New patches: [Add 'subsequences' and 'permutations' to Data.List Twan van Laarhoven **20071218154950] { hunk ./Data/List.hs 40 + + , subsequences -- :: [a] -> [[a]] + , permutations -- :: [a] -> [[a]] hunk ./Data/List.hs 736 + +-- | The 'subsequences' function returns the list of all subsequences of the argument. +-- +-- > subsequences "abc" == ["","c","b","bc","a","ac","ab","abc"] +subsequences :: [a] -> [[a]] +subsequences [] = [[]] +subsequences (x:xs) = subsequences xs ++ map (x:) (subsequences xs) + +-- | The 'permutations' function returns the list of all permutations of the argument. +-- +-- > permutations "abc" == ["abc","bac","bca","acb","cab","cba"] +permutations :: [a] -> [[a]] +permutations [] = [[]] +permutations (x:xs) = [zs | ys <- permutations xs, zs <- interleave x ys ] + where interleave :: a -> [a] -> [[a]] + interleave x [] = [[x]] + interleave x (y:ys) = [x:y:ys] ++ map (y:) (interleave x ys) + } ['subsequences' is now more lazy and also faster Twan van Laarhoven **20080102231629] { hunk ./Data/List.hs 739 --- > subsequences "abc" == ["","c","b","bc","a","ac","ab","abc"] +-- > subsequences "abc" == ["","a","b","ab","c","ac","bc","abc"] hunk ./Data/List.hs 741 -subsequences [] = [[]] -subsequences (x:xs) = subsequences xs ++ map (x:) (subsequences xs) +subsequences xs = [] : nonEmptySubsequences xs + +-- | The 'nonEmptySubsequences' function returns the list of all subsequences of the argument, +-- except for the empty list. +-- +-- > nonEmptySubsequences "abc" == ["a","b","ab","c","ac","bc","abc"] +nonEmptySubsequences :: [a] -> [[a]] +nonEmptySubsequences [] = [] +nonEmptySubsequences (x:xs) = [x] : foldr f [] (nonEmptySubsequences xs) + where f ys r = ys : (x : ys) : r + } ['permutations' is now more lazy and also faster Twan van Laarhoven **20080102231712] { hunk ./Data/List.hs 755 --- > permutations "abc" == ["abc","bac","bca","acb","cab","cba"] +-- > permutations "abc" == ["abc","bac","cba","bca","cab","acb"] hunk ./Data/List.hs 757 -permutations [] = [[]] -permutations (x:xs) = [zs | ys <- permutations xs, zs <- interleave x ys ] - where interleave :: a -> [a] -> [[a]] - interleave x [] = [[x]] - interleave x (y:ys) = [x:y:ys] ++ map (y:) (interleave x ys) +permutations xs = xs : perms xs [] + where + perms [] is = [] + perms (t:ts) is = foldr interleave (perms ts (t:is)) (permutations is) + where interleave xs r = let (_,zs) = interleave' id xs r in zs + interleave' f [] r = (ts, r) + interleave' f (y:ys) r = let (us,zs) = interleave' (f . (y:)) ys r + in (y:us, f (t:y:us) : zs) } Context: [Add GHC.Prim to exposedModules in the Haddock 0.x hook David Waern *-20071209173931 Please merge to the stable branch ] [Add GHC.Prim to exposedModules in the Haddock 0.x hook David Waern **20071209173931 Please merge to the stable branch ] [Simplify the GHC.Prim hack in base.cabal/Setup.hs Ian Lynagh **20071202215758] [Implement 'openTempFile' for nhc98. Malcolm.Wallace@cs.york.ac.uk**20071207133335] [docs: describe the changes to forkIO, and document forkOnIO Simon Marlow **20071205091423] [doc only: use realToFrac instead of fromRational.toRational Simon Marlow **20071205091334] [Add singletonP to GHC.PArr Roman Leshchinskiy **20071205220859] [FIX #1621: bug in Windows code for getCPUTime Simon Marlow **20071205120118 We were reading the components of FILETIME as CLong, when they should be unsigned. Word32 seems to be the correct type here. ] [protect console handler against concurrent access (#1922) Simon Marlow **20071204153940] [protect against concurrent access to the signal handlers (#1922) Simon Marlow **20071204110817] [restore fdToHandle' to avoid breaking clients (#1109) Simon Marlow **20071130135122 ] [note about how to convert CTime (aka EpochTime) to UTCTime Simon Marlow **20071130101648] [Fix some URLs Ian Lynagh **20071126214213] [Fix some links in haddock docs Ian Lynagh **20071126184428] [Don't try to make haddock links to the mtl package as we don't depend on it Ian Lynagh **20071126170631] [Escape some