-- More comments, please. Bad names? Important missing functionality? -- Still unimplementable?
Basically I think this is good. I think the naming should be rethought, but that can be done later. I wanted to float a generalisation of this scheme, though. I'm wondering whether it might be a good idea to make InputStream and OutputStream into type classes, the advantage being that this makes streams more extensible - one example is that memory-mapped files fit neatly into this framework. I already have 6 examples of things that can have streams layered on top (or *are* streams), and there are almost certainly more. Here's some signatures for you to peruse: class Stream s where closeStream :: s -> IO () streamSetBuffering :: s -> BufferMode -> IO () streamGetBuffering :: s -> IO BufferMode streamFlush :: s -> IO () isEOS :: s -> IO Bool class InputStream s where streamGet :: s -> IO Word8 streamReadBuffer :: s -> Integer -> Buffer -> IO () streamGetBuffer :: s -> Integer -> IO ImmutableBuffer streamGetContents :: s -> IO [Word8] class OutputStream s where streamPut :: s -> Word8 -> IO () streamPuts :: s -> [Word8] -> IO () streamWriteBuffer :: s -> Integer -> Buffer -> IO () -- Files in the filesystem, with access rights data File data FileInputStream -- instance Stream, InputStream data FileOutputStream -- instance Stream, OutputStream -- Memory-mapped files mapFile :: File -> FileOffset -> Integer -> MapMode -> IO MappedFile data MappedFile data MappedFileInputStream -- instance Stream, InputStream data MappedFileOutputStream -- instance Stream, OutputStream instance MArray MappedFile Word8 IO -- so we can read/write it directly mappedFileInputStream :: MappedFile -> Integer -> Integer -> IO MappedFileInputStream mappedFileOutputStream :: MappedFile -> Integer -> Integer -> IO MappedFileOutputStream -- Pipes data Pipe -- a pipe with a read and a write end instance Stream Pipe instance InputStream Pipe instance OutputStream Pipe createPipe :: IO Pipe closePipe :: Pipe -> IO () -- Streams from arrays: data ArrayInputStream instance InputStream ArrayInputStream data ArrayOutputStream instance OutputStream ArrayOutputStream iarrayInputStream :: (Ix i, IArray a Word8) => a i Word8 -> i -> ArrayInputStream marrayInputStream :: (Ix i, MArray a Word8 IO) => a i Word8 -> i -> ArrayInputStream marrayOutputStream :: (Ix i, MArray a Word8 IO) => a i Word8 -> i -> ArrayOutputStream -- Sockets: data Socket instance Stream Socket instance InputStream Socket instance OutputStream Socket -- URIs: data URIStream getURI :: URI -> IO URIStream instance InputStream URIStream Cheers, Simon