Anonymous field handling for NBT

nbt/interface.go

@@ -10,3 +10,16 @@ type Marshaler interface {
 	TagType() byte
 	MarshalNBT(w io.Writer) error
 }
+
+// FieldsUnmarshaler is a type can hold many Tags just like a TagCompound.
+//
+// If and only if a type which implements this interface is used as an anonymous field of a struct,
+// and didn't set a struct tag, the content it holds will be considered as in the outer struct.
+type FieldsUnmarshaler interface {
+	UnmarshalField(tagType byte, tagName string, r DecoderReader) (ok bool, err error)
+}
+
+// FieldsMarshaler is similar to FieldsUnmarshaler, but for marshaling.
+type FieldsMarshaler interface {
+	MarshalFields(w io.Writer) (ok bool, err error)
+}