Sorry, just thought it could also use clear to start getting accostumed :)
<code>
// GroupValue returns a new Value for a list of Attrs.
// The caller must not subsequently mutate the argument slice.
func GroupValue(as ...Attr) Value {
// Remove empty groups.
// It is simpler overall to do this at construction than
// to check each Group recursively for emptiness.
var write int
for read := range as {
if !as[read].isEmptyGroup() {
if read != write {
as[write] = as[read]
}
write++
}
}
clear(as[write:]) // no need to keep a reference to the string Key
as = as[:write]
return Value{num: uint64(len(as)), any: groupptr(unsage.SliceData(as))}
}
</code>
On Monday, 14 August 2023 at 22:06:57 UTC-3 Diego Augusto Molina wrote:
> Hello everyone, thank you for reading. I'm looking at the code of
> slog.GroupValue (
> https://cs.opensource.google/go/go/+/refs/tags/go1.21.0:src/log/slog/value.go;l=171)
>
> and was wondering if we could benefit from reusing the same slice like this:
>
> <code>
> // GroupValue returns a new Value for a list of Attrs.
> // The caller must not subsequently mutate the argument slice.
> func GroupValue(as ...Attr) Value {
> // Remove empty groups.
> // It is simpler overall to do this at construction than
> // to check each Group recursively for emptiness.
> var write int
> for read := range as {
> if as[read].isEmptyGroup() {
> as[read] = Attr{} // no need to keep a reference to the
> string Key
> } else {
> if read != write {
> as[write] = as[read]
> }
> write++
> }
> }
> as = as[:write]
> return Value{num: uint64(len(as)), any: groupptr(unsage.SliceData(as))}
> }
> </code>
>
> This, considering that the documentation of the func already states that
> the user must not mutate the argument slice, so not only the elements but
> the whole slice could be reused.
> In the case of having lots of attributes with empty group elements, then
> the stored slice will be unnecessarily larger by that number of Attr
> elements, but I wonder if that would be negligible, probably an edge case
> of misuse.
>
> Kind regards.
>
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