pointedlist 0.1 → 0.2

raw patch · 4 files changed

+105/−6 lines, 4 filesbuild-type:Customsetup-changed

Files

• Data/List/PointedList.hs +23/−3
• Data/List/PointedList/Circular.hs +65/−0
• Setup.hs +11/−1
• pointedlist.cabal +6/−2

@@ -2,13 +2,13 @@ --   an index position in the list (the 'focus'). module Data.List.PointedList where -import Prelude hiding (foldl, foldr)+import Prelude hiding (foldl, foldr, elem)  import Control.Applicative import Control.Monad import Data.Binary-import Data.Foldable-import Data.List hiding (foldl, foldr)+import Data.Foldable hiding (find)+import Data.List hiding (length, foldl, foldr, find, elem) import Data.Maybe import Data.Traversable @@ -144,6 +144,26 @@ -- > contextMap atStart (fromJust $ fromList [1..5]) contextMap :: (PointedList a -> b) -> PointedList a -> PointedList b contextMap f z = fmap f $ positions z++-- | Move the focus to the specified index. +move :: Int -> PointedList a -> Maybe (PointedList a)+move n pl@(PointedList a _ _) | n <     0 || n >= Data.List.PointedList.length pl+                                                       = Nothing +                              | Prelude.length a == n  = Just pl+                              | Prelude.length a >= n  = move n (tryPrevious pl)+                              | otherwise              = move n (tryNext pl)++-- | Move the focus to the specified element, if it is present.+find :: Eq a => a -> PointedList a -> Maybe (PointedList a)+find x pl@(PointedList a b c)+  | x == b     = Just pl+  | x `elem` a = find x (tryPrevious pl)+  | x `elem` c = find x (tryNext pl)+  | otherwise  = Nothing++-- | Determine the index of the focus.+index :: PointedList a -> Int+index (PointedList a _ _) = Prelude.length a  -------------------------------------------------------- -- DERIVES GENERATED CODE

@@ -0,0 +1,65 @@+module Data.List.PointedList.Circular+  ( -- Re-export many of the regular PointedList features+  module Data.List.PointedList++  -- And, of course, export the alternatives here+  , next+  , previous+  , delete+  , deleteLeft+  , deleteRight+  ) where++import Data.List.PointedList+  ( PointedList(..)+  , singleton+  , fromList+  , fromListEnd+  , focus+  , insert+  , insertLeft+  , insertRight+  , length+  , positions+  , contextMap+  , move+  , find+  , index+  )+import qualified Data.List.PointedList as PL++next :: PointedList a -> PointedList a+next pl@(PointedList [] b []) = pl+next    (PointedList a  b []) = let (x:xs) = reverse a in+                                  PointedList [] x (xs ++ [b])+next pl = PL.tryNext pl ++previous :: PointedList a -> PointedList a+previous pl@(PointedList [] b []) = pl+previous    (PointedList [] b c ) = let (x:xs) = reverse c in+                                      PointedList (xs ++ [b]) x []+previous pl = PL.tryPrevious pl++-- | An alias of 'deleteRight'.+delete :: PointedList a -> Maybe (PointedList a)+delete = deleteRight++-- | Possibly delete the element at the focus, then move the element on the+--   left to the focus. If no element is on the left, focus on the element to+--   the right. If the deletion will cause the list to be empty, return+--   @Nothing@.+deleteLeft :: PointedList a -> Maybe (PointedList a)+deleteLeft (PointedList []     _ []) = Nothing+deleteLeft (PointedList (l:ls) _ rs) = Just $ PointedList ls l rs+deleteLeft (PointedList []     _ rs) = let (x:xs) = reverse rs in+                                         Just $ PointedList xs x []++-- | Possibly delete the element at the focus, then move the element on the+--   right to the focus. If no element is on the right, focus on the element to+--   the left. If the deletion will cause the list to be empty, return+--   @Nothing@.+deleteRight :: PointedList a -> Maybe (PointedList a)+deleteRight (PointedList [] _ []    ) = Nothing+deleteRight (PointedList ls _ (r:rs)) = Just $ PointedList ls r rs+deleteRight (PointedList ls _ []    ) = let (x:xs) = reverse ls in+                                            Just $ PointedList [] x xs

@@ -1,5 +1,15 @@ #!/usr/bin/env runhaskell+import Distribution.PackageDescription import Distribution.Simple+import Distribution.Simple.LocalBuildInfo +-- Import the local test suite+import Tests.PL (test)++runTest :: Args -> Bool -> PackageDescription -> LocalBuildInfo -> IO ()+runTest _ _ _descr _buildInfo = test+ main :: IO ()-main = defaultMain+main = defaultMainWithHooks $ simpleUserHooks {+    runTests = runTest+  }

@@ -1,16 +1,20 @@ Name:          pointedlist-Version:       0.1+Version:       0.2 Synopsis:      A zipper-like comonad which works as a list, tracking a position. Category:      Data Description:     A PointedList tracks the position in a non-empty list which works similarly     to a zipper. A current item is always required, and therefore the list may     never be empty.++    A circular PointedList wraps around to the other end when progressing past+    the actual edge. License:       BSD3 License-file:  LICENSE Author:        Jeff Wheeler Maintainer:    jeffwheeler@gmail.com-Build-type:    Simple+Build-type:    Custom Build-depends: base>=4 Build-depends: binary Exposed-modules: Data.List.PointedList+                 Data.List.PointedList.Circular