On Saturday, August 31, 2019 at 4:04:29 AM UTC-4, T L wrote: > > > > On Saturday, August 31, 2019 at 2:32:26 AM UTC-4, rog wrote: >> >> The reason you're wanting priority select is because you are shutting >> down the data channel preemptively, but you can wait for an acknowledgement >> from the run goroutine instead: >> >> https://play.golang.org/p/qSWluYy4ifl >> >> > Your solution is clever. The Close method can be called multiple time > safely. > Is there such a beautiful solution for multiple senders? > >
Translating a multi-senders problem to a single sender problem is the only way I can get: https://play.golang.org/p/dAppUxP96g4 > >> On Wed, 28 Aug 2019 at 18:06, T L <tapi...@gmail.com> wrote: >> >>> The old thread: >>> https://groups.google.com/forum/#!topic/golang-nuts/ZrVIhHCrR9o >>> >>> Go channels are flexible, but in practice, I often encountered some >>> situations in which channel are hard to use. >>> Given an example: >>> >>> import "math/rand" >>> >>> type Producer struct { >>> data chan int >>> closed chan struct{} >>> } >>> >>> func NewProducer() *Producer { >>> p := &Producer { >>> data: make(chan int), >>> closed: make(chan struct{}), >>> } >>> >>> go p.run() >>> >>> return p >>> } >>> >>> func (p *Produce) Stream() chan int { >>> return p.data >>> } >>> >>> func (p *Producer) run() { >>> for { >>> // If non-blocking cases are selected by their appearance order, >>> // then the following slect block is a perfect use. >>> select { >>> case(0) <-p.closed: return >>> case p.data <- rand.Int(): >>> } >>> } >>> } >>> >>> func (p *Produce) Clsoe() { >>> close(p.closed) >>> close(p.data) >>> } >>> >>> func main() { >>> p := NewProducer() >>> for n := p.Stream() { >>> // use n ... >>> } >>> } >>> >>> >>> If the first case in the select block in the above example has a higher >>> priority than the second one, >>> then coding will be much happier for the use cases like the above one. >>> >>> In short, the above use case requires: >>> * for receivers, data streaming end is notified by the close of a >>> channel. >>> * for senders, data will never be sent to closed channel. >>> >>> But, as Go 1 doesn't support priority select cases, it is much tedious >>> to implement the code >>> satisfying the above listed requirements. The final implementation is >>> often very ugly and inefficient. >>> >>> Does anyone else also experience the pain? >>> >>> -- >>> 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 golan...@googlegroups.com. >>> To view this discussion on the web visit >>> https://groups.google.com/d/msgid/golang-nuts/e3015cd8-c2ec-479e-927d-b9ad762d277e%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/golang-nuts/e3015cd8-c2ec-479e-927d-b9ad762d277e%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/e239c78f-61fc-4238-aa5d-f776cb9aec03%40googlegroups.com.
