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added support for .po files stored in a LC_MESSAGES subdir

.travis.yml

@@ -0,0 +1,7 @@
+language: go
+script: go test -v -race ./...
+
+go:
+  - 1.5
+  - 1.6
+  - tip

README.md

@@ -1,25 +1,37 @@
 [![GoDoc](https://godoc.org/github.com/leonelquinteros/gotext?status.svg)](https://godoc.org/github.com/leonelquinteros/gotext)
+[![Build Status](https://travis-ci.org/leonelquinteros/gotext.svg?branch=master)](https://travis-ci.org/leonelquinteros/gotext)
 
 # Gotext
 
-GNU gettext utilities for Go. 
+[GNU gettext utilities](https://www.gnu.org/software/gettext) for Go. 
 
-Version: [0.9.1](https://github.com/leonelquinteros/gotext/releases/tag/v0.9.1)
+Version: [v1.1.0](https://github.com/leonelquinteros/gotext/releases/tag/v1.1.0)
 
 
-#Features
+# Features
 
 - Implements GNU gettext support in native Go.
-- Safe for concurrent use across multiple goroutines. 
+- Complete support for [PO files](https://www.gnu.org/software/gettext/manual/html_node/PO-Files.html) including:
+  - Support for multiline strings and headers.
+  - Support for variables inside translation strings using Go's [fmt syntax](https://golang.org/pkg/fmt/).
+  - Support for [pluralization rules](https://www.gnu.org/software/gettext/manual/html_node/Translating-plural-forms.html).
+  - Support for [message contexts](https://www.gnu.org/software/gettext/manual/html_node/Contexts.html).
+- Thread-safe: This package is safe for concurrent use across multiple goroutines. 
 - It works with UTF-8 encoding as it's the default for Go language.
 - Unit tests available.
-- Language codes are automatically simplified from the form "en_UK" to "en" if the first isn't available.
+- Language codes are automatically simplified from the form `en_UK` to `en` if the first isn't available.
 - Ready to use inside Go templates.
-- Support for [pluralization rules](https://www.gnu.org/software/gettext/manual/html_node/Plural-forms.html).
-- Support for [message context](https://www.gnu.org/software/gettext/manual/html_node/Contexts.html).
-- Support for variables inside translation strings using Go's [fmt package syntax](https://golang.org/pkg/fmt/).
 
 
+# License
+
+[MIT license](LICENSE)
+
+
+# Documentation
+
+Refer to the Godoc package documentation at (https://godoc.org/github.com/leonelquinteros/gotext)
+
 
 # Installation 
 
@@ -32,14 +44,30 @@ go get github.com/leonelquinteros/gotext
 - No need for environment variables. Some naming conventions are applied but not needed.  
 
 
-# License
+#### Version vendoring
 
-[MIT license](LICENSE)
+Stable releases use [semantic versioning](http://semver.org/spec/v2.0.0.html) tagging on this repository.
+
+You can rely on this to use your preferred vendoring tool or to manually retrieve the corresponding release tag from the GitHub repository.
 
 
-# Documentation
+##### Vendoring with [gopkg.in](http://labix.org/gopkg.in)
 
-Refer to the Godoc package documentation at (https://godoc.org/github.com/leonelquinteros/gotext)
+[http://gopkg.in/leonelquinteros/gotext.v1](http://gopkg.in/leonelquinteros/gotext.v1)
+
+To get the latest v1 package stable release, execute:
+
+```
+go get gopkg.in/leonelquinteros/gotext.v1
+```
+
+To import this package, add the following line to your code:
+
+```go
+import "gopkg.in/leonelquinteros/gotext.v1"
+```
+
+Refer to it as gotext.
 
 
 # Locales directories structure
@@ -49,25 +77,29 @@ or to object constructors depending on the use, but either will use the same con
 
 Inside the base directory where will be the language directories named using the language and country 2-letter codes (en_US, es_AR, ...). 
 All package functions can lookup after the simplified version for each language in case the full code isn't present but the more general language code exists. 
-So if the language set is "en_UK", but there is no directory named after that code and there is a directory named "en", 
+So if the language set is `en_UK`, but there is no directory named after that code and there is a directory named `en`, 
 all package functions will be able to resolve this generalization and provide translations for the more general library.  
 
 The language codes are assumed to be [ISO 639-1](https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes) codes (2-letter codes). 
-That said, most functions will work with any coding standard as long the directory name matches the language code set on the configuration. 
+That said, most functions will work with any coding standard as long the directory name matches the language code set on the configuration.
 
