isEqual, eqListBy,
thenCmp, cmpList,
removeSpaces,
+
+ -- * Edit distance
+ fuzzyMatch,
-- * Transitive closures
transitiveClosure,
escapeSpaces,
parseSearchPath,
Direction(..), reslash,
+
+ -- * Utils for defining Data instances
+ abstractConstr, abstractDataType, mkNoRepType
) where
#include "HsVersions.h"
+import Exception
import Panic
+import Data.Data
import Data.IORef ( IORef, newIORef, atomicModifyIORef )
import System.IO.Unsafe ( unsafePerformIO )
import Data.List hiding (group)
import Control.Concurrent.MVar ( MVar, newMVar, newEmptyMVar )
#ifdef DEBUG
-import qualified Data.List as List ( elem, notElem )
import FastTypes
#endif
import Control.Monad ( unless )
-import System.IO.Error as IO ( catch, isDoesNotExistError )
+import System.IO.Error as IO ( isDoesNotExistError )
import System.Directory ( doesDirectoryExist, createDirectory,
getModificationTime )
import System.FilePath
+import System.Time ( ClockTime )
+
import Data.Char ( isUpper, isAlphaNum, isSpace, ord, isDigit )
import Data.Ratio ( (%) )
-import System.Time ( ClockTime )
+import Data.Ord ( comparing )
+import Data.Bits
+import Data.Word
+import qualified Data.IntMap as IM
infixr 9 `thenCmp`
\end{code}
%************************************************************************
%* *
+\subsection{Edit distance}
+%* *
+%************************************************************************
+
+\begin{code}
+-- | Find the "restricted" Damerau-Levenshtein edit distance between two strings. See: <http://en.wikipedia.org/wiki/Damerau-Levenshtein_distance>.
+-- Based on the algorithm presented in "A Bit-Vector Algorithm for Computing Levenshtein and Damerau Edit Distances" in PSC'02 (Heikki Hyyro).
+-- See http://www.cs.uta.fi/~helmu/pubs/psc02.pdf and http://www.cs.uta.fi/~helmu/pubs/PSCerr.html for an explanation
+restrictedDamerauLevenshteinDistance :: String -> String -> Int
+restrictedDamerauLevenshteinDistance str1 str2 = restrictedDamerauLevenshteinDistanceWithLengths m n str1 str2
+ where
+ m = length str1
+ n = length str2
+
+restrictedDamerauLevenshteinDistanceWithLengths :: Int -> Int -> String -> String -> Int
+restrictedDamerauLevenshteinDistanceWithLengths m n str1 str2
+ | m <= n = if n <= 32 -- n must be larger so this check is sufficient
+ then restrictedDamerauLevenshteinDistance' (undefined :: Word32) m n str1 str2
+ else restrictedDamerauLevenshteinDistance' (undefined :: Integer) m n str1 str2
+ | otherwise = if m <= 32 -- m must be larger so this check is sufficient
+ then restrictedDamerauLevenshteinDistance' (undefined :: Word32) n m str2 str1
+ else restrictedDamerauLevenshteinDistance' (undefined :: Integer) n m str2 str1
+
+restrictedDamerauLevenshteinDistance' :: (Bits bv) => bv -> Int -> Int -> String -> String -> Int
+restrictedDamerauLevenshteinDistance' _bv_dummy m n str1 str2
+ | [] <- str1 = n
+ | otherwise = extractAnswer $ foldl' (restrictedDamerauLevenshteinDistanceWorker (matchVectors str1) top_bit_mask vector_mask) (0, 0, m_ones, 0, m) str2
+ where m_ones@vector_mask = (2 ^ m) - 1
+ top_bit_mask = (1 `shiftL` (m - 1)) `asTypeOf` _bv_dummy
+ extractAnswer (_, _, _, _, distance) = distance
+
+restrictedDamerauLevenshteinDistanceWorker :: (Bits bv) => IM.IntMap bv -> bv -> bv -> (bv, bv, bv, bv, Int) -> Char -> (bv, bv, bv, bv, Int)
+restrictedDamerauLevenshteinDistanceWorker str1_mvs top_bit_mask vector_mask (pm, d0, vp, vn, distance) char2
+ = seq str1_mvs $ seq top_bit_mask $ seq vector_mask $ seq pm' $ seq d0' $ seq vp' $ seq vn' $ seq distance'' $ seq char2 $ (pm', d0', vp', vn', distance'')
+ where
+ pm' = IM.findWithDefault 0 (ord char2) str1_mvs
+
+ d0' = ((((sizedComplement vector_mask d0) .&. pm') `shiftL` 1) .&. pm) -- No need to mask the shiftL because of the restricted range of pm
+ .|. ((((pm' .&. vp) + vp) .&. vector_mask) `xor` vp) .|. pm' .|. vn
+ hp' = vn .|. sizedComplement vector_mask (d0' .|. vp)
