Documentation

A type class for input types. A common interface for delivering messages.

A type class for msgBox types. A common interface for receiving messages.

Types that configure and allow the creation of a MessageBox.

Create IsMessageBox instances from a parameter. Types that determine MessageBox values.

For a limited message box this might be the limit of the message queue.

Receive a message and apply a function to it.

An input for a BlockingBox that will block for not much more than the given timeout when the message box is full.

A BlockingBox an a WaitingBoxLimit for the IsMessageBox instance.

A IsMessageBoxArg instance wrapping the BlockingBox with independently configurable timeouts for receive and deliver.

A wrapper around BlockingInput with a non-blocking IsInput instance.

deliver will enqueue the message or return False immediately, if the message box already contains more messages than it's limit allows.

A BlockingBox wrapper for non-blocking IsMessageBox instances.

The difference to the BlockingBox instance is that deliver immediately returns if the message box limit is surpassed.

A BlockingBoxLimit wrapper for non-blocking IsMessageBoxArg instances.

A message queue into which messages can be enqued by, e.g. tryToDeliver. Messages can be received from an BlockingBox.

The Input is the counter part of a BlockingBox.

A message queue out of which messages can by received.

This is the counter part of Input. Can be used for reading messages.

Messages can be received by receive or tryReceive.

Contains the (vague) limit of messages that a BlockingBox can buffer, i.e. that deliver can put into a BlockingInput of a BlockingBox.

Message Limit

The message limit must be a reasonable small positive integer that is also a power of two. This stems from the fact that Unagi is used under the hood.

The limit is a lower bound.

Convert a MessageLimit to the Int representation.

The (empty) configuration for creating UnlimitedBoxes using the IsMessageBoxArg methods.

A message queue into which messages can be enqued by, e.g. deliver. Messages can be received from an UnlimitedBox.

The UnlimitedBoxInput is the counter part of a UnlimitedBox.

A message queue out of which messages can by received.

This is the counter part of Input. Can be used for reading messages.

Messages can be received by receive or tryReceive.

A wrapper around values that are instances of IsInput.

A wrapper around values that are instances of IsMessageBox.

The Input type will be wrapped using CatchAllInput.

A wrapper around values that are instances of IsMessageBoxArg. The factory wraps the result of the delegated newMessageBox invocation into a CatchAllBox.

The result of callAsync. Use waitForReply or tryTakeReply.

Exception thrown by replyTo when replyTo is call more than once.

The failures that the receiver of a Return Command, i.e. a Blocking, can communicate to the caller, in order to indicate that processing a request did not or will not lead to the result the caller is blocked waiting for.

This is like Input, it can be used by the receiver of a Blocking to either send a reply using reply or to fail/abort the request using sendRequestError

A message valid for some user defined apiTag.

The apiTag tag (phantom-) type defines the messages allowed here, declared by the instance of Command for apiTag.

Indicates if a Command requires the receiver to send a reply or not.

This family allows to encode imperative commands.

The clauses of a Command define the commands that a process should execute.

Every clause may specify an individual ReturnType that declares if and what response is valid for a message.

For example:

type LampId = Int

data instance Command LightControl r where
  GetLamps :: Command LigthControl (Return [LampId])
  SwitchOn :: LampId -> Command LigthControl FireAndForget

data LightControl -- the phantom type

The type index of the Command family is the uninhabited LightControl type. .

The second type parameter indicates if a message requires the receiver to send a reply back to the blocked and waiting sender, or if no reply is necessary.

Enqueue a NonBlocking Message into an Input. This is just for symetry to call, this is equivalent to: input -> MessageBox.tryToDeliver input . NonBlocking

The

Enqueue a Blocking Message into an IsInput and wait for the response.

If message delivery failed, return Left CouldNotEnqueueCommand.

If no reply was given by the receiving process (using replyTo) within a given duration, return Left BlockingCommandTimedOut.

Important: The given timeout starts after deliver has returned, if deliver blocks and delays, call might take longer than the specified timeout.

The receiving process can either delegate the call using delegateCall or reply to the call by using: replyTo.

This is called from the callback contained in the Blocking Message.

When handling a Blocking Message the ReplyBox contained in the message contains the TMVar for the result, and this function puts the result into it.

Pass on the call to another process.

Used to implement dispatcher processes.

Returns True if the deliver operation was successful.

Enqueue a Blocking Message into an IsInput.

If the call to deliver fails, return Nothing otherwise Just the AsyncReply.

The receiving process must use replyTo with the ReplyBox received along side the Command in the Blocking.

Wait for the reply of a Blocking Message sent by callAsync.

If a reply for an callAsync operation is available return it, otherwise return Nothing.

Class of environment records containing a CounterVar for CallIds.

An identifier value every command send by calls.

Create a new CallId CounterVar.

Increment and get a new CallId.

A type class for MonadReader based applications.

An AtomicCounter.

A threadsafe atomic a

Atomically increment and get the value of the Counter for type a that must be present in the env.

Atomically increment and get the value of the Counter for type a that must be present in the env.

Create a new CounterVar starting at 0.

A wrapper around an IO action that returns value in the future.

Return Just the value or Nothing, when the value is not available yet.

Once the value is available, that value will be returned everytime this function is invoked.

Poll a Future until the value is present.