Modulepipes-safe-2.3.5Haskell2010

Pipes.Safe.Prelude

Simple resource management functions

8 values

Packagepipes-safe-2.3.5
Exports8
LanguageHaskell2010
LicenceBSD-3-Clause
SourcePrelude.hs

Handle management

4 declarations

valuewithFile :: MonadSafe m => FilePath -> IOMode -> (Handle -> m r) -> m r

Acquire a Handle within MonadSafe

The file is opened in text mode. See also: withBinaryFile

valuewithBinaryFile

:: MonadSafe m
=> FilePath
-> IOMode
-> Handle -> m r
-> m r

Like withFile, but open the file in binary mode

See System.IO.hSetBinaryMode for the differences between binary and text mode.

valueopenFile :: MonadSafe m => FilePath -> IOMode -> m (ReleaseKey, Handle)

Acquire a Handle within MonadSafe

The ReleaseKey can be used to close the handle with release; otherwise the handle will be closed automatically at the conclusion of the MonadSafe block.

The file is opened in text mode. See also: openBinaryFile

valueopenBinaryFile

:: MonadSafe m
=> FilePath
-> IOMode
-> m (ReleaseKey, Handle)

Like openFile, but open the file in binary mode

See System.IO.hSetBinaryMode for the differences between binary and text mode.

String I/O

2 declarations

Note that Strings are very inefficient, and I will release future separate packages with ByteString and Text operations. I only provide these to allow users to test simple I/O without requiring any additional library dependencies.

valuereadFile :: MonadSafe m => FilePath -> Producer' String m ()

Read lines from a file, automatically opening and closing the file as necessary

valuewriteFile :: MonadSafe m => FilePath -> Consumer' String m r

Write lines to a file, automatically opening and closing the file as necessary

Registering/releasing

2 declarations

valueallocate

:: MonadSafe m
=> Base m a
Acquire
-> (a -> Base m ())
Release
-> m (ReleaseKey, a)

Acquire some resource with a guarantee that it will eventually be released

The ReleaseKey can be passed to release to release the resource manually. If this has not been done by the end of the MonadSafe block, the resource will be released automatically.

valueallocate_

:: MonadSafe m
=> Base m a
Acquire
-> Base m ()
Release
-> m ReleaseKey

Like allocate, but for when the resource itself is not needed

The acquire action runs immediately. The ReleaseKey can be passed to release to run the release action. If this has not been done by the end of the MonadSafe block, the release action will be run automatically.