Henning Thielemann wrote:
On Sun, 17 Feb 2008, Jed Brown wrote:
On Fri, 15 Feb 2008, Jed Brown wrote:
I propose that the following instance be added to base:
instance (RealFloat a, Storable a) => Storable (Complex a) where sizeOf z = 2 * sizeOf (realPart z) alignment z = sizeOf (realPart z) peek p = do [r,i] <- peekArray 2 (castPtr p) return (r :+ i) poke p (r :+ i) = pokeArray (castPtr p) [r,i]
This instance is binary compatible with C99, C++ and Fortran complex types.
It is currently needed by at least two independent packages: hmatrix and fft. Since it is natural for user code to use both of these packages, we need to move the instance to a common location.
http://hackage.haskell.org/trac/ghc/ticket/2099 I also need it for signal processing. In light of the fact that several packages need this instance, I created a package storable-complex (on Hackage) which has the instance in Foreign.Storable.Complex. In the interest of enabling our packages to
On 15 Feb 2008, lemming@henning-thielemann.de wrote: play nicely *now*, I would like to encourage everyone needing this instance to get it from this common source. When it (hopefully) makes it into base, we can use a flag in the .cabal file to get it from base instead of this package.
an instance for pairs would also be nice ... :-)
I see the smiley, but just in case you're serious: that's pretty hard to get right. Presumably you want it to match the C struct layout rules according to the C ABI of the current platform, which means implementing the layout rules correctly. Cheers, Simon