ListZipper (empty) → 1.0.0.0

raw patch · 4 files changed

+98/−0 lines, 4 filesdep +basesetup-changed

Dependencies added: base

Files

• Data/List/Zipper.hs +55/−0
• LICENSE +23/−0
• ListZipper.cabal +18/−0
• Setup.hs +2/−0

@@ -0,0 +1,55 @@+module Data.List.Zipper where++data Zipper a = Zip ![a] ![a]++empty :: Zipper a+empty = Zip [] []++fromList :: [a] -> Zipper a+fromList as = Zip [] as++fromListEnd :: [a] -> Zipper a+fromListEnd as = Zip (reverse as) []++toList :: Zipper a -> [a]+toList (Zip ls rs) = reverse ls ++ rs++beginp, endp, emptyp :: Zipper a -> Bool+beginp (Zip [] _ ) = True+beginp _           = False+endp   (Zip _  []) = True+endp   _           = False+emptyp (Zip [] []) = True+emptyp _           = False++-- | @cursor z@ returns the targeted element in @z@.+--+-- This function is not total, but the invariant is that+-- @endp z == False@ means that you can safely call+-- @cursor z@.+cursor :: Zipper a -> a+cursor (Zip _ (a:_)) = a++left, right :: Zipper a -> Zipper a+left  (Zip ls (a:rs)) = Zip (a:ls) rs+left  z               = z+right (Zip (a:ls) rs) = Zip ls (a:rs)+right z               = z++insert, push :: a -> Zipper a -> Zipper a+insert a (Zip ls rs) = Zip ls (a:rs)+push   a (Zip ls rs) = Zip (a:ls) rs++delete, pop :: Zipper a -> Zipper a+delete (Zip ls (_:rs)) = Zip ls rs+delete z               = z+pop    (Zip (_:ls) rs) = Zip ls rs+pop    z               = z++-- | @replace a z@ changes the current element in the zipper+-- to the passed in value.  If there is no current element,+-- the zipper is unchanged.  If you want to add the element+-- in that case instead, use @insert a (delete z)@.+replace :: a -> Zipper a -> Zipper a+replace a (Zip ls (_:rs)) = Zip ls (a:rs)+replace _ z               = z

@@ -0,0 +1,23 @@+Copyright (c) 2008, Ryan Ingram+All rights reserved.++Redistribution and use in source and binary forms, with or without+modification, are permitted provided that the following conditions are met:++1. Redistributions of source code must retain the above copyright notice,+   this list of conditions and the following disclaimer.+2. Redistributions in binary form must reproduce the above copyright+   notice, this list of conditions and the following disclaimer in the+   documentation and/or other materials provided with the distribution.++THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN+CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)+ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE+POSSIBILITY OF SUCH DAMAGE.

@@ -0,0 +1,18 @@+name:            ListZipper+version:         1.0.0.0+copyright:       (c) 2008 Ryan Ingram+license:         BSD3+license-file:    LICENSE+author:          Ryan Ingram <ryani.spam@gmail.com>+maintainer:      Ryan Ingram <ryani.spam@gmail.com>+category:        Data+synopsis:        Simple zipper for lists+description:     List zipper with O(1) get element at cursor, insert at cursor,+                 delete at cursor, move right, and move left operations.+stability:       stable+build-type:      Simple+cabal-version:   >= 1.2.1++library+  exposed-modules: Data.List.Zipper+  build-depends:   base >= 3.0

@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain