-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | An implementation of a real-time concurrent queue
--   
--   An implementation of a real-time concurrent queue.
@package stm-queue
@version 0.1.2.2


module Data.Queue

-- | Real time <a>Queue</a> backed by transactional variables
--   (<a>TVar</a>s)
data Queue a

-- | Create a new, empty <a>Queue</a>
newQueue :: STM (Queue a)

-- | Peek at the top of the <a>Queue</a>, returning the top element.
peek :: Queue a -> STM a

-- | Try to <a>peek</a> for the top item of the <a>Queue</a>. This function
--   is offered to easily port from the <a>TQueue</a> offered in the stm
--   package, but is not the intended usage of the library.
tryPeek :: Queue a -> STM (Maybe a)

-- | Enqueue a single item onto the <a>Queue</a>.
enqueue :: Queue a -> a -> STM ()

-- | Dequeue a single item onto the <a>Queue</a>, <a>retry</a>ing if there
--   is nothing there. This is the motivating use case of this library,
--   allowing a thread to register its interest in the head of a
--   <a>Queue</a> and be woken up by the runtime system to read from the
--   top of that <a>Queue</a> when an item has been made available.
dequeue :: Queue a -> STM a

-- | Try to <a>dequeue</a> a single item. This function is offered to allow
--   users to easily port from the <a>TQueue</a> offered in the stm
--   package, but is not the intended usage of the library.
tryDequeue :: Queue a -> STM (Maybe a)

-- | Efficiently read the entire contents of a <a>Queue</a> into a list.
flush :: Queue a -> STM [a]