New EEP draft: Pinning operator ^ in patterns

[Eugene]

On 1/22/21 5:27 PM, Raimo Niskanen wrote:
> On Fri, Jan 22, 2021 at 01:22:02PM +0100, Eugene wrote:
>> On 1/22/21 9:25 AM, Richard Carlsson wrote:
>>> In many normal cases, the ^-annotation can look superfluous.
>>
>> show me an example where annotating an *UNbound* var
>> is not useful.
> 
> foo() ->
>      ^A = 2,
>      A.
> 
> If that is what you ment; annotating every time a new variable is bound
> is not practical, because binding is much more common than using
> a variable in pattern matching.

using a variable in general is much more common than binding,
and it is easier to read a plain mention "Variable"
regardless of context.

you can omit "^"
if you consider a match too obvious.

however!

you example shows us that the ENTIRETY OF THE SCOPE
is required to make it known that "A" was not bound earlier.