Haste.Concurrent

Concurrency for Haste. Includes MVars, forking, Ajax and more.

Documentation

data Recv

data Send

type Inbox = MBox Recv

type Outbox = MBox Send

data MBox t a

An MBox is a read/write-only MVar, depending on its first type parameter. Used to communicate with server processes.

receive :: MonadConc m => Inbox a -> m a

Block until a message arrives in a mailbox, then return it.

spawn :: MonadConc m => (Inbox a -> m ()) -> m (Outbox a)

Creates a generic process and returns a MBox which may be used to pass messages to it. While it is possible for a process created using spawn to transmit its inbox to someone else, this is a very bad idea; don't do it.

statefully :: MonadConc m => st -> (st -> evt -> m (Maybe st)) -> m (Outbox evt)

Creates a generic stateful process. This process is a function taking a state and an event argument, returning an updated state or Nothing. statefully creates a MBox that is used to pass events to the process. Whenever a value is written to this MBox, that value is passed to the process function together with the function's current state. If the process function returns Nothing, the process terminates. If it returns a new state, the process again blocks on the event MBox, and will use the new state to any future calls to the server function.

(!) :: MonadConc m => Outbox a -> a -> m ()

Write a value to a MBox. Named after the Erlang message sending operator, as both are intended for passing messages to processes. This operation does not block until the message is delivered, but returns immediately.

(<!) :: MonadConc m => Outbox a -> m a -> m ()

Perform a Client computation, then write its return value to the given pipe. Mnemonic: the operator is a combination of <- and !. Just like (!), this operation is non-blocking.

wait :: Int -> CIO ()

Wait for n milliseconds.