IO +System

data IO a :: * -> *
base Prelude, base System.IO
A value of type IO a is a computation which, when performed, does some I/O before returning a value of type a. There is really only one way to "perform" an I/O action: bind it to Main.main in your program. When your program is run, the I/O will be performed. It isn't possible to perform I/O from an arbitrary function, unless that function is itself in the IO monad and called at some point, directly or indirectly, from Main.main. IO is a monad, so IO actions can be combined using either the do-notation or the >> and >>= operations from the Monad class.
type IOError = IOException
base Prelude, base System.IO.Error
The Haskell 98 type for exceptions in the IO monad. Any I/O operation may raise an IOError instead of returning a result. For a more general type of exception, including also those that arise in pure code, see Control.Exception.Exception. In Haskell 98, this is an opaque type.
ioError :: IOError -> IO a
base Prelude, base Control.Exception.Base, base Control.Exception, base System.IO.Error, base Control.OldException
Raise an IOError in the IO monad.
type IOCallback = FdKey -> Event -> IO ()
base System.Event
Callback invoked on I/O events.
ioeGetErrorString :: IOError -> String
base System.IO.Error
ioeGetErrorType :: IOError -> IOErrorType
base System.IO.Error
ioeGetFileName :: IOError -> Maybe FilePath
base System.IO.Error
ioeGetHandle :: IOError -> Maybe Handle
base System.IO.Error
ioeGetLocation :: IOError -> String
base System.IO.Error
data IOErrorType
base System.IO.Error
An abstract type that contains a value for each variant of IOError.
ioeSetErrorString :: IOError -> String -> IOError
base System.IO.Error
ioeSetErrorType :: IOError -> IOErrorType -> IOError
base System.IO.Error
ioeSetFileName :: IOError -> FilePath -> IOError
base System.IO.Error
ioeSetHandle :: IOError -> Handle -> IOError
base System.IO.Error
ioeSetLocation :: IOError -> String -> IOError
base System.IO.Error
data IOMode
base System.IO
See System.IO.openFile
module System.IO
base System.IO
The standard IO library.
package io-capture
package
capture IO action's stdout and stderr Version 0.3
package io-choice
package
Choice for IO and lifted IO Version 0.0.1
package io-memoize
package
Transform an IO action into a similar IO action that performs the original action only once. You can choose to perform the original action in one of three ways: * lazily (might never be performed) * eagerly * concurrently (eager) Special thanks to shachaf and headprogrammingczar from #haskell irc for helping me reason about the behavior of this library. Version 1.0.0.0

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