Can't range over iter.Seq in text/template (go 1.22/dev)

[Rory Campbell-Lange]

I don't seem to be able to range over an iter.Seq in a template.

error: executing "test" at <.>: range can't iterate over 0x5103c0

resulter := func(yield func(int) bool) {
for _, v := range []int{1, 2, 3} {
if !yield(v) {
return
}
}
}

tpl := `{{ range $aa := . }}{{ $aa }} {{ end }}`

tplParsed := template.Must(template.New("test").Parse(tpl))
err := tplParsed.Execute(os.Stdout, resulter)
if err != nil {
fmt.Println(err)
}

https://go.dev/play/p/f1mrGFnfiUa?v=gotip

https://pkg.go.dev/text/template says:
{{range pipeline}} T1 {{end}}
The value of the pipeline must be an array, slice, map, or channel

...is an iter.Seq or iter.Seq2 not intended to be added there?

Thanks,
Rory

[Ian Lance Taylor]

On Sat, Jul 6, 2024 at 2:21 PM Rory Campbell-Lange
<ro...@campbell-lange.net> wrote:
>
> I don't seem to be able to range over an iter.Seq in a template.

...

> ...is an iter.Seq or iter.Seq2 not intended to be added there?

Yes, this is https://go.dev/issue/66107.

Ian

[Rory Campbell-Lange]

Apologies, I didn't spot that.