data-accessor 0.1.2 → 0.1.3

raw patch · 5 files changed

+124/−7 lines, 5 filesdep +arraydep +containersPVP ok

version bump matches the API change (PVP)

Dependencies added: array, containers

API changes (from Hackage documentation)

Files

• data-accessor.cabal +5/−3
• src/Data/Accessor/Basic.hs +25/−2
• src/Data/Accessor/Container.hs +38/−0
• src/Data/Accessor/Example.hs +38/−2
• src/Data/Accessor/MonadState.hs +18/−0

@@ -1,14 +1,15 @@ Name:             data-accessor-Version:          0.1.2+Version:          0.1.3 License:          GPL License-File:     LICENSE Author:           Henning Thielemann <haskell@henning-thielemann.de>, Luke Palmer <lrpalmer@gmail.com> Maintainer:       Henning Thielemann <haskell@henning-thielemann.de>-Homepage:         http://code.haskell.org/data-accessor/+Homepage:         http://www.haskell.org/haskellwiki/Record_access+Package-URL:      http://code.haskell.org/data-accessor/ Category:         Data -- Portability:      Haskell98, not quite because of MTL dependency Build-Type:       Simple-Build-Depends:    base>=1.0, mtl+Build-Depends:    base>=1.0, array, containers, mtl Synopsis:         Utilities for accessing and manipulating fields of records Description:   In Haskell 98 the name of a record field@@ -56,6 +57,7 @@ Exposed-Modules:   Data.Accessor   Data.Accessor.Basic+  Data.Accessor.Container   Data.Accessor.Show   Data.Accessor.Tuple   Data.Accessor.BinaryRead

@@ -4,6 +4,7 @@ -} module Data.Accessor.Basic (    T, fromSetGet, fromLens,+   self, null,    set, (^=), compose,    get, (^.),    modify, (^:),@@ -11,6 +12,11 @@    ($%),    ) where +import Prelude hiding (null)+++-- * Define and construct accessors+ {- | The access functions we propose, look very similar to those needed for List.mapAccumL (but parameter order is swapped) and State monad.@@ -27,8 +33,22 @@ fromLens lens =    Cons $ \ x r -> let (y,f) = lens r in (y, f x) -{- * Access helper functions similar to State methods -} +{- |+Simple accessor: Access the record itself+-}+self :: T r r+self = fromSetGet const id++{- |+Simple accessor: Access a (non-existing) element of type @()@+-}+null :: T r ()+null = fromSetGet (flip const) (const ())+++-- * Apply accessors, similar to State methods+ {- | Set the value of a field. -} set :: T r a -> a -> r -> r set f x = snd . decons f x@@ -71,7 +91,7 @@ get :: T r a -> r -> a get f = fst . decons f undefined -infixl 9 ^.+infixl 8 ^.  {- | 'get' as infix operator.@@ -106,6 +126,7 @@ ($%) = flip ($)  +-- * Accessor combinators  infixl 9 .> @@ -120,7 +141,9 @@        (cOld, bNew) = decons g cNew bOld    in  (cOld, aNew) + infixr 9 <.+ {- | Accessor composition the other direction. 

@@ -0,0 +1,38 @@+{- |+This module allows to access elements of arrays and finite maps+like elements of records.+This is especially useful for working with nested structures+consisting of arrays, maps and records.+-}+module Data.Accessor.Container+   (array, mapDefault, mapMaybe, ) where++import qualified Data.Accessor.Basic as Accessor++import qualified Data.Array as Array+import qualified Data.Map   as Map++import Prelude hiding (map)+++array :: Array.Ix i => i -> Accessor.T (Array.Array i e) e+array i = Accessor.fromSetGet (\e a -> a Array.// [(i,e)]) (Array.! i)++{- |+Treats a finite map like an infinite map,+where all undefined elements are replaced by a default value.+-}+mapDefault :: Ord key => elem -> key -> Accessor.T (Map.Map key elem) elem+mapDefault deflt key =+   Accessor.fromSetGet (Map.insert key) (Map.findWithDefault deflt key)++{- |+Treats a finite map like an infinite map,+where all undefined elements are 'Nothing'+and defined elements are 'Just'.+-}+mapMaybe :: Ord key => key -> Accessor.T (Map.Map key elem) (Maybe elem)+mapMaybe key =+   Accessor.fromSetGet+      (\e m -> maybe (Map.delete key m) (flip (Map.insert key) m) e)+      (Map.lookup key)

@@ -3,14 +3,18 @@ import Data.Accessor.Basic ((.>), ($%), (^.), (^:), (^=), ) import Data.Accessor.Tuple (first, second, ) -import qualified Data.Accessor.Basic as Accessor+import qualified Data.Accessor.Container as Container import qualified Data.Accessor.BinaryRead as Read import qualified Data.Accessor.Show as Show+import qualified Data.Accessor.Basic as Accessor +import qualified Data.Array as Array+import qualified Data.Map   as Map+ import Data.Accessor.MonadState ((%=), (%:), ) import qualified Data.Accessor.MonadState as AState import Control.Monad.State (State)-import Data.Char (ord, )+import Data.Char (ord, toUpper, )  import Prelude hiding (init) @@ -96,3 +100,35 @@  show1 :: String show1 = showsPair 5 ('d',8) ""+++self :: Char+self = Accessor.self ^: succ $ 'a'++null :: Char+null = Accessor.null ^= () $ 'a'+++array :: Array.Array Int Char+array =+   Container.array 7 ^: toUpper $+   Container.array 2 ^= 'z' $+   Array.listArray (0,9) ['a'..]++mapDefault :: Map.Map Int Char+mapDefault =+   Container.mapDefault ' ' 1 ^= '-' $+   Container.mapDefault ' ' 3 ^= 'z' $+   Container.mapDefault ' ' 5 ^: toUpper $+   Container.mapDefault ' ' 9 ^: toUpper $+   Map.fromList $ zip (map (^(2::Int)) [0..7]) ['a'..]++mapMaybe :: Map.Map Int Char+mapMaybe =+   Container.mapMaybe 1 ^= Just '-' $+   Container.mapMaybe 2 ^= Nothing $+   Container.mapMaybe 3 ^= Just 'z' $+   Container.mapMaybe 4 ^= Nothing $+   Container.mapMaybe 5 ^: fmap toUpper $+   Container.mapMaybe 9 ^: fmap toUpper $+   Map.fromList $ zip (map (^(2::Int)) [0..7]) ['a'..]

@@ -14,6 +14,24 @@ modify :: MonadState r m => Accessor.T r a -> (a -> a) -> m () modify f g = State.modify (Accessor.modify f g) +{- |+Modify a record element and return its old value.+-}+getAndModify :: MonadState r m => Accessor.T r a -> (a -> a) -> m a+getAndModify f g =+   do x <- get f+      modify f g+      return x++{- |+Modify a record element and return its new value.+-}+modifyAndGet :: MonadState r m => Accessor.T r a -> (a -> a) -> m a+modifyAndGet f g =+   do modify f g+      get f++  infix 1 %=, %: