New EEP draft: Pinning operator ^ in patterns

Stefan Reichör stefan@REDACTED
Mon Jan 18 11:53:02 CET 2021

Hallo Loïc,

I am a newcomer to Erlang. I am subscribed to this list since a few
days. I am really positively surprised how active the Erlang community is.

> On 18/01/2021 10:47, Raimo Niskanen wrote:
>> On Sat, Jan 16, 2021 at 02:32:21AM +0900, zxq9 wrote:
>>> On 2021/01/16 0:35, Raimo Niskanen wrote:
>>>> 1) Would the language be a better language with a mandatory pinning operator?
>>> At the cost of *adding* something arbitrarily hard to research[1] syntax
>> There, again!.
>> Someone sidetracked right off into "it is bad to add this feature".
> I do not understand what you are trying to say. In my mind, if someone thinks a feature is bad, then it doesn't make the
> language better for them, and even less so if it's mandatory.
> It would also be very difficult to objectively say it's an improvement or not, because measuring the benefits in this case is
> not trivial as I've previously stated. So you're only going to get subjective opinions.
> Personally I'm all for the optional warning (current version of the warning), I'm OK with the operator if it was added along
> with proper local scoping but would likely not use it outside of that scenario (in my projects), and as such I would be very
> unhappy if the operator was mandatory.
> Being able to write "A = 5, A = inc(4)." is what makes the Erlang language the best I've used in my opinion.

Could you please explain the semantics of this statement?
It is not obvious for me as a beginner.

Why is such a statement so useful for you?

> So for the "mandatory" part I would say the language would become worse. If optional, the language would become better but
> only if added along with local scoping (or with a clear plan leading to local scoping, doesn't have to be done all at once),
> otherwise it's not an improvement in my opinion.
> Cheers,


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