The TMQueue type

TMQueue is an abstract type representing a closeable FIFO queue.

Build and returns a new instance of TMQueue.

IO version of newTMQueue. This is useful for creating top-level TMQueues using unsafePerformIO, because using atomically inside unsafePerformIO isn't possible.

Read the next value from the TMQueue, retrying if the queue is empty (and not closed). We return Nothing immediately if the queue is closed and empty.

A version of readTMQueue which does not retry. Instead it returns Just Nothing if the queue is open but no value is available; it still returns Nothing if the queue is closed and empty.

Get the next value from the TMQueue without removing it, retrying if the queue is empty.

A version of peekTMQueue which does not retry. Instead it returns Just Nothing if the queue is open but no value is available; it still returns Nothing if the queue is closed and empty.

Write a value to a TMQueue. If the queue is closed then the value is silently discarded. Use isClosedTMQueue to determine if the queue is closed before writing, as needed.

Put a data item back onto a queue, where it will be the next item read. If the queue is closed then the value is silently discarded; you can use peekTMQueue to circumvent this in certain circumstances.

Closes the TMQueue, preventing any further writes.

Returns True if the supplied TMQueue has been closed.

Returns True if the supplied TMQueue is empty.