[Haskell-cafe] status and future of haskell98 and haskell2010 packages

Herbert Valerio Riedel hvr at gnu.org
Thu Oct 8 12:24:16 UTC 2015

On 2015-10-08 at 00:08:43 +0200, Andrey Chudnov wrote:
> My e-mail was rejected from libraries at haskell.org (the official
> maintenance contact of the two packages in question), so I'm trying my
> luck here instead. Hoping I can get some answers on the following
> questions:
> 1. What is the status of `haskell2010` and `haskell98` packages? Are
> they supported? Deprecated? In need of new maintainers?

Short answer: with GHC 7.10 it is not possible anymore to implement a
proper[1] `haskell98` or `haskell2010` package anymore.

More details can be found at https://ghc.haskell.org/ticket/9590

> 2. Assuming the answer to the previous question is "alive and well",
> are there any plans to release new versions of those for GHC 7.10 and
> beyond?

In order to be able to recover support for a `haskell2010` package in
newer GHCs, GHC will need to be extended in some way. I can think of two
different paths to pursue to accomplish this, depending on whether
type(classes) need to be shared with `base` or not. Moreover, it wasn't
clear how much actual demand there really is to have the recent GHCs
support a legacy `haskell2010` mode.

So if there's somebody interested in resuscitating a
`haskell98`/`haskell2010` package, please tell us what your use-case is
(to help understand whether type(class) sharing w/ `base` is essential
or not -- it's *much* more easier to get this working w/o the typeclass
sharing requirement, whereas the typeclass-sharing variant might not
even be possible at all)


 [1]: I.e. with the requirement that all code written conforming to the
      respective Haskell Report will be compileable via e.g.

      ghc -XHaskell2010 -hide-all-packages -package haskell2010 -c *.hs

      (to some degree, this was already broken before GHC 7.10
      due to the superclass-removal on `Num`, but with AMP this was
      broken beyond tolerance)

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