Records in Haskell

[Greg Weber]

I am willing to help on this as much as I can. Unfortunately I don't think
you want me to lead the discussion or make decisions on this - many of
these discussions seem over my head. I will continue to study them though
and see if the sink in more.

I do think almost all of these proposals want a dot selector, so it is a
good idea for Haskell to require the normal function (composition) dot to
have spaces around it - should this be brought to the Haskell
Prime committee?

Greg Weber

On Fri, Dec 23, 2011 at 1:52 PM, Simon Peyton-Jones
<simonpj at microsoft.com>wrote:

>  Are Records stalled out again? I am perfectly willing to leave the fate
> of records up to a willing and capable implementer. That seems much better
> than waiting another 5 years for perfection :)****
>
> ** **
>
> Yes, they are stalled again.  The “simple solution” turned out to be not
> simple.  I wrote it up at length in ****
>
>
> http://hackage.haskell.org/trac/ghc/wiki/Records/OverloadedRecordFields***
> *
>
> There are various unsatisfactory aspects of the proposal, particularly
> concerning record update.  I am not sure how to resolve them. ****
>
> ** **
>
> There was essentially no reaction.  As it’s quite a lot of work to
> implement, and no one seemed to care very much, I put it back on the back
> burner.   So that’s where it stands.****
>
> ** **
>
> Meanwhile, AntC has put forth another proposal that I have not had time to
> look at in detail.****
>
>
> http://www.haskell.org/pipermail/glasgow-haskell-users/2011-December/021298.html
> ****
>
> ** **
>
> *What this needs is someone (not me) to lead the discussion and try to
> make sure it makes progress*.  For example, does AntC’s proposal work? Is
> it better than the one I articulated?  Are any other variants worth
> considering? Is the gain from overloading record fields worth the pain or
> design and implementation?    Volunteers, stand forth!****
>
> ** **
>
> Simon****
>
> ** **
>
> ** **
>
> *From:* Greg Weber [mailto:greg at gregweber.info]
> *Sent:* 09 December 2011 19:38
> *To:* Simon Peyton-Jones
> *Cc:* Wolfgang Jeltsch; glasgow-haskell-users at haskell.org
>
> *Subject:* Re: Records in Haskell****
>
>  ** **
>
> Are Records stalled out again? I am perfectly willing to leave the fate of
> records up to a willing and capable implementer. That seems much better
> than waiting another 5 years for perfection :)****
>
> ** **
>
> As an intermediate step, is it possible to put a warning in 7.4 when the
> dot operator is used without a space so that it can be reserved for usage
> with a records solution? Or will the new records solution be turned on by
> an extension anyways?****
>
> ** **
>
> On Mon, Nov 7, 2011 at 10:21 AM, Simon Peyton-Jones <simonpj at microsoft.com>
> wrote:****
>
> | would inclusion of such a record system into GHC mean that plans for
> | first-class labels (<http://tinyurl.com/7fppj32>) are abandoned? That
> | would be a pity, since first-class labels are very useful to implement
> | record systems that go beyond what the abovementioned record system
> | provides. See, for example, my work on records:
> |      <
> http://www.informatik.tu-cottbus.de/~jeltsch/research/ppdp-2010-paper.pdf>
> |      <http://hackage.haskell.org/package/records>****
>
> The story is summarised at
>        http://hackage.haskell.org/trac/ghc/wiki/Records
>
> First-class labels are one point in the vast swamp of competing and
> overlapping proposals for records.  I think they are summarise here:
>        http://hackage.haskell.org/trac/ghc/wiki/ExtensibleRecords
> I am unsure which of this list of proposals you are referring to. The URL
> you quote is this
>        http://hackage.haskell.org/trac/haskell-prime/wiki/FirstClassLabels
> but it doesn't seem to actually contain a design, merely some options for
> a design that is implicit.  If you do have a design you advocate, it would
> be good to add it to the list at
>        http://hackage.haskell.org/trac/ghc/wiki/ExtensibleRecords
> perhaps explaining which of the other members of the list it subsumes.
>
> Because there are so many proposals I have not gone ahead with any of
> them.  The most recent thread, articulated at
>        http://hackage.haskell.org/trac/ghc/wiki/Records
> is to ask what is the *smallest change* that would solve the *most
> pressing problem*, namely the inability to use the same field name in
> different records.  First class labels is (I assume) much more ambitious.
>  But maybe not.
>
> Anything you can do to bring clarity to the swamp, by editing the above
> two pages, would be a great service to the community.  At the moment, we
> are stuck in an infinite loop.
>
> Simon****
>
>
> _______________________________________________
> Glasgow-haskell-users mailing list
> Glasgow-haskell-users at haskell.org
> http://www.haskell.org/mailman/listinfo/glasgow-haskell-users****
>
> ** **
>
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