Foreign.Erlang

Speaks the Erlang network protocol and impersonates an Erlang node on the network. Fully capable of bi-directional communication with Erlang. Erlang types are, as far as reasonable, mapped to Haskell types. Messages to Erlang are just function calls in Haskell, and messages from Erlang are delivered to MVars.

Low-level communication with the Erlang Port-Mapper Daemon.

epmdGetNames :: IO [String]

Return the names and addresses of all registered Erlang nodes.

epmdGetPort :: String -> IO Int

Return the port address of a named Erlang node.

epmdGetPortR4 :: String -> IO (Int, Int, Int, Int, Int, String, String)

Returns (port, nodeType, protocol, vsnMax, vsnMin, name, extra)

type ErlRecv = IO (Maybe ErlType, Maybe ErlType)

type ErlSend = (Maybe ErlType, Maybe ErlType) -> IO ()

erlConnect :: String -> String -> IO (ErlSend, ErlRecv)

toNetwork :: Int -> Integer -> [Word8]

High-level communication.

genCall :: Erlang a => MBox -> Node -> Pid -> a -> IO ErlType

gen_server:call(Pid, Msg)

genCast :: Erlang a => MBox -> Node -> Pid -> a -> IO ()

gen_server:cast(Pid, Msg)

rpcCall :: MBox -> Node -> String -> String -> [ErlType] -> IO ErlType

rpc:call(Node, Module, Function, Arguments)

rpcCast :: MBox -> Node -> String -> String -> [ErlType] -> IO ()

rpc:cast(Node, Module, Function, Arguments)

Mnesia database methods.

backup :: MBox -> String -> String -> IO ErlType

dirtyAllKeys :: MBox -> String -> String -> IO ErlType

dirtyFirst :: MBox -> String -> String -> IO ErlType

dirtyNext :: MBox -> String -> String -> ErlType -> IO ErlType

dirtyLast :: MBox -> String -> String -> IO ErlType

dirtyPrev :: MBox -> String -> String -> ErlType -> IO ErlType

dirtyMatchObject :: MBox -> String -> ErlType -> IO ErlType

dirtyRead :: MBox -> String -> String -> ErlType -> IO ErlType

dirtySelect :: MBox -> String -> String -> ErlType -> IO ErlType

Low-level communication.

Represents a Haskell node (program).

data Self

Represents a Haskell node. There should be one of these per process.

createSelf :: String -> IO Self

Instantiate a Haskell node. This initializes the FFI.

Represents a Haskell process (thread).

data MBox

Haskell threads don't natively have Erlang process IDs. Instead, we use a mailbox abstraction that we can assign PIDs to for communication with Erlang.

createMBox :: Self -> IO MBox

Create a new process on the Haskell side. Usually corresponds to a thread but doesn't need to.

mboxRef :: MBox -> IO ErlType

Return a new unique object reference.

mboxSelf :: MBox -> ErlType

Return the PID of the given mailbox.

Represents Erlang nodes and processes.

type Node = String

The name of an Erlang node on the network.

type Pid = Either ErlType String

Represents a foreign (Erlang) process. A process can be identified either by its low-level ID (Left pid) or by its registered name (Right name).

Communication to/from Erlang.

mboxRecv :: MBox -> IO ErlType

Receive the next message addressed to this mailbox.

mboxRecv' :: MBox -> ErlType -> IO ErlType

Receive a reply message. That is, looks for the next message identified by the given reference.

mboxSend :: Erlang a => MBox -> Node -> Pid -> a -> IO ()

{Node, Pid} ! Msg.

Native Erlang data types.

Haskell representation.

data ErlType

Constructors

ErlNull

ErlInt Int

ErlBigInt Integer

ErlString String

ErlAtom String

ErlBinary [Word8]

ErlList [ErlType]

ErlTuple [ErlType]

ErlPid ErlType Int Int Int

ErlPort ErlType Int Int

ErlRef ErlType Int Int

ErlNewRef ErlType Int [Word8]

Instances

Eq ErlType

Show ErlType

Binary ErlType

Erlang ErlType

Erlang [ErlType]

Conversion between native Haskell types and ErlType.

class Erlang a where

Methods

toErlang :: a -> ErlType

fromErlang :: ErlType -> a

Instances

Erlang Bool

Erlang Int

Erlang Integer

Erlang String

Erlang ErlType

Erlang a => Erlang [a]

Erlang [ErlType]

(Erlang a, Erlang b) => Erlang (a, b)

(Erlang a, Erlang b, Erlang c) => Erlang (a, b, c)

(Erlang a, Erlang b, Erlang c, Erlang d) => Erlang (a, b, c, d)

(Erlang a, Erlang b, Erlang c, Erlang d, Erlang e) => Erlang (a, b, c, d, e)

Easy type-safe access to tuple members.

nth :: Erlang a => Int -> ErlType -> a

Internal packing functions.

getA :: Int -> Get [Char]

getC :: Get Int

getErl :: Get ErlType

getN :: Get Int

geta :: Int -> Get [Word8]

getn :: Get Int

putA :: String -> Put

putC :: Int -> Put

putErl :: ErlType -> PutM ()

putN :: Int -> Put

puta :: [Word8] -> Put

putn :: Int -> Put

tag :: Char -> Put

Miscellaneous utilities.

erlangTimeToSeconds :: Integral a => ErlType -> a

Convert a tuple (from erlang:now()) to seconds from Jan 1, 1970.

secondsToErlangTime :: Integral a => a -> ErlType

Convert seconds to an Erlang tuple representing time.