/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.'System.IO.Streams.read' :: 'System.IO.Streams.InputStream' a -> IO (Maybe a) \-\- push an item back to an input stream Streams.'System.IO.Streams.unRead' :: a -> 'System.IO.Streams.InputStream' a -> IO () \-\- write to an output stream Streams.'System.IO.Streams.write' :: Maybe a -> 'System.IO.Streams.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. /ChangeLog/ [@184.108.40.206@] Fixed a build error with network versions older than 2.4. [@220.127.116.11@] @System.IO.Streams.Network@: scalability improvement: buffers for socket reads are now allocated by system malloc rather than by pinned pointers in GHC (currently pinned pointer allocation takes a global lock). [@18.104.22.168@] Widened @attoparsec@ and @text@ library dependencies to allow the latest versions. [@22.214.171.124@] Added @System.IO.Streams.ByteString.takeExactly@. Widened @network@ dependency to include 2.3. Added a @NoInteractiveTests@ flag to selectively disable some tests for environments where spawning interactive processes is impossible. [@126.96.36.199@] Allowed newest versions of the @process@, @test-framework@, and @text@ libraries. [@188.8.131.52@] Fixed build error when compiled against attoparsec-0.10.0.x. [@184.108.40.206@] Added @System.IO.Streams.Concurrent.makeChanPipe@, to create a simple concurrent pipe between an @InputStream@/@OutputStream@ pair. [@220.127.116.11@] Added @System.IO.Streams.Network.socketToStreamsWithBufferSize@, allowing control over the size of the receive buffers used when reading from sockets. [@18.104.22.168@] Fixed an inconsistent version upper bound in the test suite. [@22.214.171.124@] Fixed a typo in the tutorial. [@126.96.36.199@] A couple of Haddock markup fixes. [@188.8.131.52@] Reworked, simplified, and streamlined the internals of the library. Exports from "System.IO.Streams.Internal" relying on Sources and Sinks were deleted because they are no longer necessary: Source(..), Sink(..), defaultPushback, withDefaultPushback, nullSource, nullSink, singletonSource, simpleSource, sourceToStream, sinkToStream, generatorToSource, and consumerToSink. [@184.108.40.206@] Fixed a bug in which \"takeBytes 0\" was erroneously requesting input from the wrapped stream. [@220.127.116.11@] Fixed a compile error on GHC 7.0.x. [@18.104.22.168@] Added "System.IO.Streams.Process" (support for communicating with system processes using streams), added new functions to "System.IO.Streams.Handle" for converting @io-streams@ types to 'System.IO.Handle's. (Now you can pass streams from this library to places that expect Handles and everything will work.) [@22.214.171.124@] Added 'System.IO.Streams.Combinators.ignoreEof'. [@126.96.36.199@] Fixed some haddock markup.