+ hn' = d0' .&. vp
+
+ hp'_shift = ((hp' `shiftL` 1) .|. 1) .&. vector_mask
+ hn'_shift = (hn' `shiftL` 1) .&. vector_mask
+ vp' = hn'_shift .|. sizedComplement vector_mask (d0' .|. hp'_shift)
+ vn' = d0' .&. hp'_shift
+
+ distance' = if hp' .&. top_bit_mask /= 0 then distance + 1 else distance
+ distance'' = if hn' .&. top_bit_mask /= 0 then distance' - 1 else distance'
+
+sizedComplement :: Bits bv => bv -> bv -> bv
+sizedComplement vector_mask vect = vector_mask `xor` vect
+
+matchVectors :: Bits bv => String -> IM.IntMap bv
+matchVectors = snd . foldl' go (0 :: Int, IM.empty)
+ where
+ go (ix, im) char = let ix' = ix + 1
+ im' = IM.insertWith (.|.) (ord char) (2 ^ ix) im
+ in seq ix' $ seq im' $ (ix', im')
+
+#ifdef __GLASGOW_HASKELL__
+{-# SPECIALIZE INLINE restrictedDamerauLevenshteinDistance' :: Word32 -> Int -> Int -> String -> String -> Int #-}
+{-# SPECIALIZE INLINE restrictedDamerauLevenshteinDistance' :: Integer -> Int -> Int -> String -> String -> Int #-}
+
+{-# SPECIALIZE restrictedDamerauLevenshteinDistanceWorker :: IM.IntMap Word32 -> Word32 -> Word32 -> (Word32, Word32, Word32, Word32, Int) -> Char -> (Word32, Word32, Word32, Word32, Int) #-}
+{-# SPECIALIZE restrictedDamerauLevenshteinDistanceWorker :: IM.IntMap Integer -> Integer -> Integer -> (Integer, Integer, Integer, Integer, Int) -> Char -> (Integer, Integer, Integer, Integer, Int) #-}
+
+{-# SPECIALIZE INLINE sizedComplement :: Word32 -> Word32 -> Word32 #-}
+{-# SPECIALIZE INLINE sizedComplement :: Integer -> Integer -> Integer #-}
+
+{-# SPECIALIZE matchVectors :: String -> IM.IntMap Word32 #-}
+{-# SPECIALIZE matchVectors :: String -> IM.IntMap Integer #-}
+#endif
+
+-- | Search for possible matches to the users input in the given list, returning a small number of ranked results
+fuzzyMatch :: String -> [String] -> [String]
+fuzzyMatch user_entered possibilites = map fst $ take mAX_RESULTS $ sortBy (comparing snd)
+ [ (poss, distance) | poss <- possibilites
+ , let distance = restrictedDamerauLevenshteinDistance poss user_entered
+ , distance <= fuzzy_threshold ]
+ where -- Work out an approriate match threshold (about a quarter of the # of characters the user entered)
+ fuzzy_threshold = max (round $ fromInteger (genericLength user_entered) / (4 :: Rational)) 1
+ mAX_RESULTS = 3
+\end{code}
+
+%************************************************************************
+%* *
\subsection[Utils-pairs]{Pairs}
%* *
%************************************************************************
looksLikeModuleName (c:cs) = isUpper c && go cs
where go [] = True
go ('.':cs) = looksLikeModuleName cs
- go (c:cs) = (isAlphaNum c || c == '_') && go cs
+ go (c:cs) = (isAlphaNum c || c == '_' || c == '\'') && go cs
\end{code}
Akin to @Prelude.words@, but acts like the Bourne shell, treating
modificationTimeIfExists :: FilePath -> IO (Maybe ClockTime)
modificationTimeIfExists f = do
(do t <- getModificationTime f; return (Just t))
- `IO.catch` \e -> if isDoesNotExistError e
- then return Nothing
- else ioError e
+ `catchIO` \e -> if isDoesNotExistError e
+ then return Nothing
+ else ioError e
-- split a string at the last character where 'pred' is True,
-- returning a pair of strings. The first component holds the string
Backwards -> '\\'
\end{code}
+%************************************************************************
+%* *
+\subsection[Utils-Data]{Utils for defining Data instances}
+%* *
+%************************************************************************
+
+These functions helps us to define Data instances for abstract types.
+
+\begin{code}
+abstractConstr :: String -> Constr
+abstractConstr n = mkConstr (abstractDataType n) ("{abstract:"++n++"}") [] Prefix
+\end{code}
+
+\begin{code}
+abstractDataType :: String -> DataType
+abstractDataType n = mkDataType n [abstractConstr n]
+\end{code}
+
projects / ghc-hetmet.git / blobdiff