[Haskell-cafe] Binary I/O

[Stefan O'Rear]

On Mon, Apr 02, 2007 at 03:26:05PM +0100, Daniel Brownridge wrote:
> Hello.
> 
> I am a Computer Science student attempting to write an emulator using 
> Haskell.
> One of my main design choices is how to deal with machine code.
> Clearly it is possible to represent 0's and 1's as ASCII characters, 
> however it strikes me that it would be much nicer to the I/O using raw 
> binary. I don't seem to be able to find much documentation on this.
> Does anybody know how it's done, or can point me in the direction of 
> some resources.

The current Big Name in Haskell's binary support is the aptly named
'binary' library, available from hackagedb
(http://hackage.haskell.org/cgi-bin/hackage-scripts/package/binary-0.3). 

binary works using two sets of functions, one for very efficiently
building binary bytestrings (like [Char] -> [Char]):

data Builder --abstract
empty, append -- monoid ops
singleton :: Word8 -> Builder
putWord16be :: Word8 -> Builder
...
toLazyByteString :: Builder -> ByteString

and a monad for parsing binary data:

data Get a -- abstract
getWord8 :: Get Word8
getWord16be :: Get Word16
...
runGet :: Get a -> ByteString -> a

(there's also a higher level interface paterned on Read/Show, but I
don't think that's applicable here). 

Stefan