-A normal library directory structure may look like: 
+Then, there can be a `LC_MESSAGES` containing all PO files or the PO files themselves.  
+A library directory structure can look like: 
 
 ```
 /path/to/locales
 /path/to/locales/en_US
-/path/to/locales/en_US/default.po
-/path/to/locales/en_US/extras.po
+/path/to/locales/en_US/LC_MESSAGES
+/path/to/locales/en_US/LC_MESSAGES/default.po
+/path/to/locales/en_US/LC_MESSAGES/extras.po
 /path/to/locales/en_UK
-/path/to/locales/en_UK/default.po
-/path/to/locales/en_UK/extras.po
+/path/to/locales/en_UK/LC_MESSAGES
+/path/to/locales/en_UK/LC_MESSAGES/default.po
+/path/to/locales/en_UK/LC_MESSAGES/extras.po
 /path/to/locales/en_AU
-/path/to/locales/en_AU/default.po
-/path/to/locales/en_AU/extras.po
+/path/to/locales/en_AU/LC_MESSAGES
+/path/to/locales/en_AU/LC_MESSAGES/default.po
+/path/to/locales/en_AU/LC_MESSAGES/extras.po
 /path/to/locales/es
 /path/to/locales/es/default.po
 /path/to/locales/es/extras.po
@@ -85,9 +117,9 @@ And so on...
 
 # About translation function names
 
-The standard GNU gettext defines helper functions that maps to the gettext() function and it's widely adopted by most implementations. 
+The standard GNU gettext defines helper functions that maps to the `gettext()` function and it's widely adopted by most implementations. 
 
-The basic translation function is usually _() in the form: 
+The basic translation function is usually `_()` in the form: 
 
 ```
 _("Translate this")
@@ -110,7 +142,7 @@ func _(str string, vars ...interface{}) string {
 
 This is valid and can be used within a package.
 
-In normal conditions the Go compiler will optimize the calls to _() by replacing its content in place of the function call to reduce the function calling overhead. 
+In normal conditions the Go compiler will optimize the calls to `_()` by replacing its content in place of the function call to reduce the function calling overhead. 
 This is a normal Go compiler behavior.  
 
 
@@ -226,6 +258,10 @@ msgstr "This one sets the var: %s"
 ## Use plural forms of translations
 
 PO format supports defining one or more plural forms for the same translation.
+Relying on the PO file headers, a Plural-Forms formula can be set on the translation file
+as defined in (https://www.gnu.org/savannah-checkouts/gnu/gettext/manual/html_node/Plural-forms.html)
+
+Plural formulas are parsed and evaluated using [Anko](https://github.com/mattn/anko)
 
 ```go
 import "github.com/leonelquinteros/gotext"
@@ -233,6 +269,12 @@ import "github.com/leonelquinteros/gotext"
 func main() {
     // Set PO content
     str := `
+msgid ""
+msgstr ""
+
+# Header below
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
+
 msgid "Translate this"
 msgstr "Translated text"
 
@@ -243,15 +285,14 @@ msgid "One with 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"
 `
     
     // Create Po object
     po := new(Po)
     po.Parse(str)
     
-    println(po.GetN("One with var: %s", "Several with vars: %s", 2, v))
-    // "And this is the second plural form: Variable"
+    println(po.GetN("One with var: %s", "Several with vars: %s", 54, v))
+    // "This one is the plural: Variable"
 }
 ```
 

gotext.go

@@ -1,8 +1,6 @@
 /*
 Package gotext implements GNU gettext utilities.
 
-Version 0.9.0 (stable)
-
 For quick/simple translations you can use the package level functions directly.
 
     import "github.com/leonelquinteros/gotext"
@@ -30,7 +28,7 @@ var (
 	language = "en_US"
 
 	// Path to library directory where all locale directories and translation files are.
-	library = "/tmp"
+	library = "/usr/local/share/locale"
 
 	// Storage for package level methods
 	storage *Locale
@@ -102,8 +100,7 @@ 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.
+// GetN retrieves the (N)th plural form of translation for the given string in the "default" domain.
 // 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...)
@@ -112,10 +109,10 @@ func GetN(str, plural string, n int, vars ...interface{}) string {
 // 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...)
+	return GetND(dom, str, str, 1, vars...)
 }
 
-// GetND retrieves the (N)th plural form translation in the given domain for a given string.
+// GetND retrieves the (N)th plural form of 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
@@ -131,8 +128,7 @@ func GetC(str, ctx string, vars ...interface{}) string {
 	return GetDC(domain, str, ctx, vars...)
 }
 
