Bayley, Alistair wrote:
From: libraries-bounces@haskell.org [mailto:libraries-bounces@haskell.org] On Behalf Of Ketil Malde
Somebody raised the question of reading a Content-type field, etc: would it be possible to "rewind" a handle after setting encoding? For Content-type fields, I suspect the header is usually limited to ASCII anyway, so adding decoding for subsequent text is probably sufficient.
I think this is relevant:
http://www.haskell.org/pipermail/haskell-cafe/2004-September/006801.html
We've talked a lot in the past about a stream-layering IO abstraction. I'd forgotten about Oleg's post, thanks. Here are some others. There's the prototype I worked on: http://www.haskell.org/~simonmar/io/System.IO.html There's Bulat's Stream library, which is pretty complete: http://haskell.org/haskellwiki/Library/Streams And Takano Akio's version, in which he divides the type classes into smaller pieces. This is closer to the direction I thought we should go: http://yogimo.sakura.ne.jp/ssc/ Right now though, I'm not sure all this is going in the right direction. Dealing with all those mutable buffers is quite a headache (for the library writer, not the user), and lazy bytestrings have shown us that there are simpler ways to get good I/O performance. What's more, as Duncan Coutts has pointed out to me on more than one occasion, it's much easier to layer streams when the streams are lazy lists. As much as I hate to say it, there's a lot to be said for lazy I/O in this respect. However, lazy I/O has other problems - deterministically catching errors, unpredictable resource usage, unpredictable interaction with other I/O, and so on. Is there a nice solution? Something else we might look at is Oleg's left folds: http://okmij.org/ftp/Haskell/#fold-stream http://www.haskell.org/pipermail/haskell/2003-September/012741.html Cheers, Simon