Safe Haskell | None |
---|---|

Language | Haskell2010 |

- Flags dependent on the compiler build
- General list processing
- Tuples
- List operations controlled by another list
- For loop
- Sorting
- Comparisons
- Edit distance
- Transitive closures
- Strictness
- Module names
- Argument processing
- Floating point
- read helpers
- IO-ish utilities
- Filenames and paths
- Utils for defining Data instances
- Utils for printing C code
- Hashing

Highly random utility functions

- ghciSupported :: Bool
- debugIsOn :: Bool
- ncgDebugIsOn :: Bool
- ghciTablesNextToCode :: Bool
- isWindowsHost :: Bool
- isDarwinHost :: Bool
- zipEqual :: String -> [a] -> [b] -> [(a, b)]
- zipWithEqual :: String -> (a -> b -> c) -> [a] -> [b] -> [c]
- zipWith3Equal :: String -> (a -> b -> c -> d) -> [a] -> [b] -> [c] -> [d]
- zipWith4Equal :: String -> (a -> b -> c -> d -> e) -> [a] -> [b] -> [c] -> [d] -> [e]
- zipLazy :: [a] -> [b] -> [(a, b)]
- stretchZipWith :: (a -> Bool) -> b -> (a -> b -> c) -> [a] -> [b] -> [c]
- zipWithAndUnzip :: (a -> b -> (c, d)) -> [a] -> [b] -> ([c], [d])
- zipWithLazy :: (a -> b -> c) -> [a] -> [b] -> [c]
- zipWith3Lazy :: (a -> b -> c -> d) -> [a] -> [b] -> [c] -> [d]
- filterByList :: [Bool] -> [a] -> [a]
- filterByLists :: [Bool] -> [a] -> [a] -> [a]
- partitionByList :: [Bool] -> [a] -> ([a], [a])
- unzipWith :: (a -> b -> c) -> [(a, b)] -> [c]
- mapFst :: (a -> c) -> [(a, b)] -> [(c, b)]
- mapSnd :: (b -> c) -> [(a, b)] -> [(a, c)]
- chkAppend :: [a] -> [a] -> [a]
- mapAndUnzip :: (a -> (b, c)) -> [a] -> ([b], [c])
- mapAndUnzip3 :: (a -> (b, c, d)) -> [a] -> ([b], [c], [d])
- mapAccumL2 :: (s1 -> s2 -> a -> (s1, s2, b)) -> s1 -> s2 -> [a] -> (s1, s2, [b])
- nOfThem :: Int -> a -> [a]
- filterOut :: (a -> Bool) -> [a] -> [a]
- partitionWith :: (a -> Either b c) -> [a] -> ([b], [c])
- splitEithers :: [Either a b] -> ([a], [b])
- dropWhileEndLE :: (a -> Bool) -> [a] -> [a]
- spanEnd :: (a -> Bool) -> [a] -> ([a], [a])
- foldl1' :: (a -> a -> a) -> [a] -> a
- foldl2 :: (acc -> a -> b -> acc) -> acc -> [a] -> [b] -> acc
- count :: (a -> Bool) -> [a] -> Int
- all2 :: (a -> b -> Bool) -> [a] -> [b] -> Bool
- lengthExceeds :: [a] -> Int -> Bool
- lengthIs :: [a] -> Int -> Bool
- lengthAtLeast :: [a] -> Int -> Bool
- listLengthCmp :: [a] -> Int -> Ordering
- atLength :: ([a] -> b) -> b -> [a] -> Int -> b
- equalLength :: [a] -> [b] -> Bool
- compareLength :: [a] -> [b] -> Ordering
- leLength :: [a] -> [b] -> Bool
- isSingleton :: [a] -> Bool
- only :: [a] -> a
- singleton :: a -> [a]
- notNull :: [a] -> Bool
- snocView :: [a] -> Maybe ([a], a)
- isIn :: Eq a => String -> a -> [a] -> Bool
- isn'tIn :: Eq a => String -> a -> [a] -> Bool
- chunkList :: Int -> [a] -> [[a]]
- fstOf3 :: (a, b, c) -> a
- sndOf3 :: (a, b, c) -> b
- thdOf3 :: (a, b, c) -> c
- firstM :: Monad m => (a -> m c) -> (a, b) -> m (c, b)
- first3M :: Monad m => (a -> m d) -> (a, b, c) -> m (d, b, c)
- fst3 :: (a -> d) -> (a, b, c) -> (d, b, c)
- snd3 :: (b -> d) -> (a, b, c) -> (a, d, c)
- third3 :: (c -> d) -> (a, b, c) -> (a, b, d)
- uncurry3 :: (a -> b -> c -> d) -> (a, b, c) -> d
- liftFst :: (a -> b) -> (a, c) -> (b, c)
- liftSnd :: (a -> b) -> (c, a) -> (c, b)
- takeList :: [b] -> [a] -> [a]
- dropList :: [b] -> [a] -> [a]
- splitAtList :: [b] -> [a] -> ([a], [a])
- split :: Char -> String -> [String]
- dropTail :: Int -> [a] -> [a]
- nTimes :: Int -> (a -> a) -> a -> a
- sortWith :: Ord b => (a -> b) -> [a] -> [a]
- minWith :: Ord b => (a -> b) -> [a] -> a
- nubSort :: Ord a => [a] -> [a]
- isEqual :: Ordering -> Bool
- eqListBy :: (a -> a -> Bool) -> [a] -> [a] -> Bool
- eqMaybeBy :: (a -> a -> Bool) -> Maybe a -> Maybe a -> Bool
- thenCmp :: Ordering -> Ordering -> Ordering
- cmpList :: (a -> a -> Ordering) -> [a] -> [a] -> Ordering
- removeSpaces :: String -> String
- (<&&>) :: Applicative f => f Bool -> f Bool -> f Bool
- (<||>) :: Applicative f => f Bool -> f Bool -> f Bool
- fuzzyMatch :: String -> [String] -> [String]
- fuzzyLookup :: String -> [(String, a)] -> [a]
- transitiveClosure :: (a -> [a]) -> (a -> a -> Bool) -> [a] -> [a]
- seqList :: [a] -> b -> b
- looksLikeModuleName :: String -> Bool
- looksLikePackageName :: String -> Bool
- getCmd :: String -> Either String (String, String)
- toCmdArgs :: String -> Either String (String, [String])
- toArgs :: String -> Either String [String]
- readRational :: String -> Rational
- maybeRead :: Read a => String -> Maybe a
- maybeReadFuzzy :: Read a => String -> Maybe a
- doesDirNameExist :: FilePath -> IO Bool
- getModificationUTCTime :: FilePath -> IO UTCTime
- modificationTimeIfExists :: FilePath -> IO (Maybe UTCTime)
- hSetTranslit :: Handle -> IO ()
- global :: a -> IORef a
- consIORef :: IORef [a] -> a -> IO ()
- globalM :: IO a -> IORef a
- type Suffix = String
- splitLongestPrefix :: String -> (Char -> Bool) -> (String, String)
- escapeSpaces :: String -> String
- data Direction
- reslash :: Direction -> FilePath -> FilePath
- makeRelativeTo :: FilePath -> FilePath -> FilePath
- abstractConstr :: String -> Constr
- abstractDataType :: String -> DataType
- mkNoRepType :: String -> DataType
- charToC :: Word8 -> String
- hashString :: String -> Int32