-// GetNC retrieves the (N)th plural form translation for the given string in the given context in the "default" domain.
-// If n == 0, usually the singular form of the string is returned as defined in the PO file.
+// GetNC retrieves the (N)th plural form of translation for the given string in the given context in the "default" domain.
 // Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
 func GetNC(str, plural string, n int, ctx string, vars ...interface{}) string {
 	return GetNDC("default", str, plural, n, ctx, vars...)
@@ -141,10 +137,10 @@ func GetNC(str, plural string, n int, ctx string, vars ...interface{}) string {
 // GetDC returns the corresponding translation in the given domain for the given string in the given context.
 // Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
 func GetDC(dom, str, ctx string, vars ...interface{}) string {
-	return GetNDC(dom, str, str, 0, ctx, vars...)
+	return GetNDC(dom, str, str, 1, ctx, vars...)
 }
 
-// GetNDC retrieves the (N)th plural form translation in the given domain for a given string.
+// GetNDC retrieves the (N)th plural form of 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 GetNDC(dom, str, plural string, n int, ctx string, vars ...interface{}) string {
 	// Try to load default package Locale storage

gotext_test.go

@@ -31,7 +31,17 @@ func TestGettersSetters(t *testing.T) {
 
 func TestPackageFunctions(t *testing.T) {
 	// Set PO content
-	str := `# Some comment
+	str := `
+msgid ""
+msgstr ""
+# Initial comment
+# Headers below
+"Language: en\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
+
+# Some comment
 msgid "My text"
 msgstr "Translated text"
 
@@ -109,8 +119,8 @@ msgstr "More translation"
 
 	// 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)
+	if tr != "This one is the plural: Variable" {
+		t.Errorf("Expected 'This one is the plural: Variable' but got '%s'", tr)
 	}
 
 	// Test context translations
@@ -125,7 +135,7 @@ msgstr "More translation"
 		t.Errorf("Expected 'This one is the singular in a Ctx context: Variable' but got '%s'", tr)
 	}
 
-	tr = GetNC("One with var: %s", "Several with vars: %s", 1, "Ctx", v)
+	tr = GetNC("One with var: %s", "Several with vars: %s", 19, "Ctx", v)
 	if tr != "This one is the plural in a Ctx context: Variable" {
 		t.Errorf("Expected 'This one is the plural in a Ctx context: Variable' but got '%s'", tr)
 	}

locale.go

@@ -20,13 +20,13 @@ Example:
         // Create Locale with library path and language code
         l := gotext.NewLocale("/path/to/i18n/dir", "en_US")
 
-        // Load domain '/path/to/i18n/dir/en_US/default.po'
+        // Load domain '/path/to/i18n/dir/en_US/LC_MESSAGES/default.po'
         l.AddDomain("default")
 
         // Translate text from default domain
         println(l.Get("Translate this"))
 
-        // Load different domain ('/path/to/i18n/dir/en_US/extras.po')
+        // Load different domain ('/path/to/i18n/dir/en_US/LC_MESSAGES/extras.po')
         l.AddDomain("extras")
 
         // Translate text from domain
@@ -58,23 +58,38 @@ func NewLocale(p, l string) *Locale {
 	}
 }
 
+func (l *Locale) findPO(dom string) string {
+	filename := path.Join(l.path, l.lang, "LC_MESSAGES", dom+".po")
+	if _, err := os.Stat(filename); err == nil {
+		return filename
+	}
+
+	if len(l.lang) > 2 {
+		filename = path.Join(l.path, l.lang[:2], "LC_MESSAGES", dom+".po")
+		if _, err := os.Stat(filename); err == nil {
+			return filename
+		}
+	}
+
+	filename = path.Join(l.path, l.lang, dom+".po")
+	if _, err := os.Stat(filename); err == nil {
+		return filename
+	}
+
+	if len(l.lang) > 2 {
+		filename = path.Join(l.path, l.lang[:2], dom+".po")
+	}
+
+	return filename
+}
+
 // AddDomain creates a new domain for a given locale object and initializes the Po object.
 // If the domain exists, it gets reloaded.
 func (l *Locale) AddDomain(dom string) {
 	po := new(Po)
 
-	// Check for file.
-	filename := path.Clean(l.path + string(os.PathSeparator) + l.lang + string(os.PathSeparator) + dom + ".po")
-
-	// Try to use the generic language dir if the provided isn't available
-	if _, err := os.Stat(filename); err != nil {
-		if len(l.lang) > 2 {
-			filename = path.Clean(l.path + string(os.PathSeparator) + l.lang[:2] + string(os.PathSeparator) + dom + ".po")
-		}
-	}
-
 	// Parse file.
-	po.ParseFile(filename)
+	po.ParseFile(l.findPO(dom))
 
