Hi Malcolm, Withdrawing the packages from GHC's distribution is certainly a possibility. We did briefly raise that point when we talked yesterday too, but it wasn't discussed much.
Perhaps some others feel the same, but I imagine more people would be OK with #2 above as opposed to eliminating it, since we already lightly break some things anyway. Hopefully we'll really find out soon. On Tue, Sep 30, 2014 at 4:00 PM, Malcolm Wallace <malcolm.wall...@me.com> wrote: > How about doing the honest thing, and withdrawing both packages in ghc-7.10? > Haskell'98 is now 15 years old, and the 2010 standard was never really > popular anyway. > > Regards, > Malcolm > > On 30 Sep 2014, at 21:21, Austin Seipp <aus...@well-typed.com> wrote: > > Hello developers, users, friends, > > I'd like you all to weigh in on something - a GHC bug report, that has > happened as a result of making Applicative a superclass of Monad: > > https://ghc.haskell.org/trac/ghc/ticket/9590 > > The very condensed version is this: because haskell2010/haskell98 > packages try to be fairly strictly conforming, they do not have > modules like Control.Applicative. > > Unfortunately, due to the way these packages are structured, many > things are simply re-exported from base, like `Monad`. But > `Applicative` is not, and cannot be imported if you use -XHaskell2010 > and the haskell2010 package. > > The net result here is that haskell98/haskell2010 are hopelessly > broken in the current state: it's impossible to define an instance of > `Monad`, because you cannot define an instance of `Applicative`, > because you can't import it in the first place! > > This leaves us in quite a pickle. > > So I ask: Friends, what do you think we should do? I am particularly > interested in users/developers of current Haskell2010 packages - not > just code that may *be* standard Haskell - code that implies a > dependency on it. > > There was a short discussion between me and Simon Marlow about this in > the morning, and again on IRC this morning between me, Duncan, Edward > K, and Herbert. > > Basically, I only see one of two options: > > - We could make GHC support both: a version of `Monad` without > `Applicative`, and one with it. This creates some complication in the > desugarer, where GHC takes care of `do` syntax (and thus needs to be > aware of `Monad`'s definition and location). But it is, perhaps, quite > doable. > > - We change both packages to export `Applicative` and follow the API > changes in `base` accordingly. > > Note that #1 above is contingent on three things: > > 1) There is interest in this actually happening, and these separate > APIs being supported. If there is not significant interest in > maintaining this, it's unclear if we should go for it. > > 2) It's not overly monstrously complex (I don't think it necessarily > will be, but it might be.) > > 3) You can't like `haskell2010` packages and `base` packages together > in the general case, but, AFAIK, this wasn't the case before either. > > I'd really appreciate your thoughts. This must be sorted out for 7.10 > somehow; the current situation is hopelessly busted. > > -- > Regards, > > Austin Seipp, Haskell Consultant > Well-Typed LLP, http://www.well-typed.com/ > _______________________________________________ > Glasgow-haskell-users mailing list > Glasgow-haskell-users@haskell.org > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users > _______________________________________________ > ghc-devs mailing list > ghc-d...@haskell.org > http://www.haskell.org/mailman/listinfo/ghc-devs > -- Regards, Austin Seipp, Haskell Consultant Well-Typed LLP, http://www.well-typed.com/ _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
