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diff --git a/tests/Diff.hs b/tests/Diff.hs deleted file mode 100644 index f7e562ee2..000000000 --- a/tests/Diff.hs +++ /dev/null @@ -1,76 +0,0 @@ ------------------------------------------------------------------------------ --- | --- Module : Data.Algorithm.Diff --- Copyright : (c) Sterling Clover 2008 --- License : BSD 3 Clause --- Maintainer : s.clover@gmail.com --- Stability : experimental --- Portability : portable --- --- This is an implementation of the O(ND) diff algorithm as described in --- \"An O(ND) Difference Algorithm and Its Variations (1986)\" --- <http://citeseer.ist.psu.edu/myers86ond.html>. It is O(mn) in space. --- The algorithm is the same one used by standared Unix diff. --- The assumption is that users of this library will want to diff over --- interesting things or peform interesting tasks with the results --- (given that, otherwise, they would simply use the standard Unix diff --- utility). Thus no attempt is made to present a fancier API to aid --- in doing standard and uninteresting things with the results. ------------------------------------------------------------------------------ - -module Diff (DI(..), getDiff, getGroupedDiff) where -import Data.Array -import Data.List - --- | Difference Indicator. A value is either from the First list, the Second --- or from Both. -data DI = F | S | B deriving (Show, Eq) - -data DL = DL {poi::Int, poj::Int, path::[DI]} deriving (Show, Eq) - -instance Ord DL where x <= y = poi x <= poi y - -canDiag :: (Eq a) => [a] -> [a] -> Int -> Int -> (Int, Int) -> Bool -canDiag as bs lena lenb = \(i,j) -> - if i < lena && j < lenb then arAs ! i == arBs ! j else False - where arAs = listArray (0,lena - 1) as - arBs = listArray (0,lenb - 1) bs - -chunk :: Int -> [a] -> [[a]] -chunk x = unfoldr (\a -> case splitAt x a of ([],[]) -> Nothing; a' -> Just a') - -dstep :: ((Int,Int)->Bool) -> [DL] -> [DL] -dstep cd dls = map maximum $ [hd]:(chunk 2 rst) - where (hd:rst) = concatMap extend dls - extend dl = let pdl = path dl - in [addsnake cd $ dl {poi=poi dl + 1, path=(F : pdl)}, - addsnake cd $ dl {poj=poj dl + 1, path=(S : pdl)}] - -addsnake :: ((Int,Int)->Bool) -> DL -> DL -addsnake cd dl - | cd (pi, pj) = addsnake cd $ - dl {poi = pi + 1, poj = pj + 1, path=(B : path dl)} - | otherwise = dl - where pi = poi dl; pj = poj dl - -lcs :: (Eq a) => [a] -> [a] -> [DI] -lcs as bs = path . head . dropWhile (\dl -> poi dl /= lena || poj dl /= lenb) . - concat . iterate (dstep cd) . (:[]) . addsnake cd $ - DL {poi=0,poj=0,path=[]} - where cd = canDiag as bs lena lenb - lena = length as; lenb = length bs - --- | Takes two lists and returns a list indicating the differences --- between them. -getDiff :: (Eq t) => [t] -> [t] -> [(DI, t)] -getDiff a b = markup a b . reverse $ lcs a b - where markup (x:xs) ys (F:ds) = (F, x) : markup xs ys ds - markup xs (y:ys) (S:ds) = (S, y) : markup xs ys ds - markup (x:xs) (_:ys) (B:ds) = (B, x) : markup xs ys ds - markup _ _ _ = [] - --- | Takes two lists and returns a list indicating the differences --- between them, grouped into chunks. -getGroupedDiff :: (Eq t) => [t] -> [t] -> [(DI, [t])] -getGroupedDiff a b = map go . groupBy (\x y -> fst x == fst y) $ getDiff a b - where go ((d,x) : xs) = (d, x : map snd xs) |