 	// Save new domain
 	l.Lock()
@@ -92,8 +107,7 @@ 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.
+// GetN retrieves the (N)th plural form of translation for the given string in the "default" domain.
 // 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...)
@@ -102,11 +116,10 @@ func (l *Locale) GetN(str, plural string, n int, vars ...interface{}) string {
 // GetD returns the corresponding translation in the given domain for the 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...)
+	return l.GetND(dom, str, str, 1, vars...)
 }
 
-// GetND retrieves the (N)th plural form translation in the given domain for the given string.
-// If n == 0, usually the singular form of the string is returned as defined in the PO file.
+// GetND retrieves the (N)th plural form of translation in the given domain for the 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 {
 	// Sync read
@@ -131,8 +144,7 @@ func (l *Locale) GetC(str, ctx string, vars ...interface{}) string {
 	return l.GetDC("default", str, ctx, vars...)
 }
 
-// GetNC retrieves the (N)th plural form translation for the given string in the given context in the "default" domain.
-// If n == 0, usually the singular form of the string is returned as defined in the PO file.
+// GetNC retrieves the (N)th plural form of translation for the given string in the given context in the "default" domain.
 // Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
 func (l *Locale) GetNC(str, plural string, n int, ctx string, vars ...interface{}) string {
 	return l.GetNDC("default", str, plural, n, ctx, vars...)
@@ -141,11 +153,10 @@ func (l *Locale) GetNC(str, plural string, n int, ctx string, vars ...interface{
 // GetDC returns the corresponding translation in the given domain for the given string in the given context.
 // Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
 func (l *Locale) GetDC(dom, str, ctx string, vars ...interface{}) string {
-	return l.GetNDC(dom, str, str, 0, ctx, vars...)
+	return l.GetNDC(dom, str, str, 1, ctx, vars...)
 }
 
-// GetNDC retrieves the (N)th plural form translation in the given domain for the given string in the given context.
-// If n == 0, usually the singular form of the string is returned as defined in the PO file.
+// GetNDC retrieves the (N)th plural form of translation in the given domain for the given string in the given context.
 // Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
 func (l *Locale) GetNDC(dom, str, plural string, n int, ctx string, vars ...interface{}) string {
 	// Sync read

locale_test.go

@@ -8,7 +8,17 @@ import (
 
 func TestLocale(t *testing.T) {
 	// Set PO content
-	str := `# Some comment
+	str := `
+msgid ""
+msgstr ""
+# Initial comment
+# Headers below
+"Language: en\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
+
+# Some comment
 msgid "My text"
 msgstr "Translated text"
 
@@ -49,14 +59,14 @@ msgstr "More translation"
     `
 
 	// Create Locales directory with simplified language code
-	dirname := path.Clean("/tmp" + string(os.PathSeparator) + "en")
+	dirname := path.Join("/tmp", "en", "LC_MESSAGES")
 	err := os.MkdirAll(dirname, os.ModePerm)
 	if err != nil {
 		t.Fatalf("Can't create test directory: %s", err.Error())
 	}
 
 	// Write PO content to file
-	filename := path.Clean(dirname + string(os.PathSeparator) + "my_domain.po")
+	filename := path.Join(dirname, "my_domain.po")
 
 	f, err := os.Create(filename)
 	if err != nil {
@@ -91,9 +101,9 @@ msgstr "More translation"
 	}
 
 	// 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)
+	tr = l.GetND("my_domain", "One with var: %s", "Several with vars: %s", 7, v)
+	if tr != "This one is the plural: Variable" {
+		t.Errorf("Expected 'This one is the plural: Variable' but got '%s'", tr)
 	}
 
 	// Test non-existent "deafult" domain responses
@@ -137,7 +147,7 @@ msgstr "More translation"
 	}
 
 	// Test plural
-	tr = l.GetNDC("my_domain", "One with var: %s", "Several with vars: %s", 1, "Ctx", v)
+	tr = l.GetNDC("my_domain", "One with var: %s", "Several with vars: %s", 3, "Ctx", v)
 	if tr != "This one is the plural in a Ctx context: Test" {
 		t.Errorf("Expected 'This one is the plural in a Ctx context: Test' but got '%s'", tr)
 	}
@@ -168,14 +178,14 @@ msgstr[2] "And this is the second plural form: %s"
     `
 
