On Saturday, August 6, 2016 at 4:06:07 PM UTC+8, atd...@gmail.com wrote: > > Possibily, if you freeze the type of things that can be boxed by the > interface. But what would it be useful for ? > That would just mean that an interface is constant. Not even that the > value it wraps can't be changed (because with the current implementation, > the values an interface wraps need to be addressable). >
no, the value an interface wraps can't be addressed. const bool/number/string interfaces make it is possible the exported error variables in standard lib become constant. > > > > On Saturday, August 6, 2016 at 9:53:26 AM UTC+2, T L wrote: >> >> Is it possible to make an interface constant if its concrete value type >> is bool/number/string? >> >> On Saturday, August 6, 2016 at 3:48:17 AM UTC+8, Ian Lance Taylor wrote: >>> >>> On Fri, Aug 5, 2016 at 11:21 AM, T L <tapi...@gmail.com> wrote: >>> > >>> > For an interface value, its internal values will never change. >>> > Are there any problems if golang supports constant interface values? >>> >>> Pedantically, in Go, constants are untyped by default. It doesn't >>> make sense to speak of an untyped interface value. I would describe >>> what you are asking for as an immutable variable. I've often thought >>> that immutable variables would be useful in Go, but since they have to >>> be initialized it's not that simple. For example, io.EOF is >>> initialized using a function call. That means that it can't actually >>> be in read-only memory, and of course it's possible to take it's >>> address. How do we prevent it from being changed, without introducing >>> an immutable qualifier into the type system? It's a complex problem >>> for which I have no solution. And the benefits of an immutable >>> variable aren't all that high. >>> >>> Ian >>> >> -- 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.
