Re: [ghc-steering-committee] Status

9 Mar 2021

      I agree with Arnaud. The connection to dependent types is pretty tangential, really: it's all about whether we have `sizeOf @Bool` or `sizeOf Bool`. If we had no intention of dependent types, I'd probably favor the former. But forward-compatibility with the design sketch for dependent types (https://gitlab.haskell.org/ghc/ghc/-/wikis/dependent-haskell) suggests using the latter. The problem is that the latter choice is more challenging to support, and indeed drives much of the complexity in the proposal.

So, we are a bit stuck: do we favor the design that's easier to specify and implement today? or do we favor the design that will mesh better tomorrow (assuming tomorrow has dependent types)? Our answer to #378 will inform this decision.

Richard
...
On Mar 9, 2021, at 3:02 AM, Spiwack, Arnaud  wrote:
Simon's suggestion sounds like the proper thing to do to me too.
The connection between #281 and dependent types is a little superficial, but it #281 mixes the type syntax and the term syntax a bit more (in fact, most of the details in the proposal are about that). The ability to mix types and terms some way or another is central to having more dependent typing. So there is, at the very least, a need for synchronization between the various corresponding proposals. Though, in fact, this visible forall thing is part of the dependent type package that Richard has been working towards. It does fit somewhat naturally in the big picture.
On Tue, Mar 9, 2021 at 6:58 AM Iavor Diatchki mailto:iavor.diatchki@gmail.com> wrote:
I will wait a few more days to see if anyone else expresses an opinion, otherwise I'll do as Simon suggests.
Could someone clarify what does #281 have to do with dependent types?   The example that was brought up, and I think is pretty reasonable, is `sizeOf` from the `Storbale` class:  I might want to write `sizeOf @Bool`.  Is the plan to require that dependent types are enabled to write stuff like that?
-Iavor
On Mon, Mar 8, 2021 at 8:35 PM Richard Eisenberg mailto:rae@richarde.dev> wrote:
I have now submitted #378 for a committee decision (though I will forgive Joachim if he missed the notification among the 200 comments on that thread). So perhaps we can tackle all of this together.
Richard
...
On Mar 8, 2021, at 8:54 AM, Simon Peyton Jones via ghc-steering-committee mailto:ghc-steering-committee@haskell.org> wrote:
I don't think this proposal is the right place to discuss dependent types, so I propose that we reject the proposal.  To ensure progress, I'll do so within a week, so please discuss before then, if you think otherwise.
I would suggest that rather than “reject” (which sounds like “we don’t want this, don’t resubmit it”), we push it back saying that we agree that it’d be better to settle #378 first.  So we we’ll mark it as “needs revision” not because we have anything specific to suggest, but so that it’s back in the author’s control.  He should feel free to re-submit (perhaps revised in some way, as he sees fit) once #378 is resolved.
Simon
From: Iavor Diatchki mailto:iavor.diatchki@gmail.com> 
Sent: 06 March 2021 16:51
To: Simon Peyton Jones mailto:simonpj@microsoft.com>
Cc: Joachim Breitner mailto:mail@joachim-breitner.de>; ghc-steering-committee mailto:ghc-steering-committee@haskell.org>
Subject: Re: [ghc-steering-committee] Status
Hello,
This is the author's response to my query:
So, the situation seems to be as follows:
if we want dependent types (as described on that Wiki page), I would like to resubmit
if we do not want them, I will retract the proposal and close it
I need to know the committee’s stance on dependent types to proceed here.
I don't think this proposal is the right place to discuss dependent types, so I propose that we reject the proposal.  To ensure progress, I'll do so within a week, so please discuss before then, if you think otherwise.
-Iavor
On Fri, Mar 5, 2021 at 5:02 PM Iavor Diatchki mailto:iavor.diatchki@gmail.com> wrote:
OK, I posted a note on the git-hub, asking @int-index what he wants to do.
In case anyone needs a refresher, this is the discussion we had when I submitted this to the committee back in November:
https://mail.haskell.org/pipermail/ghc-steering-committee/2020-November/0018... https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmail.haskell.org%2Fpipermail%2Fghc-steering-committee%2F2020-November%2F001859.html&data=04%7C01%7Csimonpj%40microsoft.com%7C0b9f9dd78f934d620c5e08d8e0c0012f%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637506462581487239%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=2inDHN90f7OQ9XIcd76l50Lwwp6axEUZVdea%2BoRFZzg%3D&reserved=0
another somewhat relevant discussion that followed was this:
https://mail.haskell.org/pipermail/ghc-steering-committee/2020-November/0018... https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fmail.haskell.org%2Fpipermail%2Fghc-steering-committee%2F2020-November%2F001865.html&data=04%7C01%7Csimonpj%40microsoft.com%7C0b9f9dd78f934d620c5e08d8e0c0012f%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637506462581497234%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=k4jiWTo11nNFH6zHyw7oYMFfyl0kxkQEsXKSueeC2Mk%3D&reserved=0
and here is a link to the proposal and the git-hub discussion:
https://github.com/ghc-proposals/ghc-proposals/pull/281 https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fghc-proposals%2Fghc-proposals%2Fpull%2F281&data=04%7C01%7Csimonpj%40microsoft.com%7C0b9f9dd78f934d620c5e08d8e0c0012f%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637506462581497234%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=X7tkk61XrEd9utRxcQjA3Eh3Wi3cDXuJdMae%2BBcx3gM%3D&reserved=0
-Iavor
On Fri, Mar 5, 2021 at 3:13 PM Simon Peyton Jones mailto:simonpj@microsoft.com> wrote:
This is about #281 visible dependent quantification.
Our role is to accept, reject, or push back to the author for revision.  We should do so in a timely way.
