System.Console.Readline

A Haskell binding to the GNU readline library. The GNU Readline library provides a set of functions for use by applications that allow users to edit command lines as they are typed in. By default, the line editing commands are similar to those of emacs. A vi-style line editing interface is also available.

An example of a typical use of readline with history functionality is illustrated in the following read, eval, print loop:

 readEvalPrintLoop :: IO ()
 readEvalPrintLoop = do
   maybeLine <- readline "% "
   case maybeLine of 
    Nothing     -> return () -- EOF / control-d
    Just "exit" -> return ()
    Just line -> do addHistory line
                    putStrLn $ "The user input: " ++ (show line)
                    readEvalPrintLoop

Documentation

readline

Arguments

:: String

prompt

-> IO (Maybe String)

returns the line the user input, or Nothing if EOF is encountered.

readline is similar to System.IO.getLine, but with rich edit functionality and history capability. readline will read a line from the terminal and return it, using prompt as a prompt. If prompt is the empty string, no prompt is issued. The line returned has the final newline removed, so only the text of the line remains. A blank line returns the empty string. If EOF is encountered while reading a line, and the line is empty, Nothing is returned. If an EOF is read with a non-empty line, it is treated as a newline.

addHistory :: String -> IO ()

Add this command to the history. This allows users to search backward through history with C-r and step through with up and down arrows, among other things.

getLineBuffer :: IO String

setLineBuffer :: String -> IO ()

getPoint :: IO Int

setPoint :: Int -> IO ()

getEnd :: IO Int

setEnd :: Int -> IO ()

getMark :: IO Int

setMark :: Int -> IO ()

setDone :: Bool -> IO ()

setPendingInput :: Char -> IO ()

setEraseEmptyLine :: Bool -> IO ()

getPrompt :: IO String

setAlreadyPrompted :: Bool -> IO ()

getLibraryVersion :: IO String

getTerminalName :: IO String

setReadlineName :: String -> IO ()

getInStream :: IO Handle

getOutStream :: IO Handle

setStartupHook :: Maybe (IO ()) -> IO ()

setPreInputHook :: Maybe (IO ()) -> IO ()

setEventHook :: Maybe (IO ()) -> IO ()

setRedisplayFunction :: Maybe (IO ()) -> IO ()

data Keymap

newBareKeymap :: IO Keymap

copyKeymap :: Keymap -> IO Keymap

newKeymap :: IO Keymap

freeKeymap :: Keymap -> IO ()

getKeymap :: IO Keymap

setKeymap :: Keymap -> IO ()

getKeymapByName :: String -> IO Keymap

getKeymapName :: Keymap -> IO (Maybe String)

getExecutingKeymap :: IO Keymap

getBindingKeymap :: IO Keymap

type Callback = Int -> Char -> IO Int

addDefun :: String -> Callback -> Maybe Char -> IO ()

bindKey :: Char -> Callback -> IO ()

bindKeyInMap :: Char -> Callback -> Keymap -> IO ()

unbindKey :: Char -> IO ()

unbindKeyInMap :: Char -> Keymap -> IO ()

unbindCommandInMap :: String -> Keymap -> IO ()

data Entry

Constructors

Function Callback

Macro String

Keymap Keymap

genericBind :: String -> Entry -> Keymap -> IO ()

parseAndBind :: String -> IO ()

readInitFile :: String -> IO ()

namedFunction :: String -> IO (Maybe Callback)

functionOfKeyseq :: String -> Maybe Keymap -> IO Entry

functionDumper :: Bool -> IO ()

listFunmapNames :: IO ()

funmapNames :: IO [String]

beginUndoGroup :: IO ()

endUndoGroup :: IO ()

data UndoCode

Constructors

UndoDelete

UndoInsert

UndoBegin

UndoEnd

addUndo :: UndoCode -> Int -> Int -> String -> IO ()

freeUndoList :: IO ()

doUndo :: IO Bool

modifying :: Int -> Int -> IO ()