special characters in haddock docs Ian Lynagh **20071126163443] [FIX BUILD: maybeUpdateFile: ignore failures when removing the target Simon Marlow **20071123092219] [FIX #1753 Simon Marlow **20071122094207 hClose should close the Handle and unlock the file even if calling close() fails for some reason. ] [remove lockFile.h from install-includes Simon Marlow **20071121102248] [oops, we forgot to export traceShow Simon Marlow **20071121094300] [Fix compilation with GHC 6.2.x Simon Marlow **20071121084341] [Move file locking into the RTS, fixing #629, #1109 Simon Marlow **20071120121053 File locking (of the Haskell 98 variety) was previously done using a static table with linear search, which had two problems: the array had a fixed size and was sometimes too small (#1109), and performance of lockFile/unlockFile was suboptimal due to the linear search. Also the algorithm failed to count readers as required by Haskell 98 (#629). Now it's done using a hash table (provided by the RTS). Furthermore I avoided the extra fstat() for every open file by passing the dev_t and ino_t into lockFile. This and the improvements to the locking algorithm result in a healthy 20% or so performance increase for opening/closing files (see openFile008 test). ] [Only overwrite GHC/Prim.hs and GHC/Primopwrappers.hs if they change Simon Marlow **20071120102042 This avoids make doing unnecessary work after 'setup makefile'. ] [fix comment Simon Marlow **20071116091227] [Fix ` characters in elem's haddock docs Ian Lynagh **20071110173052] [Filter out GHC.Prim also for the Haddock step David Waern **20071109000806 Please merge to the GHC 6.8.2 branch ] [Add module of special magic GHC desugaring helper functions Simon Marlow **20071102160054 Currently containing only one such helper: (>>>) for arrow desugaring ] [add Control.Category to the nhc98 build Malcolm.Wallace@cs.york.ac.uk**20071030120459] [fix nhc98 build: need a qualified Prelude import Malcolm.Wallace@cs.york.ac.uk**20071030120410] [Fix performance regression: re-instate -funbox-strict-fields Simon Marlow **20071029150730 Yikes! While investigating the increase in code size with GHC 6.8 relative to 6.6, I noticed that in the transition to Cabal for the libraries we lost -funbox-strict-fields, which is more or less depended on by the IO library for performance. I'm astonished that we didn't notice this earlier! To reduce the chances of this happening again, I put -funbox-strict-fields in the OPTIONS_GHC pragma of the modules that need it. {-# UNPACK #-} pragmas would be better, though. ] [FIX BUILD: Haddock 1.x fails to parse (Prelude..) Simon Marlow **20071029131921] [new Control.Category, ghc ticket #1773 Ashley Yakeley **20071029022526] [new Control.Compositor module Ashley Yakeley **20071013074851 The Compositor class is a superclass of Arrow. ] [Fix doc building with Haddock 0.9 Simon Marlow **20071024090947 I was using a recent build here, which is more tolerant. ] [FIX #1258: document that openTempFile is secure(ish) Simon Marlow **20071023130928 Also change the mode from 0666 to 0600, which seems like a more sensible value and matches what C's mkstemp() does. ] [Clean up .cabal file a bit Duncan Coutts **20071022132708 specify build-type and cabal-version >= 1.2 put extra-tmp-files in the right place use os(windows) rather than os(mingw32) ] [base in 6.8 and head branch should be version 3.0 Don Stewart **20071007150408] [FIX #1652: openTempFile should accept an empty string for the directory Simon Marlow **20071018122345] [clean up duplicate code Simon Marlow **20071017141311] [expose the value of +RTS -N as GHC.Conc.numCapabilities (see #1733) Simon Marlow **20071009132042] [typo Simon Marlow **20070917130703] [put extra-tmp-files field in the right place Simon Marlow **20070914140812] [Add more entries to boring file Ian Lynagh **20070913210500] [Add a boring file Ian Lynagh **20070913204641] [TAG 2007-09-13 Ian Lynagh **20070913215720] Patch bundle hash: 82be995391c361eec90d41721bbddcec4c8cce60