Add functions to map iso code string to iso code enum (#44)

isocode.go

@@ -16,6 +16,8 @@
 
 package lingua
 
+import "strings"
+
 // IsoCode639_1 is the type used for enumerating the ISO 639-1 code
 // representations of the supported languages.
 //
@@ -487,3 +489,35 @@ const (
 	// UnknownIsoCode639_3 is the ISO 639-3 code for Unknown.
 	UnknownIsoCode639_3
 )
+
+// GetIsoCode639_1FromValue returns the ISO 639-1 code for the given name.
+func GetIsoCode639_1FromValue(name string) IsoCode639_1 {
+	if isoCodeEnum, ok := stringToIsoCode639_1[strings.ToLower(name)]; ok {
+		return isoCodeEnum
+	}
+	return UnknownIsoCode639_1
+}
+
+// GetIsoCode639_3FromValue returns the ISO 639-3 code for the given name.
+func GetIsoCode639_3FromValue(name string) IsoCode639_3 {
+	if isoCodeEnum, ok := stringToIsoCode639_3[strings.ToLower(name)]; ok {
+		return isoCodeEnum
+	}
+	return UnknownIsoCode639_3
+}
+
+var stringToIsoCode639_1 = func() map[string]IsoCode639_1 {
+	m := make(map[string]IsoCode639_1)
+	for isoCode := AF; isoCode <= ZU; isoCode++ {
+		m[strings.ToLower(isoCode.String())] = isoCode
+	}
+	return m
+}()
+
+var stringToIsoCode639_3 = func() map[string]IsoCode639_3 {
+	m := make(map[string]IsoCode639_3)
+	for isoCode := AFR; isoCode <= ZUL; isoCode++ {
+		m[strings.ToLower(isoCode.String())] = isoCode
+	}
+	return m
+}()

isocode_test.go

@@ -0,0 +1,40 @@
+/*
+ * Copyright © 2021-present Peter M. Stahl [email protected]
+ *
+ * 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 expressed or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package lingua
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestGetIsoCode639_1FromValue(t *testing.T) {
+	assert.Equal(t, AF, GetIsoCode639_1FromValue("AF"))
+	assert.Equal(t, AF, GetIsoCode639_1FromValue("af"))
+	assert.Equal(t, ZU, GetIsoCode639_1FromValue("ZU"))
+	assert.Equal(t, ZU, GetIsoCode639_1FromValue("zu"))
+	assert.Equal(t, UnknownIsoCode639_1, GetIsoCode639_1FromValue("xy"))
+	assert.Equal(t, UnknownIsoCode639_1, GetIsoCode639_1FromValue(""))
+}
+
+func TestGetIsoCode639_3FromValue(t *testing.T) {
+	assert.Equal(t, AFR, GetIsoCode639_3FromValue("AFR"))
+	assert.Equal(t, AFR, GetIsoCode639_3FromValue("afr"))
+	assert.Equal(t, ZUL, GetIsoCode639_3FromValue("ZUL"))
+	assert.Equal(t, ZUL, GetIsoCode639_3FromValue("zul"))
+	assert.Equal(t, UnknownIsoCode639_3, GetIsoCode639_3FromValue("xyz"))
+	assert.Equal(t, UnknownIsoCode639_3, GetIsoCode639_3FromValue(""))
+}

language.go

@@ -146,25 +146,25 @@ func AllLanguagesWithLatinScript() []Language {
 }
 
 // GetLanguageFromIsoCode639_1 returns the language for the given
-// ISO 639-1 code.
+// ISO 639-1 code enum value.
 func GetLanguageFromIsoCode639_1(isoCode IsoCode639_1) Language {
 	for _, language := range AllLanguages() {
 		if language.IsoCode639_1() == isoCode {
 			return language
 		}
 	}
-	return -1
+	return Unknown
 }
 
 // GetLanguageFromIsoCode639_3 returns the language for the given
-// ISO 639-3 code.
+// ISO 639-3 code enum value.
 func GetLanguageFromIsoCode639_3(isoCode IsoCode639_3) Language {
 	for _, language := range AllLanguages() {
 		if language.IsoCode639_3() == isoCode {
 			return language
 		}
 	}
-	return -1
+	return Unknown
 }
 
 func allLanguagesWithScript(script alphabet) (languages []Language) {

language_test.go

@@ -259,3 +259,15 @@ func TestAllLanguagesWithLatinScript(t *testing.T) {
 		},
 		AllLanguagesWithLatinScript())
 }
+
+func TestGetLanguageFromIsoCode639_1(t *testing.T) {
+	assert.Equal(t, Afrikaans, GetLanguageFromIsoCode639_1(AF))
+	assert.Equal(t, Zulu, GetLanguageFromIsoCode639_1(ZU))
+	assert.Equal(t, Unknown, GetLanguageFromIsoCode639_1(UnknownIsoCode639_1))
+}
+
+func TestGetLanguageFromIsoCode639_3(t *testing.T) {
+	assert.Equal(t, Afrikaans, GetLanguageFromIsoCode639_3(AFR))
+	assert.Equal(t, Zulu, GetLanguageFromIsoCode639_3(ZUL))
+	assert.Equal(t, Unknown, GetLanguageFromIsoCode639_3(UnknownIsoCode639_3))
+}