tlb support Unmarshal a cell to a message struct and opCode

[studyzy]

Currently, tlb only have:
func Unmarshal(c *boc.Cell, o any) error
but when the Cell is a message with OpCode, I must define a struct with OpCode uint32.

What I want?

I want to have a new function:

func UnmarshalMessage(c *boc.Cell, o any) (opCode uint32, err error)

So I don't need define new message struct with OpCode.

[studyzy]

For example,

Old code

type TokenExcesses struct {
	QueryId uint64
}
type TokenExcessesWithOpCode struct {
	OpCode  uint32
	QueryId uint64
}
func parseTokenExcesses(rawBody string) (*TokenExcesses, error) {
	cells, err := boc.DeserializeBocHex(rawBody)
	if err != nil {
		return nil, err
	}
	//define new struct with opCode
	ex := TokenExcessesWithOpCode{}
	err = Unmarshal(cells[0], &ex)
	if err != nil {
		return nil, err
	}
	//return struct without opCode
	return &TokenExcesses{QueryId: ex.QueryId}, nil
}
func Test_Unmarshal(t *testing.T) {
	rawBody := "b5ee9c7201010101000e000018d53276db546de4efe9d175f0"
	ex, err := parseTokenExcesses(rawBody)
	assert.NoError(t, err)
	t.Logf("%+v", ex)
}

New code

type TokenExcesses struct {
	QueryId uint64
}

func newParseTokenExcesses(rawBody string) (*TokenExcesses, error) {
	cells, err := boc.DeserializeBocHex(rawBody)
	if err != nil {
		return nil, err
	}
	ex := TokenExcesses{}
	opCode, err := UnmarshalMessage(cells[0], &ex)
	if err != nil {
		return nil, err
	}
	if opCode != uint32(0xd53276db) {
		return nil, fmt.Errorf("unexpected opCode: %x", opCode)
	}
	//return struct without opCode
	return &ex, nil
}