Yes, that makes sense. Thank you.
The example I wrote was concocted. But I've seen others do it on their own
types too, which didn't make sense at all. Maybe they were just
copy-pasting similar code from elsewhere.
On Saturday, 14 September 2019 20:20:49 UTC+5:30, Ben Burwell wrote:
>
> On Sat Sep 14, 2019 at 1:43 AM Sathish VJ wrote:
> > I saw some code where there is a temporary type called *noMethod*
> created
> > before performing custom marshaling.
> >
> > What is the purpose of doing this?
> >
> > type T struct {
> > A int
> > C string
> > }
> >
> > func (t T) MarshalJSON() (text []byte, err error) {
> > type noMethod T
> > return json.Marshal(noMethod(t))
> > }
> >
> > https://play.golang.org/p/e8cZfkU1uvE
>
> When json.Marshal is called, if the value passed implements
> json.Marshaler, then that method is called to marshal the value.
>
> If you wrote
>
> func (t T) MarshalJSON() (text []byte, err error) {
> return json.Marshal(t)
> }
>
> func main() {
> var t T
> json.Marshal(t)
> }
>
> then you'd end up with infinite recursion, as the T.MarshalJSON() method
> would just keep getting called. By defining `type noMethod T` and
> casting t to a noMethod before calling json.Marshal, you can avoid this
> because the noMethod type has, well, no methods, and thus does not
> implement json.Marshaler and will be encoded using the struct encoder.
>
> In this case, you may as well just not implement json.Marshaler at all
> and fall through immediately to the struct encoder, but perhaps there's
> some reason to do this that your example doesn't show.
>
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