 	// Create Locales directory with simplified language code
-	dirname := path.Clean("/tmp" + string(os.PathSeparator) + "es")
+	dirname := path.Join("/tmp", "es")
 	err := os.MkdirAll(dirname, os.ModePerm)
 	if err != nil {
 		t.Fatalf("Can't create test directory: %s", err.Error())
 	}
 
 	// Write PO content to file
-	filename := path.Clean(dirname + string(os.PathSeparator) + "race.po")
+	filename := path.Join(dirname, "race.po")
 
 	f, err := os.Create(filename)
 	if err != nil {

po.go

@@ -1,8 +1,11 @@
 package gotext
 
 import (
+	"bufio"
 	"fmt"
+	"github.com/leonelquinteros/anko/vm"
 	"io/ioutil"
+	"net/textproto"
 	"os"
 	"strconv"
 	"strings"
@@ -44,8 +47,8 @@ func (t *translation) getN(n int) string {
 
 /*
 Po parses the content of any PO file and provides all the translation functions needed.
-It's the base object used by all packafe methods.
-And it's safe for concurrent use by multiple goroutines by using the sync package for write locking.
+It's the base object used by all package methods.
+And it's safe for concurrent use by multiple goroutines by using the sync package for locking.
 
 Example:
 
@@ -64,6 +67,19 @@ Example:
 
 */
 type Po struct {
+	// Headers
+	RawHeaders string
+
+	// Language header
+	Language string
+
+	// Plural-Forms header
+	PluralForms string
+
+	// Parsed Plural-Forms header values
+	nplurals int
+	plural   string
+
 	// Storage
 	translations map[string]*translation
 	contexts     map[string]map[string]*translation
@@ -96,12 +112,14 @@ func (po *Po) ParseFile(f string) {
 
 // Parse loads the translations specified in the provided string (str)
 func (po *Po) Parse(str string) {
+	// Lock while parsing
+	po.Lock()
+	defer po.Unlock()
+
 	// Init storage
 	if po.translations == nil {
-		po.Lock()
 		po.translations = make(map[string]*translation)
 		po.contexts = make(map[string]map[string]*translation)
-		po.Unlock()
 	}
 
 	// Get lines
@@ -123,14 +141,13 @@ func (po *Po) Parse(str string) {
 		}
 
 		// Skip invalid lines
-		if !strings.HasPrefix(l, "msgctxt") && !strings.HasPrefix(l, "msgid") && !strings.HasPrefix(l, "msgid_plural") && !strings.HasPrefix(l, "msgstr") {
+		if !strings.HasPrefix(l, "\"") && !strings.HasPrefix(l, "msgctxt") && !strings.HasPrefix(l, "msgid") && !strings.HasPrefix(l, "msgid_plural") && !strings.HasPrefix(l, "msgstr") {
 			continue
 		}
 
 		// Buffer context and continue
 		if strings.HasPrefix(l, "msgctxt") {
 			// Save current translation buffer.
-			po.Lock()
 			// No context
 			if ctx == "" {
 				po.translations[tr.id] = tr
@@ -141,7 +158,6 @@ func (po *Po) Parse(str string) {
 				}
 				po.contexts[ctx][tr.id] = tr
 			}
-			po.Unlock()
 
 			// Flush buffer
 			tr = newTranslation()
@@ -158,9 +174,7 @@ func (po *Po) Parse(str string) {
 		if strings.HasPrefix(l, "msgid") && !strings.HasPrefix(l, "msgid_plural") {
 			// Save current translation buffer if not inside a context.
 			if ctx == "" {
-				po.Lock()
 				po.translations[tr.id] = tr
-				po.Unlock()
 
 				// Flush buffer
 				tr = newTranslation()
@@ -198,21 +212,21 @@ func (po *Po) Parse(str string) {
 
 			// Check for indexed translation forms
 			if strings.HasPrefix(l, "[") {
-				in := strings.Index(l, "]")
-				if in == -1 {
+				idx := strings.Index(l, "]")
+				if idx == -1 {
 					// Skip wrong index formatting
 					continue
 				}
 
 				// Parse index
-				i, err := strconv.Atoi(l[1:in])
+				i, err := strconv.Atoi(l[1:idx])
 				if err != nil {
 					// Skip wrong index formatting
 					continue
 				}
 
 				// Parse translation string
-				tr.trs[i], _ = strconv.Unquote(strings.TrimSpace(l[in+1:]))
+				tr.trs[i], _ = strconv.Unquote(strings.TrimSpace(l[idx+1:]))
 
