Re: [Caml-list] destructive local opens

[octachron <octa@polychoron.fr>]

Splitting 44 between alphanumeric and other identifiers is a nice 
default but it sounds a little arbitrary. Maybe it would make sense to 
combine this splitting with your [@shadow] annotation idea (cf. 
https://github.com/ocaml/ocaml/pull/218#issuecomment-123998749) ?

Like this, library writers could annotate identifiers that are intended 
to shadow predefined identifiers without any limitations, and cautious 
users could activate 53 to protect themselves from unexpected 
identifiers shadowing?

Regards,
octachron.

On 08/03/15 16:37, Gabriel Scherer wrote :
> We could split 44 in two warnings, one (52 ?) for alphanumeric
> identifiers and the other (53 ?) for symbol identifiers (infix and
> prefix operations, but also now the indexed read and write syntax),
> and enable 52 by default. The more paranoid people may then enable 53
> explicitly (and those that enable 44 explicitly today would retain the
> current behavior).
>
>
> On Mon, Aug 3, 2015 at 4:24 PM, Daniel Bünzli
> <daniel.buenzli@erratique.ch> wrote:
>> Le lundi, 3 août 2015 à 15:08, Nils Becker a écrit :
>>> It's possible that people actually want M.() to mean let open! more
>>> often than let open. For me I think that's the case.
>> If you are in the vector case, I don't think that's the case. With Gg [1] I often had the following kind of subtly wrong code (can't remember the exact details but something similar):
>>
>> let ox = V2.((dot v ox) * ox) in
>> V2.(3 * ox + oy)
>>
>> The reality is that M.() is inherently dangerous, especially from an API evolution perspective where new identifiers with matching type may get introduced later leading to silent semantic changes in your code. So we should not encourage people to use M.!() as it's going to make the problem even more acute. Besides we should have that 44 warning by default so that we see the problems, but for now it's impossible to live with 44 and a Gg like library.
>>
>> Best,
>>
>> Daniel
>>
>> [1] http://erratique.ch/software/gg
>>
>>
>>
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