fmlist 0.3 → 0.4

raw patch · 2 files changed

+55/−11 lines, 2 filesPVP ok

version bump matches the API change (PVP)

API changes (from Hackage documentation)

Files

• Data/FMList.hs +54/−10
• fmlist.cabal +1/−1

@@ -11,23 +11,25 @@ -- FoldMap lists: lists represented by their foldMap function. -- ------------------------------------------------------------------------------{-# LANGUAGE Rank2Types #-}+{-# LANGUAGE RankNTypes #-}  module Data.FMList (       FMList(..)+  , transform     +  -- * Construction     , empty   , singleton   , cons   , snoc   , append-  , flatten      , toList   , fromList   , fromFoldable   +  -- * Basic functions   , null   , length   , genericLength@@ -38,6 +40,8 @@   , init   , reverse   +  -- * Folding+  , flatten   , filter   , take   , drop@@ -47,6 +51,7 @@   , zip   , zipWith   +  -- * Unfolding   , iterate   , repeat   , unfoldr@@ -68,8 +73,48 @@ import Control.Monad import Control.Applicative ++-- | FMList is a foldMap function wrapped up in a newtype.+-- Examples:+--+-- > -- A right-infinite list+-- > c = 1 `cons` c+--+-- > -- A left-infinite list+-- > d = d `snoc` 2+--+-- > -- A middle-infinite list ??+-- > e = c `append` d+--+-- > *> head e+-- > 1+-- > *> last e+-- > 2+--  newtype FMList a = FM { unFM :: forall b . Monoid b => (a -> b) -> b } +-- | Transform transforms a list by changing the map function that is passed to foldMap.+-- It has the following property:+--+-- @transform a . transform b = transform (b . a)@+--+-- For example:+--+--  * @  m >>= g@+--+--  * @= flatten (fmap g m)@+--+--  * @= flatten . fmap g $ m@+--+--  * @= transform foldMap . transform (. g) $ m@+--+--  * @= transform ((. g) . foldMap) m@+--+--  * @= transform (\\f -> foldMap f . g) m@+-- +transform :: (forall b. Monoid b => (a -> b) -> (c -> b)) -> FMList c -> FMList a+transform t l = FM $ \f -> unFM l (t f)+ -- nil is exported as empty from Applicative nil          :: FMList a nil          = FM $ \_ -> mempty@@ -87,11 +132,7 @@ -- append l r  = FM $ \f -> unFM l f `mappend` unFM r f append l r   = FM $ unFM l `mappend` unFM r -flatten      :: FMList (FMList a) -> FMList a--- flatten l    = FM $ \f -> unFM l (foldMap f)-flatten l    = FM $ unFM l . foldMap - fromList     :: [a] -> FMList a fromList     = fromFoldable @@ -125,8 +166,11 @@ reverse l    = FM $ \f -> getDual $ unFM l (Dual . f)  +flatten      :: FMList (FMList a) -> FMList a+flatten      = transform foldMap+ filter       :: (a -> Bool) -> FMList a -> FMList a-filter p l   = FM $ \f -> unFM l $ \e -> if p e then f e else mempty+filter p     = transform (\f e -> if p e then f e else mempty)  take         :: (Ord n, Num n) => n -> FMList a -> FMList a take n l     = FM $ \f -> @@ -172,7 +216,7 @@   instance Functor FMList where-  fmap g c   = FM $ \f -> unFM c (f . g)+  fmap g     = transform (. g)    instance Foldable FMList where   foldMap    = flip unFM@@ -182,11 +226,11 @@  instance Monad FMList where   return     = singleton-  m >>= g    = FM $ \f -> unFM m (foldMap f . g)+  m >>= g    = transform (\f -> foldMap f . g) m  instance Applicative FMList where   pure       = return-  gs <*> xs  = FM $ \f -> unFM gs (\g -> unFM xs (f . g))+  gs <*> xs  = transform (\f g -> unFM xs (f . g)) gs      instance Monoid (FMList a) where   mempty     = nil

@@ -1,5 +1,5 @@ name:                fmlist-version:             0.3+version:             0.4 synopsis:            FoldMap lists description:            FoldMap lists are lists represented by their foldMap function.