Add support for plural forms

gotext.go

@@ -79,15 +79,30 @@ func Configure(lib, lang, dom string) {
 }
 
 // Get uses the default domain globally set to return the corresponding translation of a given string.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
 func Get(str string, vars ...interface{}) string {
 	return GetD(domain, str, vars...)
 }
 
+// GetN retrieves the (N)th plural form translation for the given string in the "default" domain.
+// If n == 0, usually the singular form of the string is returned as defined in the PO file.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
+func GetN(str, plural string, n int, vars ...interface{}) string {
+	return GetND("default", str, plural, n, vars...)
+}
+
 // GetD returns the corresponding translation in the given domain for a given string.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
 func GetD(dom, str string, vars ...interface{}) string {
+	return GetND(dom, str, str, 0, vars...)
+}
+
+// GetND retrieves the (N)th plural form translation in the given domain for a given string.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
+func GetND(dom, str, plural string, n int, vars ...interface{}) string {
 	// Try to load default package Locale storage
 	loadStorage(false)
 
 	// Return translation
-	return storage.GetD(dom, str, vars...)
+	return storage.GetND(dom, str, plural, n, vars...)
 }

gotext_test.go

@@ -17,7 +17,10 @@ msgid "Another string"
 msgstr ""
 
 msgid "One with var: %s"
-msgstr "This one sets the var: %s"
+msgid_plural "Several with vars: %s"
+msgstr[0] "This one is the singular: %s"
+msgstr[1] "This one is the plural: %s"
+msgstr[2] "And this is the second plural form: %s"
 
     `
 
@@ -50,7 +53,13 @@ msgstr "This one sets the var: %s"
 
 	v := "Variable"
 	tr = Get("One with var: %s", v)
-	if tr != "This one sets the var: Variable" {
-		t.Errorf("Expected 'This one sets the var: Variable' but got '%s'", tr)
+	if tr != "This one is the singular: Variable" {
+		t.Errorf("Expected 'This one is the singular: Variable' but got '%s'", tr)
+	}
+
+	// Test plural
+	tr = GetN("One with var: %s", "Several with vars: %s", 2, v)
+	if tr != "And this is the second plural form: Variable" {
+		t.Errorf("Expected 'And this is the second plural form: Variable' but got '%s'", tr)
 	}
 }

locale.go

@@ -53,20 +53,35 @@ func (l *Locale) AddDomain(dom string) {
 }
 
 // Get uses a domain "default" to return the corresponding translation of a given string.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
 func (l *Locale) Get(str string, vars ...interface{}) string {
 	return l.GetD("default", str, vars...)
 }
 
+// GetN retrieves the (N)th plural form translation for the given string in the "default" domain.
+// If n == 0, usually the singular form of the string is returned as defined in the PO file.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
+func (l *Locale) GetN(str, plural string, n int, vars ...interface{}) string {
+	return l.GetND("default", str, plural, n, vars...)
+}
+
 // GetD returns the corresponding translation in the given domain for a given string.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
 func (l *Locale) GetD(dom, str string, vars ...interface{}) string {
+	return l.GetND(dom, str, str, 0, vars...)
+}
+
+// GetND retrieves the (N)th plural form translation in the given domain for a given string.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
+func (l *Locale) GetND(dom, str, plural string, n int, vars ...interface{}) string {
 	if l.domains != nil {
 		if _, ok := l.domains[dom]; ok {
 			if l.domains[dom] != nil {
-				return l.domains[dom].Get(str, vars...)
+				return l.domains[dom].GetN(str, plural, n, vars...)
 			}
 		}
 	}
 
 	// Return the same we received by default
-	return fmt.Sprintf(str, vars...)
+	return fmt.Sprintf(plural, vars...)
 }

locale_test.go

@@ -17,7 +17,10 @@ msgid "Another string"
 msgstr ""
 
 msgid "One with var: %s"
-msgstr "This one sets the var: %s"
+msgid_plural "Several with vars: %s"
+msgstr[0] "This one is the singular: %s"
+msgstr[1] "This one is the plural: %s"
+msgstr[2] "And this is the second plural form: %s"
 
     `
 
@@ -56,7 +59,13 @@ msgstr "This one sets the var: %s"
 
 	v := "Variable"
 	tr = l.GetD("my_domain", "One with var: %s", v)
-	if tr != "This one sets the var: Variable" {
-		t.Errorf("Expected 'This one sets the var: Variable' but got '%s'", tr)
+	if tr != "This one is the singular: Variable" {
+		t.Errorf("Expected 'This one is the singular: Variable' but got '%s'", tr)
+	}
+
+	// Test plural
+	tr = l.GetND("my_domain", "One with var: %s", "Several with vars: %s", 2, v)
+	if tr != "And this is the second plural form: Variable" {
+		t.Errorf("Expected 'And this is the second plural form: Variable' but got '%s'", tr)
 	}
 }

po.go

@@ -9,10 +9,44 @@ import (
 	"sync"
 )
 
+type translation struct {
+	id       string
+	pluralId string
+	trs      map[int]string
+}
+
+func newTranslation() *translation {
+	tr := new(translation)
+	tr.trs = make(map[int]string)
+
+	return tr
+}
+
+func (t *translation) get() string {
+	// Look for translation index 0
+	if _, ok := t.trs[0]; ok {
+		return t.trs[0]
+	}
+
+	// Return unstranlated id by default
+	return t.id
+}
+
+func (t *translation) getN(n int) string {
+	// Look for translation index
+	if _, ok := t.trs[n]; ok {
+		return t.trs[n]
+	}
+
+	// Return unstranlated plural by default
+	return t.pluralId
+}
+
+// Po type handles the content of any PO file.
 type Po struct {
-    // Storage
-	translations map[string]string
-	
+	// Storage
+	translations map[string]*translation
+
 	// Sync Mutex
 	sync.RWMutex
 }
@@ -41,16 +75,16 @@ func (po *Po) ParseFile(f string) {
 
