System.IO.Continuation

This module implements continuation-based I/O as described in Haskell Report 1.2. It shares the same basic types as stream-based I/O.

Continuation Types

type SuccCont = Dialogue

type StrCont = String -> Dialogue

type StrListCont = [String] -> Dialogue

type BinCont = Bin -> Dialogue

type FailCont = IOError -> Dialogue

Transactions

Continuation-based IO is based on a collection of functions called transactions/ defined in a continuation style. Please refer to the corresponding constructors under Request for documentations.

done :: Dialogue

readFile :: Name -> FailCont -> StrCont -> Dialogue

writeFile :: Name -> String -> FailCont -> SuccCont -> Dialogue

appendFile :: Name -> String -> FailCont -> SuccCont -> Dialogue

readBinFile :: Name -> FailCont -> BinCont -> Dialogue

writeBinFile :: Name -> Bin -> FailCont -> SuccCont -> Dialogue

appendBinFile :: Name -> Bin -> FailCont -> SuccCont -> Dialogue

deleteFile :: Name -> FailCont -> SuccCont -> Dialogue

statusFile :: Name -> FailCont -> StrCont -> Dialogue

readChan :: Name -> FailCont -> StrCont -> Dialogue

appendChan :: Name -> String -> FailCont -> SuccCont -> Dialogue

readBinChan :: Name -> FailCont -> BinCont -> Dialogue

appendBinChan :: Name -> Bin -> FailCont -> SuccCont -> Dialogue

statusChan :: Name -> FailCont -> StrCont -> Dialogue

echo :: Bool -> FailCont -> SuccCont -> Dialogue

getArgs :: FailCont -> StrListCont -> Dialogue

getProgName :: FailCont -> StrCont -> Dialogue

getEnv :: String -> FailCont -> StrCont -> Dialogue

setEnv :: String -> String -> FailCont -> SuccCont -> Dialogue

Other Functions

exit :: FailCont

abort :: FailCont

print :: Show a => a -> Dialogue

prints :: Show a => a -> String -> Dialogue

interact :: (String -> String) -> Dialogue

Re-exports

Types

type Dialogue = [Response] -> [Request]

Type of a Haskell program. [Response] is an ordered list of responses and [Request] is an ordered list of requests; the nth response is the operating system's reply to the nth request.

type Bin = ByteString

Bin is a datatype for binary values, as required by the report, and is implemented as a lazy ByteString.

type Name = String

This type synonym is described in Haskell Report 1.0, and exists for backward compatibility.

data IOError

Constructors

WriteError String

ReadError String

SearchError String

FormatError String

Since we're using a modern device and the maximum line length and page length allowed on the channel have no bound, this error would never occur.

OtherError String

Instances

Read IOError

Defined in System.IO.Dialogue

Methods

readsPrec :: Int -> ReadS IOError

readList :: ReadS [IOError]

readPrec :: ReadPrec IOError

readListPrec :: ReadPrec [IOError]

Show IOError

Defined in System.IO.Dialogue

Methods

showsPrec :: Int -> IOError -> ShowS

show :: IOError -> String

showList :: [IOError] -> ShowS

Eq IOError

Defined in System.IO.Dialogue

Methods

(==) :: IOError -> IOError -> Bool

(/=) :: IOError -> IOError -> Bool

Ord IOError

Defined in System.IO.Dialogue

Methods

compare :: IOError -> IOError -> Ordering

(<) :: IOError -> IOError -> Bool

(<=) :: IOError -> IOError -> Bool

(>) :: IOError -> IOError -> Bool

(>=) :: IOError -> IOError -> Bool

max :: IOError -> IOError -> IOError

min :: IOError -> IOError -> IOError

Channels

stdin :: Name

The stdin channel. Readable.

stdout :: Name

The stdout channel. Writable.

stderr :: Name

The stderr channel. Writable.

stdecho :: Name

The stdecho channel. Writable. Attached to stdout.

Run the Program

runDialogue :: Dialogue -> IO ()

The central function to run a program.