Just to be clear, are you aware of the sync/atomic package?
https://pkg.go.dev/sync/atomic
There are also some changes in there for Go 1.18, specifically the addition
of some types, so that only atomic operations can be done:
https://pkg.go.dev/sync/atomic@master
I mention this because atomic.Value and atomic.Pointer[T] are essentially
what you are suggesting here.
On Mon, May 23, 2022 at 8:04 AM Zhaoxun Yan <yan.zhao...@gmail.com> wrote:
> However, as I want to narrow the scope of this type down to generate
> integer types (as in the commented code), it encountered two obstacles:
>
> 1) It is not legal to embed a generic inside a struct, nor can it make
> generalized computation =+1
>
> 2) Inheritance is not available in golang, so type "Counter" cannot
> inherit type "Global" and get its methods automatically. I need to repeat
> Save and Load methods to "Counter".
>
> Am I correct? Or can you improve it?
>
You are correct that there is no way in Go to write a type which gets all
methods from an embedded field using generics. However, that is a good
thing. For example, say you could write
type Locked[T any] struct {
sync.Mutex
T
}
And this would get the methods of T and the methods of sync.Mutex. Then a
user could do
type Counter int64
func (c *Counter) Increment() { *c += 1 }
func main() {
var c Locked[Counter]
go c.Increment()
go c.Increment()
}
And get a data race. That is, a method can modify a value in a way that is
incompatible with what your wrapper type is trying to do.
That's really the crux of both of the obstacles you mention. You can't run
arbitrary computations and you can't promote methods, because *not all
computation and not all methods can be made concurrency safe this way*.
It's best to be intentional about it and explicitly acquire and release a
mutex around the critical sections of your code - because ultimately, only
your code knows which sections are critical.
>
--
> 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/baa74bff-6688-4d39-843b-c99a4fea2d1an%40googlegroups.com
> <https://groups.google.com/d/msgid/golang-nuts/baa74bff-6688-4d39-843b-c99a4fea2d1an%40googlegroups.com?utm_medium=email&utm_source=footer>
> .
>
--
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/CAEkBMfHL0-rd%3DPJ04_Qhk9WnHKA5xza8FzpqzFi%2BPPTxFb%2BL1g%40mail.gmail.com.
