Ugh. Every time I see that I cringe....

> On Oct 9, 2019, at 7:58 PM, burak serdar <bser...@computer.org> wrote:
> 
> ´╗┐On Wed, Oct 9, 2019 at 5:48 PM 'Axel Wagner' via golang-nuts
> <golang-nuts@googlegroups.com> wrote:
>> 
>> There's loads of precedence in the stdlib:
>> 
>> https://godoc.org/net/http/#FileSystem.Open
>> https://godoc.org/net/http#File.Stat
>> https://godoc.org/net#Conn.LocalAddr
>> https://godoc.org/database/sql/driver/#Driver.Open
>> https://godoc.org/image#Image.ColorModel
>> https://godoc.org/reflect/#Type.Elem
>> And don't forget that error itself is an interface.
>> 
>> Honestly, if you need it, go for it. There are definitely places where it's 
>> over abstraction to do it, but I don't think there's a good or universal 
>> rule you can use to decide which is which.
>> 
>> FWIW, I tend to disagree with the "return structs, accept interfaces" advise 
>> in general. If go had variant func/methods, that would be useful guidance. 
>> But as it stands, it is too often necessary to violate it (every usage of an 
>> error return value is in fact such a violation). And the "accept interfaces" 
>> part tends to lead to over abstraction (I would probably agree with 
>> "consider accepting interfaces if they already exist" though).
> 
> 
> There is one point you need to remember when returning interfaces:
> make sure you handle nil correctly:
> 
> type S struct {}
> 
> type I interface {}
> 
> func f() *S {
>  return nil
> }
> 
> func g() I {
>  x:=f()
>  return x
> }
> 
> Above, g() is not nil. The correct code would be:
> 
> func g(() I {
>  x:=f()
>  if x==nil {
>   return nil
>  }
>  return x
> 
> }
> 
> 
>> 
>>> On Wed, Oct 9, 2019 at 9:39 AM Martin Palma <m...@palma.bz> wrote:
>>> 
>>> I'm wondering If it is ok (or good Go code) if an interface method returns 
>>> an other interface? Here an example:
>>> 
>>> type Querier interface {
>>> Query() string
>>> }
>>> 
>>> type Decoder interface {
>>> DecodeAndValidate() Querier
>>> }
>>> 
>>> 
>>> --
>>> You received this message because you are subscribed to the Google Groups 
>>> "golang-nuts" group.
>>> To unsubscribe from this group and stop receiving emails from it, send an 
>>> email to golang-nuts+unsubscr...@googlegroups.com.
>>> To view this discussion on the web visit 
>>> https://groups.google.com/d/msgid/golang-nuts/531f29a6-ea2e-4416-a0d0-ce697dc7a09b%40googlegroups.com.
>> 
>> --
>> You received this message because you are subscribed to the Google Groups 
>> "golang-nuts" group.
>> To unsubscribe from this group and stop receiving emails from it, send an 
>> email to golang-nuts+unsubscr...@googlegroups.com.
>> To view this discussion on the web visit 
>> https://groups.google.com/d/msgid/golang-nuts/CAEkBMfHHtn5t3TZOCG4xA_3kVbNqY2_xo7EtHoLyhi6P28ku9g%40mail.gmail.com.
> 
> -- 
> You received this message because you are subscribed to the Google Groups 
> "golang-nuts" group.
> To unsubscribe from this group and stop receiving emails from it, send an 
> email to golang-nuts+unsubscr...@googlegroups.com.
> To view this discussion on the web visit 
> https://groups.google.com/d/msgid/golang-nuts/CAMV2Rqp-n0UaxQVpPVgJKayNzY6Voe5QRL4n7MoqmQMavL3oiQ%40mail.gmail.com.

-- 
You received this message because you are subscribed to the Google Groups 
"golang-nuts" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to golang-nuts+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/golang-nuts/FF0701C3-2FEB-4BD7-BD60-EB39CDE7E6E2%40ix.netcom.com.

Reply via email to