On Thursday, October 13, 2016 at 11:22:14 PM UTC+8, Chris Manghane wrote: > > In that example y is a nil interface value of type l. The last line > implies that for a type assertion to another interface type, the operation > will only be possible if the underlying value implements both interfaces. > That is, the value must have an m() method as well as all of io.reader > methods or the type assertion will like the above assertion to a string > type. >
It would be great if the spec can explain things as clear as you. > > On Oct 13, 2016 7:48 AM, <di...@veryhaha.com <javascript:>> wrote: > > > > On Thursday, October 13, 2016 at 8:52:14 PM UTC+8, Jan Mercl wrote: > >> On Thu, Oct 13, 2016 at 2:42 PM <di...@veryhaha.com> wrote: >> >> > I don't understand the comment of the last line. Can someone explain it >> for me? >> >> "r has type io.Reader" means that the type if expr.(T) is T. >> >> "and y must implement both I and io.Reader" >> >> y is either nil or it implements I, because that's how it was declared >> and nothing not implementing I can be assigned to it. The dynamic type of y >> can implement any number of interfaces, so it can implement both I and >> io.Reader. The later is checked at run time when the type assertion >> expression y.(io.Reader) is actually evaluated. >> >> -- >> >> -j >> > > So "y must implement both I and io.Reader" means short form of "the > dynamic type of y must implement both I and io.Reader"? > My brain really can't accept this short form. > > And in that example, it gives people the impression y is nil. I really > think it is a bad example. > > > > > > > I feel that comment (and that example) is very not professional for these > reason: > 1. y is a value of type I, > > > -- > 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...@googlegroups.com <javascript:>. > For more options, visit https://groups.google.com/d/optout. > > > -- 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. For more options, visit https://groups.google.com/d/optout.
