haskell@gentoo.org Gentoo Haskell Include network support Include zlib support /Overview/ The io-streams library contains simple and easy-to-use primitives for I/O using streams. Most users will want to import the top-level convenience module "System.IO.Streams", which re-exports most of the library: @ import System.IO.Streams (InputStream, OutputStream) import qualified System.IO.Streams as Streams @ For first-time users, @io-streams@ comes with an included tutorial, which can be found in the "System.IO.Streams.Tutorial" module. /Features/ The @io-streams@ user API has two basic types: @InputStream a@ and @OutputStream a@, and three fundamental I/O primitives: @ \-\- read an item from an input stream Streams.read :: InputStream a -> IO (Maybe a) \-\- push an item back to an input stream Streams.unRead :: a -> InputStream a -> IO () \-\- write to an output stream Streams.write :: Maybe a -> OutputStream a -> IO () @ Streams can be transformed by composition and hooked together with provided combinators: @ ghci> Streams.fromList [1,2,3::Int] >>= Streams.map (*10) >>= Streams.toList [10,20,30] @ Stream composition leaves the original stream accessible: @ ghci> input \<- Streams.fromByteString \"long string\" ghci> wrapped \<- Streams.takeBytes 4 input ghci> Streams.read wrapped Just \"long\" ghci> Streams.read wrapped Nothing ghci> Streams.read input Just \" string\" @ Simple types and operations in the IO monad mean straightforward and simple exception handling and resource cleanup using Haskell standard library facilities like 'Control.Exception.bracket'. @io-streams@ comes with: * functions to use files, handles, concurrent channels, sockets, lists, vectors, and more as streams. * a variety of combinators for wrapping and transforming streams, including compression and decompression using zlib, controlling precisely how many bytes are read from or written to a stream, buffering output using bytestring builders, folds, maps, filters, zips, etc. * support for parsing from streams using @attoparsec@. * support for spawning processes and communicating with them using streams.