System.Process.Read.Chunks

The readProcessChunks function is a process reader that returns a list (stream) of Output, which represent chunks of text read from Stdout, Stderr, a Result code, or an Exception. This has the advantage of preserving the order in which these things appeared. The foldOutput, foldOutputsL, and foldOutputsR functions can be used to process the output stream. The output text can be any NonBlocking instance, which needs to be implemented using a non-blocking read function like hGetSome.

Documentation

class ListLikePlus a c => NonBlocking a c where

Class of types which can also be used by readProcessChunks.

Methods

hGetSome :: Handle -> LengthType a -> IO a

toChunks :: a -> [a]

Instances

NonBlocking ByteString Word8

NonBlocking ByteString Word8

data Output a

Constructors

Stdout a

Stderr a

Result ExitCode

Exception IOError

Instances

Eq a => Eq (Output a)

Show a => Show (Output a)

foldOutput :: ListLikePlus a c => (ExitCode -> b) -> (a -> b) -> (a -> b) -> (IOError -> b) -> Output a -> b

A fold function for the Output type, dispatches the value depending on the constructor.

foldOutputsL :: ListLikePlus a c => (b -> ExitCode -> b) -> (b -> a -> b) -> (b -> a -> b) -> (b -> IOError -> b) -> b -> [Output a] -> b

foldOutputsR :: forall a b c. ListLikePlus a c => (b -> ExitCode -> b) -> (b -> a -> b) -> (b -> a -> b) -> (b -> IOError -> b) -> b -> [Output a] -> b

readProcessChunks :: NonBlocking a c => CreateProcess -> a -> IO [Output a]

This is a process runner which (at the cost of a busy loop) gives you the chunks of text read from stdout and stderr interleaved in the order they were written, along with any ResourceVanished exxception that might occur. Its interface is similar to readModifiedProcessWith, though the implementation is somewhat alarming.

readProcessChunks' :: NonBlocking a c => CreateProcess -> a -> IO [Output a]

A test version of readProcessChunks. Pipes code here: http:hpaste.org/76631