redisplay :: IO ()

forcedUpdateDisplay :: IO ()

onNewLine :: IO ()

onNewLineWithPrompt :: IO ()

resetLineState :: IO ()

message :: String -> IO ()

clearMessage :: IO ()

savePrompt :: IO ()

restorePrompt :: IO ()

insertText :: String -> IO ()

deleteText :: Int -> Int -> IO ()

copyText :: Int -> Int -> IO String

killText :: Int -> Int -> IO ()

readKey :: IO Char

stuffChar :: Char -> IO Bool

initialize :: IO ()

resetTerminal :: Maybe String -> IO ()

ding :: IO Bool

displayMatchList :: [String] -> IO ()

callbackHandlerInstall :: String -> (String -> IO ()) -> IO (IO ())

callbackReadChar :: IO ()

setCatchSignals :: Bool -> IO ()

getCatchSignals :: IO Bool

setCatchSigwinch :: Bool -> IO ()

getCatchSigwinch :: IO Bool

cleanupAfterSignal :: IO ()

freeLineState :: IO ()

resetAfterSignal :: IO ()

resizeTerminal :: IO ()

setSignals :: IO ()

clearSignals :: IO ()

completeInternal :: Char -> IO ()

complete :: Int -> Char -> IO Int

possibleCompletions :: Int -> Char -> IO Int

insertCompletions :: Int -> Char -> IO Int

completionMatches :: String -> (String -> IO [String]) -> IO (Maybe (String, [String]))

filenameCompletionFunction :: String -> IO [String]

usernameCompletionFunction :: String -> IO [String]

setCompletionEntryFunction :: Maybe (String -> IO [String]) -> IO ()

setAttemptedCompletionFunction :: Maybe (String -> Int -> Int -> IO (Maybe (String, [String]))) -> IO ()

setFilenameQuotingFunction :: Maybe (String -> Bool -> Ptr CChar -> IO String) -> IO ()

quoteFilename :: String -> Bool -> Ptr CChar -> IO String

setFilenameDequotingFunction :: Maybe (String -> Maybe Char -> IO String) -> IO ()

setCharIsQuotedP :: Maybe (String -> Int -> IO Bool) -> IO ()

getCompletionQueryItems :: IO Int

setCompletionQueryItems :: Int -> IO ()

getBasicWordBreakCharacters :: IO String

setBasicWordBreakCharacters :: String -> IO ()

getBasicQuoteCharacters :: IO String

setBasicQuoteCharacters :: String -> IO ()

getCompleterWordBreakCharacters :: IO String

setCompleterWordBreakCharacters :: String -> IO ()

getCompleterQuoteCharacters :: IO String

setCompleterQuoteCharacters :: String -> IO ()

getFilenameQuoteCharacters :: IO String

setFilenameQuoteCharacters :: String -> IO ()

getSpecialPrefixes :: IO String

setSpecialPrefixes :: String -> IO ()

getCompletionAppendCharacter :: IO (Maybe Char)

setCompletionAppendCharacter :: Maybe Char -> IO ()

setIgnoreCompletionDuplicates :: Bool -> IO ()

getIgnoreCompletionDuplicates :: IO Bool

setFilenameCompletionDesired :: Bool -> IO ()

getFilenameCompletionDesired :: IO Bool

setFilenameQuotingDesired :: Bool -> IO ()

getFilenameQuotingDesired :: IO Bool

setInhibitCompletion :: Bool -> IO ()

getInhibitCompletion :: IO Bool

setAttemptedCompletionOver :: Bool -> IO ()

getAttemptedCompletionOver :: IO Bool

setIgnoreSomeCompletionsFunction :: Maybe ([String] -> IO [String]) -> IO ()

setDirectoryCompletionHook :: Maybe (String -> IO String) -> IO ()

setCompletionWordBreakHook :: Maybe (IO (Maybe String)) -> IO ()

setCompletionDisplayMatchesHook :: Maybe ([String] -> IO ()) -> IO ()