Add TOML support (#66)v1.8.0

Fixes #61
Updates https://github.com/spf13/hugo/issues/3200
Updates https://github.com/spf13/hugo/issues/2577

10 files changed, 140 insertions, 80 deletions

diff --git a/README.md b/README.md
index e607509..7136dc8 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@ go-i18n is a Go [package](#i18n-package) and a [command](#goi18n-command) that h
 * Supports [pluralized strings](http://cldr.unicode.org/index/cldr-spec/plural-rules) for all 200+ languages in the [Unicode Common Locale Data Repository (CLDR)](http://www.unicode.org/cldr/charts/28/supplemental/language_plural_rules.html).
   *  Code and tests are [automatically generated](https://github.com/nicksnyder/go-i18n/tree/master/i18n/language/codegen) from [CLDR data](http://cldr.unicode.org/index/downloads)
 * Supports strings with named variables using [text/template](http://golang.org/pkg/text/template/) syntax.
-* Translation files are simple JSON or YAML.
+* Translation files are simple JSON, TOML or YAML.
 * [Documented](http://godoc.org/github.com/nicksnyder/go-i18n) and [tested](https://travis-ci.org/nicksnyder/go-i18n)!
 
 Package i18n [![GoDoc](http://godoc.org/github.com/nicksnyder/go-i18n?status.svg)](http://godoc.org/github.com/nicksnyder/go-i18n/i18n)
@@ -118,6 +118,10 @@ Here is an example of the default file format that go-i18n supports:
 
 To use a different file format, write a parser for the format and add the parsed translations using [AddTranslation](https://godoc.org/github.com/nicksnyder/go-i18n/i18n#AddTranslation).
 
+Note that TOML only supports the flat format, which is described below.
+
+More examples of translation files: [JSON](https://github.com/nicksnyder/go-i18n/tree/master/goi18n/testdata/input), [TOML](https://github.com/nicksnyder/go-i18n/blob/master/goi18n/testdata/input/flat/ar-ar.one.toml), [YAML](https://github.com/nicksnyder/go-i18n/blob/master/goi18n/testdata/input/yaml/en-us.one.yaml).
+
 Flat Format
 -------------
 
@@ -166,6 +170,8 @@ and name of substructures (ids) should be always a string.
 If there is only one key in substructure and it is "other", then it's non-plural
 translation, else plural.
 
+More examples of flat format translation files can be found in [goi18n/testdata/input/flat](https://github.com/nicksnyder/go-i18n/tree/master/goi18n/testdata/input/flat).
+
 Contributions
 -------------
 
diff --git a/goi18n/merge_command.go b/goi18n/merge_command.go
index 184343e..1b9d04f 100644
--- a/goi18n/merge_command.go
+++ b/goi18n/merge_command.go
@@ -14,6 +14,7 @@ import (
 	"github.com/nicksnyder/go-i18n/i18n/bundle"
 	"github.com/nicksnyder/go-i18n/i18n/language"
 	"github.com/nicksnyder/go-i18n/i18n/translation"
+	toml "github.com/pelletier/go-toml"
 )
 
 type mergeCommand struct {
@@ -36,7 +37,7 @@ func (mc *mergeCommand) execute() error {
 	bundle := bundle.New()
 	for _, tf := range mc.translationFiles {
 		if err := bundle.LoadTranslationFile(tf); err != nil {
-			return fmt.Errorf("failed to load translation file %s because %s\n", tf, err)
+			return fmt.Errorf("failed to load translation file %s: %s\n", tf, err)
 		}
 	}
 
@@ -91,7 +92,11 @@ func (mc *mergeCommand) parse(arguments []string) {
 	mc.sourceLanguage = *sourceLanguage
 	mc.outdir = *outdir
 	mc.format = *format
-	mc.flat = *flat
+	if *format == "toml" {
+		mc.flat = true
+	} else {
+		mc.flat = *flat
+	}
 }
 
 func (mc *mergeCommand) SetArgs(args []string) {
@@ -110,13 +115,13 @@ func (mc *mergeCommand) writeFile(label string, translations []translation.Trans
 
 	buf, err := mc.marshal(convert(translations))
 	if err != nil {
-		return fmt.Errorf("failed to marshal %s strings to %s because %s", localeID, mc.format, err)
+		return fmt.Errorf("failed to marshal %s strings to %s: %s", localeID, mc.format, err)
 	}
 
 	filename := filepath.Join(mc.outdir, fmt.Sprintf("%s.%s.%s", localeID, label, mc.format))
 
 	if err := ioutil.WriteFile(filename, buf, 0666); err != nil {
-		return fmt.Errorf("failed to write %s because %s", filename, err)
+		return fmt.Errorf("failed to write %s: %s", filename, err)
 	}
 	return nil
 }
@@ -152,12 +157,27 @@ func (mc mergeCommand) marshal(v interface{}) ([]byte, error) {
 	switch mc.format {
 	case "json":
 		return json.MarshalIndent(v, "", "  ")
+	case "toml":
+		return marshalTOML(v)
 	case "yaml":
 		return yaml.Marshal(v)
 	}
 	return nil, fmt.Errorf("unsupported format: %s\n", mc.format)
 }
 
+func marshalTOML(v interface{}) ([]byte, error) {
+	m, ok := v.(map[string]interface{})
+	if !ok {
+		return nil, fmt.Errorf("invalid format for marshaling to TOML")
+	}
+	tree, err := toml.TreeFromMap(m)
+	if err != nil {
+		return nil, err
+	}
+	s, err := tree.ToTomlString()
+	return []byte(s), err
+}
+
 func usageMerge() {
 	fmt.Printf(`Merge translation files.
 
