spec: document range-over-func

[rsc]

Tracking bug for adding range-over-func to spec. See #61405.

[gopherbot]

Change https://go.dev/cl/589397 mentions this issue: spec: document for range loop over functions

[3052]

@griesemer this example is not great

// print hello world
f := func(yield func(string) bool) {
	if yield("hello") {
		yield("world")
	}
}
for word := range f {
	println(word)
}

its not clear when yield would return true or false, looking at the example alone

[griesemer]

@3052 Agreed. And there's a TODO (html comment) in the spec to fix it. One step at a time.

[3052]

one of the reasons I love Go is that it is very "readable", but the above example is not that at all. I will be patient and wait on updates to the example, but I have strong concerns about the impact of this new change on how easy it is to read Go code.

[Malix-Labs]

@griesemer #65237 (comment)

there's a TODO (html comment) in the spec to fix it

Is there an opened issue about it ?

[griesemer]

Change is in the works.

[gopherbot]

Change https://go.dev/cl/590396 mentions this issue: spec: better examples for range-over-func