Replace T type with a truly generic one in the "How to Gracefully Close Channels" article

[GCrispino]

Hello everybody!

Now that we have generics, I believe we could leverage them in code examples like the below, in the "How to Gracefully Close Channels" article:

package main

import "fmt"

type T int

func IsClosed(ch <-chan T) bool {
	select {
	case <-ch:
		return true
	default:
	}

	return false
}

func main() {
	c := make(chan T)
	fmt.Println(IsClosed(c)) // false
	close(c)
	fmt.Println(IsClosed(c)) // true
}

This could be rewritten to:

package main

import "fmt"

func IsClosed[T any](ch <-chan T) bool {
	select {
	case <-ch:
		return true
	default:
	}

	return false
}

func main() {
	c := make(chan struct{})
	fmt.Println(IsClosed(c)) // false
	close(c)
	fmt.Println(IsClosed(c)) // true
}

---

Another example would be the following code sample in the same article:

func SafeClose(ch chan T) (justClosed bool) {
	defer func() {
		if recover() != nil {
			// The return result can be altered
			// in a defer function call.
			justClosed = false
		}
	}()

	// assume ch != nil here.
	close(ch)   // panic if ch is closed
	return true // <=> justClosed = true; return
}

That could be rewritten to:

func SafeClose[T any](ch chan T) (justClosed bool) {
	defer func() {
		if recover() != nil {
			// The return result can be altered
			// in a defer function call.
			justClosed = false
		}
	}()

	// assume ch != nil here.
	close(ch)   // panic if ch is closed
	return true // <=> justClosed = true; return
}

This is just an idea, I can see points being made to either accept it or not, so I'm just leaving it here in case you find it useful 🙂

[go101]

@GCrispino
Thanks for the suggestion. I think it is good and would be perfect when Go custom generics are used more popularly later.
At the moment, I don't want the generic thing distract reader's attentions.

So, let's hold the suggestion now.

[GCrispino]

@go101 Sure! Thanks for answering. Feel free to close the issue if you'd like