Converting things to and from binary

[Derek Elkins]

On 20 May 2003 09:07:24 +0200
ketil@ii.uib.no (Ketil Z. Malde) wrote:

> Glynn Clements <glynn.clements@virgin.net> writes:
> 
> > George Russell wrote:
> 
> >> The general problem to solve is "How to we convert things to and
> >> from a binary format, so they can be efficiently written to and
> >> from disk".  I have solved this (incompletely) twice myself,
> 
> > Possibly the best way to handle this would be to extend the Storable
> > class, e.g. 
> 
> > class Storable a where
>           :
> [snip]    :
> > 	toByteArray :: a -> Array Int Word8
> > 	fromByteArray :: Array Int Word8 -> a
> 
> I wonder if this could be used to address a question (or perhaps
> "frustration" is a better term), namely that of efficient packing of
> data structures in memory.
> 
> Would it be possible to separate binary I/O in two layers, the binary
> layer converting to/from (U?)Arrays of Word8, and another, the I/O
> layer, reading and writing such arrays?  
> 
> Something almost entirely, but not quite, unlike:
> 
>         class Binary a where
>                 toBin :: a -> Array Int Word8
>                 toBinList :: [a] -> Array Int Word8
>                 fromBin :: Array Int Word8 -> a  -- perhaps with
>                 offset? fromBinList :: Array Int Word8 -> [a]
> 
>         hPutArray :: Handle -> Array Int Word8 -> IO ()
>         hGetArray :: ...
>         writeBinaryFile :: FilePath -> Array Int Word8 -> IO ()
>         :
>         
> -kzm

What's wrong with NHC's Binary/BinArray library?  There seems to be a
GHC port on the GreenCard page.