[Haskell-cafe] containers-deepseq?

Joachim Breitner mail at joachim-breitner.de
Tue Nov 29 09:29:21 CET 2011


Am Dienstag, den 29.11.2011, 07:43 +0200 schrieb Michael Snoyman:
> Since the release of deepseq 1.2, we've had a bit of a problem: when
> using the newest versions of packages on Hackage, there is no NFData
> instance available for the containers types. When GHC 7.4 comes out
> with its newer version of containers, this will be addressed, but
> we'll still have problems for users of older GHC releases.
> I'd like to suggest a solution: a new package called
> containers-deepseq. Using conditional compilation, it will provide an
> orphans NFData instance for all containers types when deepseq >= 1.2
> and containers < 0.5. Packages (e.g., aeson) would then depend on
> containers-deepseq and simply import the module whenever they rely on
> the NFData instances. When GHC 7.4 comes out, the package will
> essentially be a no-op.
> Does this make sense?

from a distro point of view: Please void this if possible; every
additional package causes us work. (Although we’d likely just not
upgrade containers before 7.4.1 and patch out the dependency in the
cabal file when we switch to 7.4.1.)

Why can’t you put the instances in containers, guarded by some #ifs? I
don’t see the point of a separate package for these 15 lines of code.


Joachim "nomeata" Breitner
  mail at joachim-breitner.de  |  nomeata at debian.org  |  GPG: 0x4743206C
  xmpp: nomeata at joachim-breitner.de | http://www.joachim-breitner.de/

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