[ghc-steering-committee] #626: Amendment of Visible Forall in Types, recommendation: Accept

[Arnaud Spiwack]

Alright, no further opinions. I'll interpret, as is the custom, silence as
assent, and mark this proposal as accepted.

On Fri, 12 Jan 2024 at 11:12, Arnaud Spiwack <arnaud.spiwack at tweag.io>
wrote:

> I actually hadn't noticed, thanks Richard. For the record: said change
> removes the icky ambiguity on `p -> q`, which is always parsed as a view
> pattern.
>
>
> On Fri, 12 Jan 2024 at 02:22, Richard Eisenberg <rae at richarde.dev> wrote:
>
>> (For what it's worth, my suggestion was accepted and has been
>> incorporated into the proposal.)
>>
>> On Jan 9, 2024, at 10:43 AM, Arnaud Spiwack <arnaud.spiwack at tweag.io>
>> wrote:
>>
>> Any other thoughts? If not, I'll consider this proposal accepted at the
>> end of this week.
>>
>> On Tue, 2 Jan 2024 at 13:55, Richard Eisenberg <rae at richarde.dev> wrote:
>>
>>> I support the amendment. I made one small suggestion, but I wish to vote
>>> for acceptance regardless of the status of this suggestion.
>>>
>>> Richard
>>>
>>> On Dec 22, 2023, at 9:20 AM, Arnaud Spiwack <arnaud.spiwack at tweag.io>
>>> wrote:
>>>
>>> I realised today that we haven't completed the vote on this. This is
>>> really a very simple proposal, let's not spend too long on this. I'll be on
>>> holiday for the next two weeks, I'm a bit embarrassed to send this email
>>> only now. But please opine soon. I'd like to be able to give an answer soon
>>> after I'm back (say on the 12th January)
>>>
>>> Best,
>>> Arnaud
>>>
>>> On Mon, 11 Dec 2023 at 11:06, Simon Peyton Jones <
>>> simon.peytonjones at gmail.com> wrote:
>>>
>>>> I recommend acceptance too.  It's all very fine detail.
>>>>
>>>> The actual diff seems quite large but that's because I encouraged Vlad
>>>> to take the opportunity to clarity the rather cryptic sentence in the
>>>> original #218, namely "The syntactic descriptions here applying to
>>>> expressions apply equally to patterns, though we will continue to discuss
>>>> only expressions."  Instead it is all spelled out much more explicitly,
>>>> which is way better.  Indeed spelling it out showed up a dark corner to do
>>>> with view patterns, hence the icky stuff Arnaud mentions.
>>>>
>>>> Simon
>>>>
>>>>    -
>>>>
>>>>
>>>> On Mon, 11 Dec 2023 at 09:56, Arnaud Spiwack <arnaud.spiwack at tweag.io>
>>>> wrote:
>>>>
>>>>> Dear all,
>>>>>
>>>>> Vlad is proposing to amend his own proposal
>>>>> https://github.com/ghc-proposals/ghc-proposals/pull/626
>>>>>
>>>>> Being an amendment, it's, as always, not as straightforward to
>>>>> consume, but Vlad gives us a good summary of the changes in his
>>>>> pull-request description.
>>>>>
>>>>> All in all, it's almost entirely straightforward clarification. There
>>>>> are two items of notice: patterns for visible forall arguments were
>>>>> specified as: only variable or wildcard. The amendment changes it to allow
>>>>> data constructors applied to (0 or more) patterns as well. The amended
>>>>> version is consistent with how patterns for invisible forall arguments are
>>>>> specified. The second, and this one is for Moritz, is a small change in the
>>>>> parsing of view patterns (it does break two packages at least on Hackage,
>>>>> but I actually don't quite understand how the change can affect semantics.
>>>>> It's that tiny. Vlad proposes 3 releases with warning before effecting the
>>>>> change).
>>>>>
>>>>> Maybe there's a third item: `p -> q` parses differently depending on
>>>>> whether ViewPattern or RequiredTypeArguments (or both) is turned on. This
>>>>> is kind of icky, I suppose. But in the case where both are on, then
>>>>> ViewPattern wins, so there's no real harm in it.
>>>>>
>>>>> Do pay some attention to the new items in the alternatives section.
>>>>>
>>>>> Anyway, I recommend we accept.
>>>>>
>>>>> --
>>>>> Arnaud Spiwack
>>>>> Director, Research at https://moduscreate.com and https://tweag.io.
>>>>> _______________________________________________
>>>>> ghc-steering-committee mailing list
>>>>> ghc-steering-committee at haskell.org
>>>>>
>>>>> https://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-steering-committee
>>>>>
>>>>
>>>
>>> --
>>> Arnaud Spiwack
>>> Director, Research at https://moduscreate.com and https://tweag.io.
>>> _______________________________________________
>>> ghc-steering-committee mailing list
>>> ghc-steering-committee at haskell.org
>>> https://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-steering-committee
>>>
>>>
>>>
>>
>> --
>> Arnaud Spiwack
>> Director, Research at https://moduscreate.com and https://tweag.io.
>>
>>
>>
>
> --
> Arnaud Spiwack
> Director, Research at https://moduscreate.com and https://tweag.io.
>


-- 
Arnaud Spiwack
Director, Research at https://moduscreate.com and https://tweag.io.
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