 				// Loop
 				continue
@@ -220,12 +234,36 @@ func (po *Po) Parse(str string) {
 
 			// Save single translation form under 0 index
 			tr.trs[0], _ = strconv.Unquote(l)
+
+			// Loop
+			continue
+		}
+
+		// Multi line strings and headers
+		if strings.HasPrefix(l, "\"") && strings.HasSuffix(l, "\"") {
+			// Check for multiline from previously set msgid
+			if tr.id != "" {
+				// Append to last translation found
+				uq, _ := strconv.Unquote(l)
+				tr.trs[len(tr.trs)-1] += uq
+
+				// Loop
+				continue
+			}
+
+			// Otherwise is a header
+			h, err := strconv.Unquote(strings.TrimSpace(l))
+			if err != nil {
+				continue
+			}
+
+			po.RawHeaders += h
+			continue
 		}
 	}
 
 	// Save last translation buffer.
 	if tr.id != "" {
-		po.Lock()
 		if ctx == "" {
 			po.translations[tr.id] = tr
 		} else {
@@ -235,8 +273,83 @@ func (po *Po) Parse(str string) {
 			}
 			po.contexts[ctx][tr.id] = tr
 		}
-		po.Unlock()
 	}
+
+	// Parse headers
+	po.RawHeaders += "\n\n"
+
+	reader := bufio.NewReader(strings.NewReader(po.RawHeaders))
+	tp := textproto.NewReader(reader)
+
+	mimeHeader, err := tp.ReadMIMEHeader()
+	if err != nil {
+		return
+	}
+
+	// Get/save needed headers
+	po.Language = mimeHeader.Get("Language")
+	po.PluralForms = mimeHeader.Get("Plural-Forms")
+
+	// Parse Plural-Forms formula
+	if po.PluralForms == "" {
+		return
+	}
+
+	// Split plural form header value
+	pfs := strings.Split(po.PluralForms, ";")
+
+	// Parse values
+	for _, i := range pfs {
+		vs := strings.SplitN(i, "=", 2)
+		if len(vs) != 2 {
+			continue
+		}
+
+		switch strings.TrimSpace(vs[0]) {
+		case "nplurals":
+			po.nplurals, _ = strconv.Atoi(vs[1])
+
+		case "plural":
+			po.plural = vs[1]
+		}
+	}
+}
+
+// pluralForm calculates the plural form index corresponding to n.
+// Returns 0 on error
+func (po *Po) pluralForm(n int) int {
+	po.RLock()
+	defer po.RUnlock()
+
+	// Failsafe
+	if po.nplurals < 1 {
+		return 0
+	}
+	if po.plural == "" {
+		return 0
+	}
+
+	// Init compiler
+	env := vm.NewEnv()
+	env.Define("n", n)
+
+	plural, err := env.Execute(po.plural)
+	if err != nil {
+		return 0
+	}
+	if plural.Type().Name() == "bool" {
+		if plural.Bool() {
+			return 1
+		} else {
+			return 0
+		}
+	}
+
+	if int(plural.Int()) > po.nplurals {
+		return 0
+	}
+
+	return int(plural.Int())
 }
 
 // Get retrieves the corresponding translation for the given string.
@@ -256,8 +369,7 @@ func (po *Po) Get(str string, vars ...interface{}) string {
 	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.
+// GetN retrieves the (N)th plural form of 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) GetN(str, plural string, n int, vars ...interface{}) string {
 	// Sync read
@@ -266,7 +378,7 @@ 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 fmt.Sprintf(po.translations[str].getN(po.pluralForm(n)), vars...)
 		}
 	}
 
@@ -295,8 +407,7 @@ func (po *Po) GetC(str, ctx string, vars ...interface{}) string {
 	return fmt.Sprintf(str, vars...)
 }
 
-// GetNC retrieves the (N)th plural form translation for the given string in the given context.
-// If n == 0, usually the singular form of the string is returned as defined in the PO file.
+// GetNC retrieves the (N)th plural form of translation for the given string in the given context.
 // Supports optional parameters (vars... interface{}) to be inserted on the formatted string using the fmt.Printf syntax.
 func (po *Po) GetNC(str, plural string, n int, ctx string, vars ...interface{}) string {
 	// Sync read
@@ -307,7 +418,7 @@ func (po *Po) GetNC(str, plural string, n int, ctx string, vars ...interface{})
 		if _, ok := po.contexts[ctx]; ok {
 			if po.contexts[ctx] != nil {
 				if _, ok := po.contexts[ctx][str]; ok {
-					return fmt.Sprintf(po.contexts[ctx][str].getN(n), vars...)
+					return fmt.Sprintf(po.contexts[ctx][str].getN(po.pluralForm(n)), vars...)
 				}
 			}
 		}

po_test.go

@@ -8,7 +8,17 @@ import (
 
 func TestPo(t *testing.T) {
 	// Set PO content
-	str := `# Some comment
+	str := `
+msgid ""
+msgstr ""
+# Initial comment
+# Headers below
+"Language: en\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
+
+# Some comment
 msgid "My text"
 msgstr "Translated text"
 
