-- | Highly random utility functions
module Util (
-- * Flags dependent on the compiler build
- ghciSupported, debugIsOn, ghciTablesNextToCode, picIsOn,
+ ghciSupported, debugIsOn, ghciTablesNextToCode, isDynamicGhcLib,
isWindowsHost, isWindowsTarget, isDarwinTarget,
-- * General list processing
isIn, isn'tIn,
+ -- * Tuples
+ fstOf3, sndOf3, thirdOf3,
+
-- * List operations controlled by another list
takeList, dropList, splitAtList, split,
dropTail,
isEqual, eqListBy,
thenCmp, cmpList,
removeSpaces,
+
+ -- * Edit distance
+ fuzzyMatch, fuzzyLookup,
-- * Transitive closures
transitiveClosure,
-- * Floating point
readRational,
+ -- * read helpers
+ maybeReadFuzzy,
+
-- * IO-ish utilities
createDirectoryHierarchy,
doesDirNameExist,
escapeSpaces,
parseSearchPath,
Direction(..), reslash,
+
+ -- * Utils for defining Data instances
+ abstractConstr, abstractDataType, mkNoRepType,
+
+ -- * Utils for printing C code
+ charToC
) 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 Data.Char ( isUpper, isAlphaNum, isSpace, ord, isDigit )
-import Data.Ratio ( (%) )
import System.Time ( ClockTime )
+import Data.Char ( isUpper, isAlphaNum, isSpace, chr, ord, isDigit )
+import Data.Ratio ( (%) )
+import Data.Ord ( comparing )
+import Data.Bits
+import Data.Word
+import qualified Data.IntMap as IM
+
infixr 9 `thenCmp`
\end{code}
ghciTablesNextToCode = False
#endif
-picIsOn :: Bool
-#ifdef __PIC__
-picIsOn = True
+isDynamicGhcLib :: Bool
+#ifdef DYNAMIC
+isDynamicGhcLib = True
#else
-picIsOn = False
+isDynamicGhcLib = False
#endif
isWindowsHost :: Bool
nTimes n f = f . nTimes (n-1) f
\end{code}
+\begin{code}
+fstOf3 :: (a,b,c) -> a
+sndOf3 :: (a,b,c) -> b
+thirdOf3 :: (a,b,c) -> c
+fstOf3 (a,_,_) = a
+sndOf3 (_,b,_) = b
+thirdOf3 (_,_,c) = c
+\end{code}
+
%************************************************************************
%* *
\subsection[Utils-lists]{General list processing}
%************************************************************************
%* *
+\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)
+ .|. ((((pm' .&. vp) + vp) .&. vector_mask) `xor` vp) .|. pm' .|. vn
+ -- No need to mask the shiftL because of the restricted range of pm
+
+ 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
+
+fuzzyMatch :: String -> [String] -> [String]
+fuzzyMatch key vals = fuzzyLookup key [(v,v) | v <- vals]
+
+-- | Search for possible matches to the users input in the given list,
+-- returning a small number of ranked results
+fuzzyLookup :: String -> [(String,a)] -> [a]
+fuzzyLookup user_entered possibilites
+ = map fst $ take mAX_RESULTS $ sortBy (comparing snd)
+ [ (poss_val, distance) | (poss_str, poss_val) <- possibilites
+ , let distance = restrictedDamerauLevenshteinDistance
+ poss_str user_entered
+ , distance <= fuzzy_threshold ]
+ where
+ -- Work out an approriate match threshold:
+ -- We report a candidate if its edit distance is <= the threshold,
+ -- The threshhold is set to about a quarter of the # of characters the user entered
+ -- Length Threshold
+ -- 1 0 -- Don't suggest *any* candidates
+ -- 2 1 -- for single-char identifiers
+ -- 3 1
+ -- 4 1
+ -- 5 1
+ -- 6 2
+ --
+ fuzzy_threshold = truncate $ fromIntegral (length user_entered + 2) / (4 :: Rational)
+ 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
-----------------------------------------------------------------------------
+-- read helpers
+
+maybeReadFuzzy :: Read a => String -> Maybe a
+maybeReadFuzzy str = case reads str of
+ [(x, s)]
+ | all isSpace s ->
+ Just x
+ _ ->
+ Nothing
+
+-----------------------------------------------------------------------------
-- Create a hierarchy of directories
createDirectoryHierarchy :: FilePath -> IO ()
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}
+
+%************************************************************************
+%* *
+\subsection[Utils-C]{Utils for printing C code}
+%* *
+%************************************************************************
+
+\begin{code}
+charToC :: Word8 -> String
+charToC w =
+ case chr (fromIntegral w) of
+ '\"' -> "\\\""
+ '\'' -> "\\\'"
+ '\\' -> "\\\\"
+ c | c >= ' ' && c <= '~' -> [c]
+ | otherwise -> ['\\',
+ chr (ord '0' + ord c `div` 64),
+ chr (ord '0' + ord c `div` 8 `mod` 8),
+ chr (ord '0' + ord c `mod` 8)]
+\end{code}
projects / ghc-hetmet.git / blobdiff