 // Parse loads the translations specified in the provided string (str)
 func (po *Po) Parse(str string) {
-    po.Lock()
+	po.Lock()
 	defer po.Unlock()
-	
+
 	if po.translations == nil {
-		po.translations = make(map[string]string)
+		po.translations = make(map[string]*translation)
 	}
 
 	lines := strings.Split(str, "\n")
 
-	var msgid, msgstr string
+	tr := newTranslation()
 
 	for _, l := range lines {
 		// Trim spaces
@@ -62,35 +96,93 @@ func (po *Po) Parse(str string) {
 		}
 
 		// Skip invalid lines
-		if !strings.HasPrefix(l, "msgid") && !strings.HasPrefix(l, "msgstr") {
+		if !strings.HasPrefix(l, "msgid") && !strings.HasPrefix(l, "msgid_plural") && !strings.HasPrefix(l, "msgstr") {
 			continue
 		}
 
 		// Buffer msgid and continue
-		if strings.HasPrefix(l, "msgid") {
-			msgid = strings.TrimSpace(strings.TrimPrefix(l, "msgid"))
-			msgid, _ = strconv.Unquote(msgid)
+		if strings.HasPrefix(l, "msgid") && !strings.HasPrefix(l, "msgid_plural") {
+			// Save current translation buffer.
+			po.translations[tr.id] = tr
 
+			// Flush buffer
+			tr = newTranslation()
+
+			// Set id
+			tr.id, _ = strconv.Unquote(strings.TrimSpace(strings.TrimPrefix(l, "msgid")))
+
+			// Loop
 			continue
 		}
 
-		// Save translation for buffered msgid
-		if strings.HasPrefix(l, "msgstr") {
-			msgstr = strings.TrimSpace(strings.TrimPrefix(l, "msgstr"))
-			msgstr, _ = strconv.Unquote(msgstr)
+		// Check for plural form
+		if strings.HasPrefix(l, "msgid_plural") {
+			tr.pluralId, _ = strconv.Unquote(strings.TrimSpace(strings.TrimPrefix(l, "msgid_plural")))
 
-			po.translations[msgid] = msgstr
+			// Loop
+			continue
 		}
+
+		// Save translation
+		if strings.HasPrefix(l, "msgstr") {
+			l = strings.TrimSpace(strings.TrimPrefix(l, "msgstr"))
+
+			// Check for indexed translation forms
+			if strings.HasPrefix(l, "[") {
+				in := strings.Index(l, "]")
+				if in == -1 {
+					// Skip wrong index formatting
+					continue
+				}
+
+				// Parse index
+				i, err := strconv.Atoi(l[1:in])
+				if err != nil {
+					// Skip wrong index formatting
+					continue
+				}
+
+				// Parse translation string
+				tr.trs[i], _ = strconv.Unquote(strings.TrimSpace(l[in+1:]))
+
+				// Loop
+				continue
+			}
+
+			// Save single translation form under 0 index
+			tr.trs[0], _ = strconv.Unquote(l)
+		}
+	}
+
+	// Save last translation buffer.
+	if tr.id != "" {
+		po.translations[tr.id] = tr
 	}
 }
 
+// Get retrieves the corresponding translation for the given string.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
 func (po *Po) Get(str string, vars ...interface{}) string {
 	if po.translations != nil {
 		if _, ok := po.translations[str]; ok {
-			return fmt.Sprintf(po.translations[str], vars...)
+			return fmt.Sprintf(po.translations[str].get(), vars...)
 		}
 	}
 
 	// Return the same we received by default
 	return fmt.Sprintf(str, vars...)
 }
+
+// GetN retrieves the (N)th plural form translation for the given string.
+// If n == 0, usually the singular form of the string is returned as defined in the PO file.
+// Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
+func (po *Po) GetN(str, plural string, n int, vars ...interface{}) string {
+	if po.translations != nil {
+		if _, ok := po.translations[str]; ok {
+			return fmt.Sprintf(po.translations[str].getN(n), vars...)
+		}
+	}
+
+	// Return the plural string we received by default
+	return fmt.Sprintf(plural, vars...)
+}

po_test.go

@@ -17,7 +17,10 @@ msgid "Another string"
 msgstr ""
 
 msgid "One with var: %s"
-msgstr "This one sets the var: %s"
+msgid_plural "Several with vars: %s"
+msgstr[0] "This one is the singular: %s"
+msgstr[1] "This one is the plural: %s"
+msgstr[2] "And this is the second plural form: %s"
 
     `
 	// Write PO content to file
@@ -46,7 +49,13 @@ msgstr "This one sets the var: %s"
 
 	v := "Variable"
 	tr = po.Get("One with var: %s", v)
-	if tr != "This one sets the var: Variable" {
-		t.Errorf("Expected 'This one sets the var: Variable' but got '%s'", tr)
+	if tr != "This one is the singular: Variable" {
+		t.Errorf("Expected 'This one is the singular: Variable' but got '%s'", tr)
+	}
+
+	// Test plural
+	tr = po.GetN("One with var: %s", "Several with vars: %s", 2, v)
+	if tr != "And this is the second plural form: Variable" {
+		t.Errorf("Expected 'And this is the second plural form: Variable' but got '%s'", tr)
 	}
 }