MarshalYAML interface for struct and pointer both

[cloudzhou]

code:

type wrapint struct {
	i int
}
func (w *wrapint) MarshalYAML() (interface{}, error) {
	return w.i, nil
}

run yaml.Marshal() for
1) w := wrapint{i: 10} it will output "{}"
2) w := &wrapint{i: 10} it will output "10"

i think if it is necessary to output as "10" for both.

and if you make MarshalYAML to struct:

func (w wrapint) MarshalYAML() (interface{}, error) {
	return w.i, nil
}

both will output "10"

but for UnmarshalYAML，you sure need pointer as receiver in order to modify the value

[aathan]

#979