New EEP draft: Pinning operator ^ in patterns

[Eugene]

On 1/15/21 3:01 PM, Loïc Hoguin wrote:
> On 15/01/2021 14:56, Eugene wrote:
>> On 1/15/21 2:48 PM, Loïc Hoguin wrote:
>>> On 15/01/2021 14:13, Eugene wrote:
>>>>> The absence of this operator might make this more obvious
>>>> how does explicit annotation make anything LESS obvious?
>>>
>>> The warning says "you can't do that", it doesn't tell you why.
>>
>> it is easy to change if you annotate UNbound variables.
>> say
>> "Already Bound"
>> it does tell you everything.
> 
> I'm not going to annotate 99.5% of variable matches.

you don't have to.
i will.


> You're not a newcomer. This part of my reply is about teaching newcomers 
> Erlang, or newcomers learning Erlang. Examples are important to learn, 
> and the badmatch that occurs when trying to reassign a variable is an 
> important one to see.

yes. it is not going anywhere!
everything you have you keep.

in addition if you demand a variable to be UNbound,
you will get "already bound" instead of "bad match"
which is way more specific!