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 <javascript:>> 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+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
