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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE pkgmetadata SYSTEM "http://www.gentoo.org/dtd/metadata.dtd">
<pkgmetadata>
<maintainer type="project">
<email>haskell@gentoo.org</email>
<name>Gentoo Haskell</name>
</maintainer>
<use>
<flag name="network">Include network support</flag>
<flag name="zlib">Include zlib support</flag>
</use>
<longdescription>
/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.
</longdescription>
</pkgmetadata>
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