[go-nuts] Can't figure out how to create an All() iter.Seq[T] method

['Mark' via golang-nuts]

I've been trying to learn how to create an `All() iter.Seq[T]` method for a 
simple set type (a map wrapper):

playground <https://go.dev/play/p/wtWvvTf33AF?v=gotip>

It won't work in the playground of course, but when I do:
`GOEXPERIMENT=rangefunc go run .`
using Go 1.22 I get this error:
```
cannot use func(yield func(int, T) bool) {…} (value of type func(yield 
func(int, T) bool)) as iter.Seq[T] value in return statement
```
Can someone help me get this right please?

```
package main

import (
"cmp"
"fmt"
"iter"
)

func main() {
s := New(5, 10, 15, 20, 35)
for v := range s.All() {
fmt.Println(v)
}
}

type Set[T cmp.Ordered] map[T]struct{}

func New[T cmp.Ordered](elements ...T) Set[T] {
set := make(Set[T], len(elements))
for _, element := range elements {
set[element] = struct{}{}
}
return set
}

func (me Set[T]) All() iter.Seq[T] {
return func(yield func(int, T) bool) { // ERROR
n := 0
for key := range me {
if !yield(n, key) {
return
}
n++
}
}
}
```

-- 
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/73161d74-12eb-4be0-9ea4-a35a25758e8en%40googlegroups.com.