Re:Go is boring, and that’s fantastic
by masklinn on Sunday July 05, 2020 @04:52AM
(#23737426)
> I do understand that. I'm not so sure it's so important
It absolutely is, even more so because of Go's interface. The difficulty of properly discriminating between interfaces extending one another is a reason the FAQ gives for rejecting union types.
> compared to Just being able to say that a box can contain either A or B or C.
I'd argue that this is by far the lesser use case, and furthermore trivially and completely subsumed by the alternative.
> Sometimes though you need to carry around one out of N types of something and currently all you can do is to use an interface{} and deal with the possibility of a runtime error if somebody breaks the invariant.
And sometimes you need to carry around one of N values some of which have overlapping contents and currently all you can do is get bent.
It absolutely is, even more so because of Go's interface. The difficulty of properly discriminating between interfaces extending one another is a reason the FAQ gives for rejecting union types.
> compared to Just being able to say that a box can contain either A or B or C.
I'd argue that this is by far the lesser use case, and furthermore trivially and completely subsumed by the alternative.
> Sometimes though you need to carry around one out of N types of something and currently all you can do is to use an interface{} and deal with the possibility of a runtime error if somebody breaks the invariant.
And sometimes you need to carry around one of N values some of which have overlapping contents and currently all you can do is get bent.