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


-- | Sequence optimized for monoidal construction and folding
--   
--   Data structure intended for accumulating a sequence of elements for
--   later traversal or folding. Useful for implementing all kinds of
--   builders on top.
--   
--   The benchmarks show that for the described use-case it is on average 2
--   times faster than <a>DList</a> and <a>Seq</a>, is on par with list
--   when you always prepend elements and is exponentially faster than list
--   when you append.
@package acc
@version 0.2

module Acc.NeAcc

-- | Non-empty accumulator.
--   
--   Relates to <a>Acc</a> the same way as <a>NonEmpty</a> to list.
data NeAcc a

module Acc

-- | Data structure intended for accumulating a sequence of elements for
--   later traversal or folding. Useful for implementing all kinds of
--   builders on top.
--   
--   Appending and prepending is always &lt;math&gt;.
--   
--   To produce a single element <a>Acc</a> use <a>pure</a>. To produce a
--   multielement <a>Acc</a> use <a>fromList</a>. To combine use
--   <a>&lt;|&gt;</a> or <a>&lt;&gt;</a> and other <a>Alternative</a> and
--   <a>Monoid</a>-related utils. To extract elements use <a>Foldable</a>
--   API.
--   
--   The benchmarks show that for the described use-case this
--   data-structure is on average 2 times faster than <a>DList</a> and
--   <a>Seq</a>, is on par with list when you always prepend elements and
--   is exponentially faster than list when you append.
--   
--   Internally it is implemented as a simple binary tree with all
--   functions optimized to use tail recursion, ensuring that you don't get
--   stack overflow.
data Acc a

-- | Prepend an element.
cons :: a -> Acc a -> Acc a

-- | Append an element.
snoc :: a -> Acc a -> Acc a

-- | Extract the first element.
--   
--   The produced accumulator will lack the extracted element and will have
--   the underlying tree rebalanced towards the beginning. This means that
--   calling <a>uncons</a> on it will be &lt;math&gt; and <a>unsnoc</a>
--   will be &lt;math&gt;.
uncons :: Acc a -> Maybe (a, Acc a)

-- | Convert to non empty list if it's not empty.
toNonEmpty :: Acc a -> Maybe (NonEmpty a)

-- | Convert to non empty acc if it's not empty.
toNeAcc :: Acc a -> Maybe (NeAcc a)

-- | Enumerate in range, inclusively.
enumFromTo :: (Enum a, Ord a) => a -> a -> Acc a
instance GHC.Base.Functor Acc.Acc
instance Control.DeepSeq.NFData a => Control.DeepSeq.NFData (Acc.Acc a)
instance Control.DeepSeq.NFData1 Acc.Acc
instance Data.Foldable.Foldable Acc.Acc
instance Data.Traversable.Traversable Acc.Acc
instance GHC.Base.Applicative Acc.Acc
instance GHC.Base.Alternative Acc.Acc
instance GHC.Base.Semigroup (Acc.Acc a)
instance GHC.Base.Monoid (Acc.Acc a)
instance GHC.Exts.IsList (Acc.Acc a)
instance GHC.Show.Show a => GHC.Show.Show (Acc.Acc a)