0 | 1 | 2 | ... | i | ... | N - 1 | ^ ^ | | back front

Create a new empty TMDeque.

IO variant of newTMDeque, which is faster without STM transaction overhead.

Push an element to the front of the deque. Silently ignored if the deque is closed.

Pop an element from the front. Blocks if the deque is open and empty. Returns Nothing when the deque is closed and empty (back-of-stream).

Pop an element from the back. Blocks if the deque is open and empty. Returns Nothing when the deque is closed and empty (back-of-stream).

Non-blocking pop from the front.

• Nothing — closed (end-of-stream)
• Just Nothing — open and empty (would block)
• Just (Just a) — got an element

Non-blocking pop from the back.

• Nothing — closed (end-of-stream)
• Just Nothing — open and empty (would block)
• Just (Just a) — got an element

Close the deque. After this, all push operations will be ignored, and all pop operations will return Nothing once the deque is empty.

Check if the deque is closed.

IO variant of isClosedTMDeque.

Check if the deque is empty. Note that an open deque may become non-empty after this returns.

IO variant of countTMDeque.