

@@ -23,6 +23,7 @@ import (
 	"github.com/couchbaselabs/bleve/analysis/tokenizers/single_token"
 	"github.com/couchbaselabs/bleve/analysis/tokenizers/unicode_word_boundary"
 
+	"github.com/couchbaselabs/bleve/analysis/token_filters/apostrophe_filter"
 	"github.com/couchbaselabs/bleve/analysis/token_filters/cld2"
 	"github.com/couchbaselabs/bleve/analysis/token_filters/elision_filter"
 	"github.com/couchbaselabs/bleve/analysis/token_filters/length_filter"
@@ -179,6 +180,9 @@ func init() {
 	Config.Analysis.TokenFilters["short"] = length_filter.NewLengthFilter(3, -1)
 	Config.Analysis.TokenFilters["long"] = length_filter.NewLengthFilter(-1, 255)
 	Config.Analysis.TokenFilters["to_lower"] = lower_case_filter.NewLowerCaseFilter()
+	Config.Analysis.TokenFilters["apostrophe"] = apostrophe_filter.NewApostropheFilter()
+
+	// register stemmer filters
 	Config.Analysis.TokenFilters["stemmer_da"] = stemmer_filter.MustNewStemmerFilter("danish")
 	Config.Analysis.TokenFilters["stemmer_nl"] = stemmer_filter.MustNewStemmerFilter("dutch")
 	Config.Analysis.TokenFilters["stemmer_en"] = stemmer_filter.MustNewStemmerFilter("english")
@@ -309,7 +313,7 @@ func init() {
 	Config.Analysis.Analyzers["es"] = spanishAnalyzer
 	swedishAnalyzer := Config.MustBuildNewAnalyzer([]string{}, "unicode", []string{"to_lower", "stop_token_sv", "stemmer_sv"})
 	Config.Analysis.Analyzers["sv"] = swedishAnalyzer
-	turkishAnalyzer := Config.MustBuildNewAnalyzer([]string{}, "unicode", []string{"to_lower", "stop_token_tr", "stemmer_tr"})
+	turkishAnalyzer := Config.MustBuildNewAnalyzer([]string{}, "unicode", []string{"apostrophe", "to_lower", "stop_token_tr", "stemmer_tr"})
 	Config.Analysis.Analyzers["tr"] = turkishAnalyzer
 	thaiAnalyzer := Config.MustBuildNewAnalyzer([]string{}, "unicode_th", []string{"to_lower", "stop_token_th"})
 	Config.Analysis.Analyzers["th"] = thaiAnalyzer