[Haskell-cafe] [ANNOUNCE] GHC 8.2.1 available

[Wolfgang Jeltsch]

Hi!

I ran into the same problem.

Apparently, we need cabal-install 2.0, which has not been released yet.
A preliminary solution is to use the development version from the 2.0
branch. Binary packages can be found at

     http://ppa.launchpad.net/hvr/ghc/ubuntu/pool/main/c/cabal-install-2.0/  ,

for example. It is possible to extract the cabal-install executable from
these packages, so that it can be installed without using some Linux
distribution package manager.

All the best,
Wolfgang

Am Mittwoch, den 26.07.2017, 18:45 -0700 schrieb Evan Laforge:
> This seems like a silly question, but how can we install cabal-install
> now?  The latest hackage version 1.24.0.2 has Cabal (>=1.24.2 &&
> <1.25), but it looks like ghc Cabal is now at 2.*.
> 
> I ran into this because if I get:
> 
> % cabal install --only-dependencies
> Resolving dependencies...
> cabal: internal error when reading package index: failed to parse
> .cabal
> fileThe package index or index cache is probably corrupt. Running
> cabal update
> might fix it.
> 
> It seems to be triggered by having 'ekg' in the deps list, since if I
> take it out then I get some other errors about packages not liking the
> new base, which is true.  'ekg' also doesn't like the new base, but
> "internal error" is not the clearest way to express that :)
> 
> It's frustrating that cabal-install still doesn't report the parse
> error, even though the parse function returns one.  It just ignores
> the ParseFailed case.  I was going to try fixing it and send a pull
> request when I ran into the Cabal 2.* problem.
> 
> On Wed, Jul 26, 2017 at 7:15 AM, Ben Gamari <ben at smart-cactus.org>
> wrote:
> > 
> > Wolfgang Jeltsch <wolfgang-it at jeltsch.info> writes:
> > 
> > > 
> > > Am Samstag, den 22.07.2017, 23:03 -0400 schrieb Ben Gamari:
> > > > 
> > > > In addition, there are a number of new features,
> > > > 
> > > >  * A new, more type-safe type reflection mechanism
> > > > 
> > > >  * The long-awaited Backpack module system
> > > > 
> > > >  * Deriving strategies to disambiguate between GHC's various
> > > > instance
> > > >    deriving mechanisms
> > > > 
> > > >  * Unboxed sum types, for efficient unpacked representation of
> > > > sum
> > > >    data types
> > > > 
> > > >  * Compact regions, allowing better control over garbage
> > > > collection
> > > >    in the presence of large heaps containing many long-lived
> > > > objects.
> > > > 
> > > >  * Colorful messages and caret diagnostics for more legible
> > > > errors
> > > > 
> > > > A more thorough list of the changes in this release can be found
> > > > in
> > > > the release notes,
> > > > 
> > > >   https://haskell.org/ghc/docs/8.2.1/docs/html/users_guide/8.2.1
> > > > -notes.html
> > > It seems that the release notes mention the new type reflection
> > > mechanism und colorful messages only in the “Highlights” section,
> > > not in
> > > the “Full details” section, and that they do not mention the
> > > Backpack
> > > module system and unboxed sums at all.
> > > 
> > Yes, indeed these were oversights. They are fixed in the ghc-8.2
> > branch
> > and I will try to push newly generated documentation shortly.
> > 
> > Cheers,
> > 
> > - Ben
> > 
> > _______________________________________________
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> > Glasgow-haskell-users at haskell.org
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> > rs
> >