On Wednesday, 15 June 2022 at 17:30:31 UTC, JG wrote:
On Wednesday, 15 June 2022 at 13:52:24 UTC, Christian Köstlin
wrote:
the naive version would look like
```d
auto next(Range)(Range r) {
r.popFront;
return r.front;
}
```
But looking at a mature library e.g.
https://github.com/submada/btl/blob/9cc599fd8495215d346ccd62d6e9f1f7ac140937/source/btl/vector/package.d#L229 is looks like there should be tons of annotations/attributes on it.
Kind regards,
Christian
I not sure of your use case. But you need to check if the range
is empty before and after calling popFront (and decide what to
if it is). Also unless you want the original range passed in
mutated you should call save (assuming you have a forward
range) before calling your next or you need to modify next so
it calls save.
This is what I would write for next (which should only be called
after
checking if the range is empty).
It produces a range whose front points at the next element.
```d
auto next(Range)(Range r) {
auto ret = r.save;
ret.popFront;
return ret;
}
```
