Marshal hierarchical structs

marshal.go

@@ -10,12 +10,14 @@ type metakind uint
 
 const (
 	metakindBasic metakind = iota
+	metakindStruct
 	metakindUnsupported
 )
 
 func Marshal(input interface{}) ([]byte, error) {
 	i := reflect.ValueOf(input)
 
+	// TODO: use actualMetakind() or similar
 	if i.Kind() == reflect.Ptr {
 		i = i.Elem()
 	}
@@ -35,7 +37,7 @@ func Marshal(input interface{}) ([]byte, error) {
 func marshal(ctx context, in reflect.Value) (map[string]interface{}, error) {
 	out := make(map[string]interface{})
 
-	t := in.Type()
+	t := actualType(in)
 	for i := 0; i < t.NumField(); i++ {
 		v := in.Field(i)
 		f := t.Field(i)
@@ -44,6 +46,12 @@ func marshal(ctx context, in reflect.Value) (map[string]interface{}, error) {
 		switch actualMetakind(v) {
 		case metakindBasic:
 			out[f.Name] = v.Interface()
+		case metakindStruct:
+			r, err := marshal(ctx, actualValue(v))
+			if err != nil {
+				return nil, err
+			}
+			out[f.Name] = r
 		default:
 			return nil, NewUnsupportedTypeError(ctx, actualType(v))
 		}
@@ -56,6 +64,8 @@ func actualMetakind(v reflect.Value) metakind {
 	switch v.Kind() {
 	case reflect.Interface:
 		return actualMetakind(v.Elem())
+	case reflect.Struct:
+		return metakindStruct
 	case reflect.String, reflect.Bool,
 		reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
 		reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64,
@@ -74,3 +84,12 @@ func actualType(v reflect.Value) reflect.Type {
 		return v.Type()
 	}
 }
+
+func actualValue(v reflect.Value) reflect.Value {
+	switch v.Kind() {
+	case reflect.Interface:
+		return v.Elem()
+	default:
+		return v
+	}
+}

marshal_test.go

@@ -25,6 +25,7 @@ var _ = Describe("Marshal", func() {
 			Entry("boolean", c{V: true}, `{"V":true}`),
 			Entry("int", c{V: 42}, `{"V":42}`),
 			Entry("float", c{V: 4.2}, `{"V":4.2}`),
+			Entry("struct", c{V: c{V: "hierarchical"}}, `{"V":{"V":"hierarchical"}}`),
 		)
 
 		DescribeTable(