New EEP draft: Pinning operator ^ in patterns

[Loïc Hoguin]

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 have to try to reassign a variable
> 
> no. i have to check if it is bound or not.
> i am sure this check is already happening somewhere.

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.

-- 
Loïc Hoguin
https://ninenines.eu