[ghc-steering-committee] #380 GHC2021: Voting starts

[Spiwack, Arnaud]

On Sun, Nov 29, 2020 at 12:40 PM Simon Marlow <marlowsd at gmail.com> wrote:

> On Wed, 25 Nov 2020 at 11:21, Spiwack, Arnaud <arnaud.spiwack at tweag.io>
> wrote:
>
>> PostfixOperators: maybe
>>
>
> I'd like to make a case for this extension, on the grounds that it's a
> complete no-brainer.
>
> The name "PostfixOperators" makes it sound a lot more scary than it
> actually is. In fact it's just a tiny generalisation to the definition of
> left sections. You could almost regard it as a typo in the Haskell report -
> if it had been noticed that this rule was unnecessarily restrictive, I'm
> fairly sure it would have been fixed at the time.
>
>
> https://downloads.haskell.org/ghc/latest/docs/html/users_guide/glasgow_exts.html#extension-PostfixOperators
>

It took me several readings to understand what this extension does, to be
honest. I agree now, I'll change my vote.

On Sun, Nov 29, 2020 at 9:14 PM Alejandro Serrano Mena <trupill at gmail.com>
wrote:

>
>
> El dom, 29 nov 2020 a las 12:12, Simon Marlow (<marlowsd at gmail.com>)
> escribió:
>
>> On Wed, 25 Nov 2020 at 11:21, Spiwack, Arnaud <arnaud.spiwack at tweag.io>
>> wrote:
>>
>>>
>>> ## OverloadedX
>>>
>>> These extensions can confuse type inference, yielding ambiguous type
>>> variables message. And as much as I like them, I don't think it's safe
>>> to include them yet. Not until we have a reasonable story for
>>> defaulting literals.
>>>
>>> OverloadedLabels: no
>>> OverloadedLists: no
>>> OverloadedStrings: no
>>>
>>
>> For what it's worth, I've been writing code with OverloadedStrings for
>> several years now and in my experience it rarely causes a problem, even for
>> beginners. The context almost always provides enough information to resolve
>> the ambiguity. (admittedly I'm slightly surprised by this too, but
>> experience has convinced me)
>>
>> I don't have much experience with OverloadedLists, but I'd be prepared to
>> believe that it's a similar story there too.
>>
>
> Adding to this, I think that both OverloadedStrings and OverloadedLists go
> very well with the idea of overloaded literals story that Haskell already
> has for numbers.
>

On principle, I very much agree. In fact I almost always turn both
OverloadedStrings and OverloadedList on. But it also almost always causes
some type errors when I turn them on (well, ambiguity errors). Therefore,
I'm a bit dubious at the idea of making them the default. Even though
Alejandro's point is undeniable.
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