If I were the shepherd I’d be asking the author “Do you want to revise the proposal at all in the light of all the discussion, or do you want the committee to decide yay/nay based on the proposal as it is now?”
He might want to revise/discuss a bit.  But if he says “please decide on it as-is” then I think you should make a recommendation: accept or reject.  (I don’t think the discussion has led to any specific revisions that we want to see.)
I sense you would recommend reject.   That’s totally fine. Then the rest of us have to make up our minds.  We might end up with a more nuanced position like “we are not ready to accept this now, so if you want a decision now, it’d be no; but feel free to ask the same question again in six months time”.
If you don’t feel able to be the shepherd, that’s fine too: tell Joachim and he’ll finger someone else!
But, by hook or by crook, I do think we should do something, not just sit on it.  Tom’s nudge is helpful.
Simon
From: Iavor Diatchki mailto:iavor.diatchki@gmail.com> 
Sent: 05 March 2021 19:42
To: Simon Peyton Jones mailto:simonpj@microsoft.com>
Cc: Joachim Breitner mailto:mail@joachim-breitner.de>; ghc-steering-committee mailto:ghc-steering-committee@haskell.org>
Subject: Re: [ghc-steering-committee] Status
I am being nudged to do something with this proposal,  but I am not sure what...   Is the rest of the committee OK with moving it back "revisions required", and if so what revisions would we like?
I would be quite happy if someone else wanted to shephard this.  As I mentioned before, I don't have much interest in DH, so I have not followed the really long discussion related to that, and if and how it might relate to #281.
My recommendation for the moment would be:
* This seems like a useful feature independent of DH, so it would be nice to come up with a concise notation to use the feature on its own, without worrying about DH.
Please let me know what you think, as I am not sure what is the committee's stance on the proposal.
-Iavor
On Thu, Feb 18, 2021 at 1:54 PM Simon Peyton Jones mailto:simonpj@microsoft.com> wrote:
There has been a broad further discussion.
What we advertise is that, rather that leave a proposal “under committee review”, we will push it back to the author with an invitation to resubmit when the discussion has died down and they feel ready to submit a proposal, revised in the light of the discussion.  That’s different to reject… it means that there is an ongoing debate so it’s not a good time for the committee to make a decision.
Simon
From: ghc-steering-committee mailto:ghc-steering-committee-bounces@haskell.org> On Behalf Of Iavor Diatchki
Sent: 18 February 2021 16:47
To: Joachim Breitner mailto:mail@joachim-breitner.de>
Cc: ghc-steering-committee mailto:ghc-steering-committee@haskell.org>
Subject: Re: [ghc-steering-committee] Status
On #381 I think the idea of visible quantification makes sense every now and then, but I don't like the concrete details of the proposal: the magic lifting of terms to types seems quite complicated, and using `type` as an explicit herald doesn't look nice.  So I don't think it's the right design, and therefore I suggest we reject the proposal.
I am sure that others would disagree as apparently this is an essential part of dependent Haskell.   I have not followed the large discussion that Richard created, as I am not particularly interested in the design being proposed, so perhaps someone else should champion this.
Aslo, I am not sure if I am actually on the committee, as I thought my term had expired?  That might be more reason for someone else to pick it up.
-Iavor
On Thu, Feb 18, 2021 at 2:32 AM Joachim Breitner mailto:mail@joachim-breitner.de> wrote:
Dear Committee,
another status update, because why not.
A small reminder: These mails have two sections, one that’s a delta
since last status, but below is a summary of all proposals we have to
act on. Please at least scroll through that on each status mail to see
if you are listed, maybe you forgot something (or I made a mistake).
So here’s the delta since last month.
* GHC2021 defined! Yay!
* Bylaws merged! Yay
* Simon², Iavor, Richard and me had thus their terms expired.
The Simons, as key members, wanted to continue and were
   voted back in.
The others are now “expiring”, until the next nomination round
   concludes. Alejandro is going to run that process.
* we were asked to review these proposals:
   #390: Fine-grained pragmas, Shepherd: Vitaly
* we have a recommendation from the shepherd about:
   #368: Warn on prefix/suffix operators (accept)
* we have sent the following proposals back to revision
   - none -
* we decided about the following proposals
   #313: Delimited continuation primops (accept)
   #387: The Char kind (accept)
   #368: Warn on prefix/suffix operators (accept)
We currently have to act on the following 5 proposals, down by 2.
## Waiting for committee decision
#381: Visible 'forall' in types of terms, Shepherd: Iavor
      Recommendation was to reject, but discussion went into the more 
      abstract “whither dependent Haskell”. But what does this mean
      for this proposal?
      Iavor, can you pick this up again?
#369: Add sumToTag# primop, Shepherd: Eric
      Essentially accepted, waiting for feedback from the author on
      final tweaks. Eric, care to nudge the author, or just do it?
#302: \of, Shepherd: Cale
      No new discussion yet. It seems there was some confusion, which
      was cleared up by Tom, and Cale said he’ll pick it up now again.
## Waiting for Shepherd action
#367: Clarify primops using unboxed sums, Shepherd: Simon Marlow
      Simon said he’d reject it on the Github PR. Still waiting
      for the discussion to start on the mailing list.
#390: Fine-grained pragmas, Shepherd: Vitaly
      Still kinda new, but a recommendation would be good soon.
Cheers,
Joachim
-- 
Joachim Breitner
  mail@joachim-breitner.de mailto:mail@joachim-breitner.de
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