🏷️ Created Lang domain

go.mod

@@ -2,4 +2,7 @@ module source.toby3d.me/toby3d/jf2
 
 go 1.21.4
 
-require golang.org/x/net v0.18.0 // indirect
+require (
+	golang.org/x/net v0.18.0
+	golang.org/x/text v0.14.0
+)

go.sum

@@ -1,2 +1,4 @@
 golang.org/x/net v0.18.0 h1:mIYleuAkSbHh0tCv7RvjL3F6ZVbLjq4+R7zbOn3Kokg=
 golang.org/x/net v0.18.0/go.mod h1:/czyP5RqHAH4odGYxBJ1qz0+CE5WZ+2j1YgoEo8F2jQ=
+golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
+golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=

lang.go

@@ -0,0 +1,47 @@
+package jf2
+
+import (
+	"fmt"
+	"strconv"
+
+	"golang.org/x/text/language"
+)
+
+// Lang is the localization language of the containing object and all
+// sub-objects, unless overridden by another lang definition. Setting lang at a
+// lower level overrides any lang value set at higher levels.
+type Lang struct {
+	language.Tag
+}
+
+func (l *Lang) UnmarshalJSON(v []byte) error {
+	unquoted, err := strconv.Unquote(string(v))
+	if err != nil {
+		return fmt.Errorf("JF2: Lang: cannot unquote value: %w", err)
+	}
+
+	parsed, err := language.Parse(unquoted)
+	if err != nil {
+		return fmt.Errorf("JF2: Lang: cannot parse value as language tag: %w", err)
+	}
+
+	l.Tag = parsed
+
+	return nil
+}
+
+func (l Lang) MarshalJSON() ([]byte, error) {
+	if l.Tag != language.Und {
+		return []byte(strconv.Quote(l.Tag.String())), nil
+	}
+
+	return nil, nil
+}
+
+func (l Lang) String() string {
+	return l.Tag.String()
+}
+
+func (l Lang) GoString() string {
+	return "jf2.Lang(" + l.String() + ")"
+}

lang_test.go

@@ -0,0 +1,44 @@
+package jf2_test
+
+import (
+	"encoding/json"
+	"testing"
+
+	"golang.org/x/text/language"
+
+	"source.toby3d.me/toby3d/jf2"
+)
+
+func TestLang_UnmarshalJSON(t *testing.T) {
+	t.Parallel()
+
+	v := new(struct {
+		Lang jf2.Lang `json:"lang"`
+	})
+	if err := json.Unmarshal([]byte(`{"lang":"en-US"}`), v); err != nil {
+		t.Fatal(err)
+	}
+
+	expect := language.AmericanEnglish
+	if v.Lang.Tag != expect {
+		t.Errorf("got '%s', want '%s'", v.Lang.Tag, expect)
+	}
+}
+
+func TestLang_MarshalJSON(t *testing.T) {
+	t.Parallel()
+
+	body, err := json.Marshal(struct {
+		Lang jf2.Lang `json:"lang"`
+	}{
+		Lang: jf2.Lang{Tag: language.AmericanEnglish},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	const expect string = `{"lang":"en-US"}`
+	if actual := string(body); actual != expect {
+		t.Errorf("got '%s', want '%s'", actual, expect)
+	}
+}