Anyone trying to do any of this?
I've done some work in this area. I'm particularly interested in manipulating ASN.1 in haskell. Actually, my first use of Parsec was an ASN.1 parser. I'd done one previously in Spirit (the Boost C++ rip-off of parsec), but semantic actions were horrible in the extreme. Mmmm Parsec. In the indexing system I'm currently building in Haskell for my day job, I'm serializing several data structures, and using Data.Bits and Data.ByteString heavily. I was using HaXml, but I found it was very slow. So instead, I'm using an internal (within the indexing system) representation that is more akin to WBXML: import Data.ByteString as ByteString import Data.List as List import Data.Sequence as Seq data DocTree = DocElem ByteString [(ByteString,ByteString)] [DocTree] | DocText ByteString serialize tree = ByteString.concat $ Seq.toList $ execState (serialize' tree) Seq.empty serialize' (DocText txt) = do stuff <- get put (stuff |> pack [0]) putStr txt serialize' (DocElem name attrs kids) = do stuff <- get put (stuff |> pack [1]) putStr name putNum (List.length attrs) mapM_ (putPair putStr putStr) attrs putNum (List.length kids) mapM_ serialize' kids putStr .... You get the idea. Actually, the *real* code is trickier - it grovels first to find all the element names and numbers them. Likewise with attribute names (per element). The extra grovel is well worth it - it takes a little longer to serialize, but is more compact and deserializes quicker. Also worth noting - whether you compile a dictionary of element names or not, the result is much much much more space efficient than using HaXml, since it can all be decoded out of a single ByteString containing the document tree, with no actual string copying at all. That's the kind of [de]serialization I like. :-) Mind you, I still have to use HaXml when I first read documents into the system, and a very nice job it does too. T. -- Dr Thomas Conway [EMAIL PROTECTED] Silence is the perfectest herald of joy: I were but little happy, if I could say how much. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
