ANNOUNCE: GHC version 6.12.1

Simon Marlow marlowsd at
Tue Dec 15 04:57:46 EST 2009

On 14/12/09 19:04, Jost Berthold wrote:
> Luca,
> to use Control.Parallel, you need to download and install two packages,
> deepseq and parallel, from
> Most likely this will work with cabal, or you just download the two
> tarballs .

cabal install parallel

(assuming you have a working cabal-install)

> The reason is, when packaging "parallel", this package has been removed
> from the GHC core libraries. BTW I am unsure whether this is at all
> clever, since it needs specific GHC support (at least for now - am I
> right here?)
> In addition, be informed that Control.Parallel.Strategies has been
> heavily restructured just last month (splitting it into deepseq and
> parallel is one of the changes, but not the most fundamental).
> If you want to try examples from GpH publications, you will certainly
> have some problems. parallel-1.x versions containing the original
> definitions are on hackage as well and should work for experiments.

I think it would be a good idea to have a wiki page describing the 
differences between the API used in those papers and the current API. 
Off the top of my head, the main differences are:

  * import Control.Parallel.Strategies, not import Strategies
  * seq is now pseq
  * rnf is now rdeepseq
  * don't use demanding, sparking

Better still would be a selection of recipes or patterns for 
parallelising Haskell code.

Anyone feel like tackling this? (I realise I'm the obvious person to do 
it, but I'm deep in mid-hack on the parallel GC and don't want to get 
too distracted right now).


More information about the Glasgow-haskell-users mailing list