It is a known and documented behaviour. Even though it could be surprising
for some, we would need a very strong reason to remove it from the
language, and I don't think we have one here.



*José Valim*
www.plataformatec.com.br
Skype: jv.ptec
Founder and Director of R&D

On Sun, Dec 25, 2016 at 11:28 AM, miwee <[email protected]> wrote:

> TLDR: it's a nit picking and may introduce breaking changes without
> possibly any significant gain, except conceptual clarity and explicitness.
>
> iex(27)> n = 4
> 4
> iex(28)> 1..n |> Enum.into([])
> [1, 2, 3, 4]
> iex(29)> n = 1
> 1
> iex(30)> 1..n |> Enum.into([])
> [1]
> iex(31)> n = 0
> 0
> iex(32)> 1..n |> Enum.into([])
> [1, 0]
>
> The result for n = 0, is little bit magical, as I was expecting it to
> return [], but instead it auto-magically detected that end is less than
> start and hence it counted decrementally. I think it creates confusion,
> particularly when both start and end are not constants like the above case
> given.
>
> So does it make sense to restrict the behavior of .. operator to always
> count incrementally. For the case of decremental counting Enum.reverse can
> be used. In that sense 1..4 |> Enum.reverse() is identical to present
> behaviour of 4..1
>
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