@@ -207,11 +227,12 @@ Options:
 
     -format format
         goi18n encodes the output translation files in this format.
-        Supported formats: json, yaml
+        Supported formats: json, toml, yaml
         Default: json
 
     -flat
         goi18n writes the output translation files in flat format.
+        Usage of '-format toml' automitically sets this flag.
         Default: true
 
 `)
diff --git a/goi18n/merge_command_flat_test.go b/goi18n/merge_command_flat_test.go
index 614785e..caa892d 100644
--- a/goi18n/merge_command_flat_test.go
+++ b/goi18n/merge_command_flat_test.go
@@ -2,12 +2,12 @@ package main
 
 import "testing"
 
-func TestMergeExecuteFlatJSON(t *testing.T) {
+func TestMergeExecuteFlat(t *testing.T) {
 	files := []string{
-		"testdata/input/flat/en-us.one.json",
+		"testdata/input/flat/en-us.one.yaml",
 		"testdata/input/flat/en-us.two.json",
 		"testdata/input/flat/fr-fr.json",
-		"testdata/input/flat/ar-ar.one.json",
+		"testdata/input/flat/ar-ar.one.toml",
 		"testdata/input/flat/ar-ar.two.json",
 	}
 	testFlatMergeExecute(t, files)
diff --git a/goi18n/testdata/en-us.flat.toml b/goi18n/testdata/en-us.flat.toml
new file mode 100644
index 0000000..5623a6c
--- /dev/null
+++ b/goi18n/testdata/en-us.flat.toml
@@ -0,0 +1,25 @@
+[program_greeting]
+other = "Hello world"
+
+[person_greeting]
+other = "Hello {{.Person}}"
+
+[my_height_in_meters]
+one = "I am {{.Count}} meter tall."
+other = "I am {{.Count}} meters tall."
+
+[your_unread_email_count]
+one = "You have {{.Count}} unread email."
+other = "You have {{.Count}} unread emails."
+
+[person_unread_email_count]
+one = "{{.Person}} has {{.Count}} unread email."
+other = "{{.Person}} has {{.Count}} unread emails."
+
+[person_unread_email_count_timeframe]
+one = "{{.Person}} has {{.Count}} unread email in the past {{.Timeframe}}."
+other = "{{.Person}} has {{.Count}} unread emails in the past {{.Timeframe}}."
+
+[d_days]
+one = "{{.Count}} day"
+other = "{{.Count}} days"
diff --git a/goi18n/testdata/input/flat/ar-ar.one.json b/goi18n/testdata/input/flat/ar-ar.one.json
deleted file mode 100644
index 6ae8d01..0000000
--- a/goi18n/testdata/input/flat/ar-ar.one.json
+++ /dev/null
@@ -1,45 +0,0 @@
-{
-  "d_days": {
-    "few": "arabic few translation of d_days",
-    "many": "arabic many translation of d_days",
-    "one": "",
-    "other": "",
-    "two": "",
-    "zero": ""
-  },
-
-  "person_greeting": {
-    "other": "arabic translation of person_greeting"
-  },
-
-  "person_unread_email_count": {
-    "few": "arabic few translation of person_unread_email_count",
-    "many": "arabic many translation of person_unread_email_count",
-    "one": "arabic one translation of person_unread_email_count",
-    "other": "",
-    "two": "",
-    "zero": ""
-  },
-
-  "person_unread_email_count_timeframe": {
-    "few": "",
-    "many": "",
-    "one": "",
-    "other": "",
-    "two": "",
-    "zero": ""
-  },
-
-  "program_greeting": {
-    "other": ""
-  },
-
-  "your_unread_email_count": {
-    "few": "",
-    "many": "",
-    "one": "",
-    "other": "",
-    "two": "",
-    "zero": ""
-  }
-}
diff --git a/goi18n/testdata/input/flat/ar-ar.one.toml b/goi18n/testdata/input/flat/ar-ar.one.toml
new file mode 100644
index 0000000..364a62c
--- /dev/null
+++ b/goi18n/testdata/input/flat/ar-ar.one.toml
@@ -0,0 +1,37 @@
+[d_days]
+few = "arabic few translation of d_days"
+many = "arabic many translation of d_days"
+one = ""
+other = ""
+two = ""
+zero = ""
+
+[person_greeting]
+other = "arabic translation of person_greeting"
+
+[person_unread_email_count]
+few = "arabic few translation of person_unread_email_count"
+many = "arabic many translation of person_unread_email_count"
+one = "arabic one translation of person_unread_email_count"
+other = ""
+two = ""
+zero = ""
+
+[person_unread_email_count_timeframe]
+few = ""
+many = ""
+one = ""
+other = ""
+two = ""
+zero = ""
+
+[program_greeting]
+other = ""
+
+[your_unread_email_count]
+few = ""
+many = ""
+one = ""
+other = ""
+two = ""
+zero = ""
diff --git a/goi18n/testdata/input/flat/en-us.one.json b/goi18n/testdata/input/flat/en-us.one.json
deleted file mode 100644
index 0d93a89..0000000
--- a/goi18n/testdata/input/flat/en-us.one.json
+++ /dev/null
@@ -1,23 +0,0 @@
-{
-  "program_greeting": {
-    "other": "Hello world"
-  },
-
-  "your_unread_email_count": {
-    "one": "You have {{.Count}} unread email.",
-    "other": "You have {{.Count}} unread emails."
-  },
-
-  "my_height_in_meters": {
-    "one": "I am {{.Count}} meter tall.",
-    "other": "I am {{.Count}} meters tall."
-  },
-
-  "person_unread_email_count_timeframe": {
-    "other": "{{.Person}} has {{.Count}} unread email in the past {{.Timeframe}}."
-  },
-
-  "d_days": {
-      "other": "this should get overwritten"
-  }
-}
diff --git a/goi18n/testdata/input/flat/en-us.one.yaml b/goi18n/testdata/input/flat/en-us.one.yaml
new file mode 100644
index 0000000..02ae001
--- /dev/null
+++ b/goi18n/testdata/input/flat/en-us.one.yaml
@@ -0,0 +1,16 @@
+program_greeting:
+  other: "Hello world"
+
+your_unread_email_count:
+  one: "You have {{.Count}} unread email."
+  other: "You have {{.Count}} unread emails."
+
+my_height_in_meters:
+  one: "I am {{.Count}} meter tall."
+  other: "I am {{.Count}} meters tall."
+
+person_unread_email_count_timeframe:
+  other: "{{.Person}} has {{.Count}} unread email in the past {{.Timeframe}}."
+
+d_days:
+  other: "this should get overwritten"
diff --git a/i18n/bundle/bundle.go b/i18n/bundle/bundle.go
index e3bc744..2ad1d7c 100644
--- a/i18n/bundle/bundle.go
+++ b/i18n/bundle/bundle.go
@@ -2,6 +2,7 @@
 package bundle
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
@@ -11,6 +12,7 @@ import (
 