@@ -16,6 +26,11 @@ msgstr "Translated text"
 msgid "Another string"
 msgstr ""
 
+#Multi-line string
+msgid "Multi-line"
+msgstr "Multi "
+"line"
+
 msgid "One with var: %s"
 msgid_plural "Several with vars: %s"
 msgstr[0] "This one is the singular: %s"
@@ -82,10 +97,16 @@ msgstr "More translation"
 		t.Errorf("Expected 'This one is the singular: Variable' but got '%s'", tr)
 	}
 
+	// Test multi-line
+	tr = po.Get("Multi-line")
+	if tr != "Multi line" {
+		t.Errorf("Expected 'Multi line' 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)
+	if tr != "This one is the plural: Variable" {
+		t.Errorf("Expected 'This one is the plural: Variable' but got '%s'", tr)
 	}
 
 	// Test inexistent translations
@@ -94,7 +115,7 @@ msgstr "More translation"
 		t.Errorf("Expected 'This is a test' but got '%s'", tr)
 	}
 
-	tr = po.GetN("This is a test", "This are tests", 1)
+	tr = po.GetN("This is a test", "This are tests", 100)
 	if tr != "This are tests" {
 		t.Errorf("Expected 'This are tests' but got '%s'", tr)
 	}
@@ -105,7 +126,7 @@ msgstr "More translation"
 		t.Errorf("Expected '' but got '%s'", tr)
 	}
 
-	tr = po.GetN("This one has invalid syntax translations", "This are tests", 1)
+	tr = po.GetN("This one has invalid syntax translations", "This are tests", 4)
 	if tr != "Plural index" {
 		t.Errorf("Expected 'Plural index' but got '%s'", tr)
 	}
@@ -118,7 +139,7 @@ msgstr "More translation"
 	}
 
 	// Test plural
-	tr = po.GetNC("One with var: %s", "Several with vars: %s", 1, "Ctx", v)
+	tr = po.GetNC("One with var: %s", "Several with vars: %s", 17, "Ctx", v)
 	if tr != "This one is the plural in a Ctx context: Test" {
 		t.Errorf("Expected 'This one is the plural in a Ctx context: Test' but got '%s'", tr)
 	}
@@ -131,6 +152,210 @@ msgstr "More translation"
 
