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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
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<pkgmetadata>
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<maintainer type="project">
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<email>haskell@gentoo.org</email>
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<name>Gentoo Haskell</name>
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</maintainer>
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<use>
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<flag name="network">Include network support</flag>
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<flag name="zlib">Include zlib support</flag>
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</use>
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<longdescription>
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/Overview/
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The io-streams library contains simple and easy-to-use primitives for I/O
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using streams. Most users will want to import the top-level convenience
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module "System.IO.Streams", which re-exports most of the library:
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@
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import System.IO.Streams (InputStream, OutputStream)
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import qualified System.IO.Streams as Streams
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@
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For first-time users, @io-streams@ comes with an included tutorial, which can
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be found in the "System.IO.Streams.Tutorial" module.
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/Features/
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The @io-streams@ user API has two basic types: @InputStream a@ and
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@OutputStream a@, and three fundamental I/O primitives:
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@
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\-\- read an item from an input stream
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Streams.read :: InputStream a -> IO (Maybe a)
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\-\- push an item back to an input stream
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Streams.unRead :: a -> InputStream a -> IO ()
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\-\- write to an output stream
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Streams.write :: Maybe a -> OutputStream a -> IO ()
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@
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Streams can be transformed by composition and hooked together with provided combinators:
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@
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ghci> Streams.fromList [1,2,3::Int] >>= Streams.map (*10) >>= Streams.toList
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[10,20,30]
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@
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Stream composition leaves the original stream accessible:
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@
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ghci> input \<- Streams.fromByteString \"long string\"
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ghci> wrapped \<- Streams.takeBytes 4 input
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ghci> Streams.read wrapped
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Just \"long\"
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ghci> Streams.read wrapped
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Nothing
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ghci> Streams.read input
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Just \" string\"
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@
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Simple types and operations in the IO monad mean straightforward and simple
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exception handling and resource cleanup using Haskell standard library
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facilities like 'Control.Exception.bracket'.
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@io-streams@ comes with:
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* functions to use files, handles, concurrent channels, sockets, lists,
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vectors, and more as streams.
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* a variety of combinators for wrapping and transforming streams, including
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compression and decompression using zlib, controlling precisely how many
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bytes are read from or written to a stream, buffering output using
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bytestring builders, folds, maps, filters, zips, etc.
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* support for parsing from streams using @attoparsec@.
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* support for spawning processes and communicating with them using streams.
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</longdescription>
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</pkgmetadata>
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