 	"github.com/nicksnyder/go-i18n/i18n/language"
 	"github.com/nicksnyder/go-i18n/i18n/translation"
+	toml "github.com/pelletier/go-toml"
 	"gopkg.in/yaml.v2"
 )
 
@@ -78,12 +80,29 @@ func (b *Bundle) ParseTranslationFileBytes(filename string, buf []byte) error {
 }
 
 func parseTranslations(filename string, buf []byte) ([]translation.Translation, error) {
-	if buf == nil || len(buf) == 0 {
+	if len(buf) == 0 {
 		return []translation.Translation{}, nil
 	}
 
 	ext := filepath.Ext(filename)
 
+	// `github.com/pelletier/go-toml` has an Unmarshal function,
+	// that can't unmarshal to maps, so we should parse TOML format separately.
+	if ext == ".toml" {
+		tree, err := toml.LoadReader(bytes.NewReader(buf))
+		if err != nil {
+			return nil, err
+		}
+
+		m := make(map[string]map[string]interface{})
+		for k, v := range tree.ToMap() {
+			m[k] = v.(map[string]interface{})
+		}
+
+		return parseFlatFormat(m)
+	}
+
+	// Then parse other formats.
 	if isStandardFormat(ext, buf) {
 		var standardFormat []map[string]interface{}
 		if err := unmarshal(ext, buf, &standardFormat); err != nil {
@@ -115,9 +134,9 @@ func unmarshal(ext string, buf []byte, out interface{}) error {
 		return json.Unmarshal(buf, out)
 	case ".yaml":
 		return yaml.Unmarshal(buf, out)
-	default:
-		return fmt.Errorf("unsupported file extension %v", ext)
 	}
+
+	return fmt.Errorf("unsupported file extension %v", ext)
 }
 
 func parseStandardFormat(data []map[string]interface{}) ([]translation.Translation, error) {
diff --git a/i18n/translations_test.go b/i18n/translations_test.go
index 70c369b..86c5808 100644
--- a/i18n/translations_test.go
+++ b/i18n/translations_test.go
@@ -83,3 +83,7 @@ func TestJSONFlatParse(t *testing.T) {
 func TestYAMLFlatParse(t *testing.T) {
 	testFile(t, "../goi18n/testdata/en-us.flat.yaml")
 }
+
+func TestTOMLFlatParse(t *testing.T) {
+	testFile(t, "../goi18n/testdata/en-us.flat.toml")
+}