On Saturday, October 26, 2019 at 9:47:39 PM UTC+2, Ian Lance Taylor wrote: > > On Sat, Oct 26, 2019 at 10:50 AM atd...@gmail.com <atd...@gmail.com > <javascript:>> wrote: > > > > I get that we can do that but it's not strictly about slices operations > such as appending or copying. > > Of course, we could copy slices all the time but then there is no > benefit in having them and it is not ergonomic as your example shows, nor > does it fit your performance cost requirements. > > > > If you look at the code snippet I posted, I am merely assigning a value > of type slice to a struct field. Now, that struct can be copied a number of > times without its actual value changing. It looks immutable in some sense. > BUT, it's actually implicitly tied to an object that is mutable (backing > array) and nowhere have we made sure that the mutation of this backing > array is safe. > > For better or for worse, the Go language has shared state. This is > most obvious when using pointers: if you copy a pointer, you do not > copy the memory to which that pointer points. If that is clear, then > the thing to remember about slices is that they are pointers. > Pointers in Go do not permit arithmetic.
> Slices in Go are pointers > that permit bounded arithmetic. > > Oh, I hadn't thought about it that way! Interesting. I still feel like there should be a way to reign in the amount of shared state in the cases of these "fat" pointers a little bit. Or at least, inspect it, warn about it more bceause most people seem to think that slices are just infinite arrays (hence the need for the extra-level of indirection/pointer). But perhaps, the coding patterns/idioms make it a non issue. For future considerations I guess. > 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. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/be142bd1-cbfc-4652-9381-c05f19f5ce81%40googlegroups.com.