 }
 
+func TestPoHeaders(t *testing.T) {
+	// Set PO content
+	str := `
+msgid ""
+msgstr ""
+# Initial comment
+# Headers below
+"Language: en\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);\n"
+
+# Some comment
+msgid "Example"
+msgstr "Translated example"
+    `
+
+	// Create po object
+	po := new(Po)
+
+	// Parse
+	po.Parse(str)
+
+	// Check headers expected
+	if po.Language != "en" {
+		t.Errorf("Expected 'Language: en' but got '%s'", po.Language)
+	}
+
+	// Check headers expected
+	if po.PluralForms != "nplurals=2; plural=(n != 1);" {
+		t.Errorf("Expected 'Plural-Forms: nplurals=2; plural=(n != 1);' but got '%s'", po.PluralForms)
+	}
+}
+
+func TestPluralForms(t *testing.T) {
+	// Single form
+	str := `
+"Plural-Forms: nplurals=1; plural=0;"
+
+# Some comment
+msgid "Singular"
+msgid_plural "Plural"
+msgstr[0] "Singular form"
+msgstr[1] "Plural form 1"
+msgstr[2] "Plural form 2"
+msgstr[3] "Plural form 3"
+    `
+
+	// Create po object
+	po := new(Po)
+
+	// Parse
+	po.Parse(str)
+
+	// Check plural form
+	n := po.pluralForm(0)
+	if n != 0 {
+		t.Errorf("Expected 0 for pluralForm(0), got %d", n)
+	}
+	n = po.pluralForm(1)
+	if n != 0 {
+		t.Errorf("Expected 0 for pluralForm(1), got %d", n)
+	}
+	n = po.pluralForm(2)
+	if n != 0 {
+		t.Errorf("Expected 0 for pluralForm(2), got %d", n)
+	}
+	n = po.pluralForm(3)
+	if n != 0 {
+		t.Errorf("Expected 0 for pluralForm(3), got %d", n)
+	}
+	n = po.pluralForm(50)
+	if n != 0 {
+		t.Errorf("Expected 0 for pluralForm(50), got %d", n)
+	}
+
+	// ------------------------------------------------------------------------
+	// 2 forms
+	str = `
+"Plural-Forms: nplurals=2; plural=n != 1;"
+
+# Some comment
+msgid "Singular"
+msgid_plural "Plural"
+msgstr[0] "Singular form"
+msgstr[1] "Plural form 1"
+msgstr[2] "Plural form 2"
+msgstr[3] "Plural form 3"
+    `
+
+	// Create po object
+	po = new(Po)
+
+	// Parse
+	po.Parse(str)
+
+	// Check plural form
+	n = po.pluralForm(0)
+	if n != 1 {
+		t.Errorf("Expected 1 for pluralForm(0), got %d", n)
+	}
+	n = po.pluralForm(1)
+	if n != 0 {
+		t.Errorf("Expected 0 for pluralForm(1), got %d", n)
+	}
+	n = po.pluralForm(2)
+	if n != 1 {
+		t.Errorf("Expected 1 for pluralForm(2), got %d", n)
+	}
+	n = po.pluralForm(3)
+	if n != 1 {
+		t.Errorf("Expected 1 for pluralForm(3), got %d", n)
+	}
+
+	// ------------------------------------------------------------------------
+	// 3 forms
+	str = `
+"Plural-Forms: nplurals=3; plural=n%10==1 && n%100!=11 ? 0 : n != 0 ? 1 : 2;"
+
+# Some comment
+msgid "Singular"
+msgid_plural "Plural"
+msgstr[0] "Singular form"
+msgstr[1] "Plural form 1"
+msgstr[2] "Plural form 2"
+msgstr[3] "Plural form 3"
+    `
+
+	// Create po object
+	po = new(Po)
+
+	// Parse
+	po.Parse(str)
+
+	// Check plural form
+	n = po.pluralForm(0)
+	if n != 2 {
+		t.Errorf("Expected 2 for pluralForm(0), got %d", n)
+	}
+	n = po.pluralForm(1)
+	if n != 0 {
+		t.Errorf("Expected 0 for pluralForm(1), got %d", n)
+	}
+	n = po.pluralForm(2)
+	if n != 1 {
+		t.Errorf("Expected 1 for pluralForm(2), got %d", n)
+	}
+	n = po.pluralForm(3)
+	if n != 1 {
+		t.Errorf("Expected 1 for pluralForm(3), got %d", n)
+	}
+	n = po.pluralForm(100)
+	if n != 1 {
+		t.Errorf("Expected 1 for pluralForm(100), got %d", n)
+	}
+	n = po.pluralForm(49)
+	if n != 1 {
+		t.Errorf("Expected 1 for pluralForm(3), got %d", n)
+	}
+
+	// ------------------------------------------------------------------------
+	// 3 forms special
+	str = `
+"Plural-Forms: nplurals=3;"
+"plural=(n==1) ? 0 : (n>=2 && n<=4) ? 1 : 2;"
+
+# Some comment
+msgid "Singular"
+msgid_plural "Plural"
+msgstr[0] "Singular form"
+msgstr[1] "Plural form 1"
+msgstr[2] "Plural form 2"
+msgstr[3] "Plural form 3"
+    `
+
+	// Create po object
+	po = new(Po)
+
+	// Parse
+	po.Parse(str)
+
+	// Check plural form
+	n = po.pluralForm(1)
+	if n != 0 {
+		t.Errorf("Expected 0 for pluralForm(1), got %d", n)
+	}
+	n = po.pluralForm(2)
+	if n != 1 {
+		t.Errorf("Expected 1 for pluralForm(2), got %d", n)
+	}
+	n = po.pluralForm(4)
+	if n != 1 {
+		t.Errorf("Expected 4 for pluralForm(4), got %d", n)
+	}
+	n = po.pluralForm(0)
+	if n != 2 {
+		t.Errorf("Expected 2 for pluralForm(2), got %d", n)
+	}
+	n = po.pluralForm(1000)
+	if n != 2 {
+		t.Errorf("Expected 2 for pluralForm(1000), got %d", n)
+	}
+}
+
 func TestTranslationObject(t *testing.T) {
 	tr := newTranslation()
 	str := tr.get()