# Flags dependent on the compiler build

ghciSupported :: Bool #

ncgDebugIsOn :: Bool #

isWindowsHost :: Bool #

isDarwinHost :: Bool #

# General list processing

zipWithEqual :: String -> (a -> b -> c) -> [a] -> [b] -> [c] #

zipWith3Equal :: String -> (a -> b -> c -> d) -> [a] -> [b] -> [c] -> [d] #

zipWith4Equal :: String -> (a -> b -> c -> d -> e) -> [a] -> [b] -> [c] -> [d] -> [e] #

stretchZipWith :: (a -> Bool) -> b -> (a -> b -> c) -> [a] -> [b] -> [c] #

`stretchZipWith p z f xs ys`

stretches `ys`

by inserting `z`

in
the places where `p`

returns `True`

zipWithAndUnzip :: (a -> b -> (c, d)) -> [a] -> [b] -> ([c], [d]) #

zipWithLazy :: (a -> b -> c) -> [a] -> [b] -> [c] #

`zipWithLazy`

is like `zipWith`

but is lazy in the second list.
The length of the output is always the same as the length of the first
list.

zipWith3Lazy :: (a -> b -> c -> d) -> [a] -> [b] -> [c] -> [d] #

`zipWith3Lazy`

is like `zipWith3`

but is lazy in the second and third lists.
The length of the output is always the same as the length of the first
list.

filterByList :: [Bool] -> [a] -> [a] #

`filterByList`

takes a list of Bools and a list of some elements and
filters out these elements for which the corresponding value in the list of
Bools is False. This function does not check whether the lists have equal
length.

filterByLists :: [Bool] -> [a] -> [a] -> [a] #

`filterByLists`

takes a list of Bools and two lists as input, and
outputs a new list consisting of elements from the last two input lists. For
each Bool in the list, if it is `True`

, then it takes an element from the
former list. If it is `False`

, it takes an element from the latter list.
The elements taken correspond to the index of the Bool in its list.
For example:

filterByLists [True, False, True, False] "abcd" "wxyz" = "axcz"

This function does not check whether the lists have equal length.

partitionByList :: [Bool] -> [a] -> ([a], [a]) #

`partitionByList`

takes a list of Bools and a list of some elements and
partitions the list according to the list of Bools. Elements corresponding
to `True`

go to the left; elements corresponding to `False`

go to the right.
For example, `partitionByList [True, False, True] [1,2,3] == ([1,3], [2])`

This function does not check whether the lists have equal
length.

mapAndUnzip :: (a -> (b, c)) -> [a] -> ([b], [c]) #

mapAndUnzip3 :: (a -> (b, c, d)) -> [a] -> ([b], [c], [d]) #

mapAccumL2 :: (s1 -> s2 -> a -> (s1, s2, b)) -> s1 -> s2 -> [a] -> (s1, s2, [b]) #

partitionWith :: (a -> Either b c) -> [a] -> ([b], [c]) #

Uses a function to determine which of two output lists an input element should join

splitEithers :: [Either a b] -> ([a], [b]) #

Teases a list of `Either`

s apart into two lists

dropWhileEndLE :: (a -> Bool) -> [a] -> [a] #

spanEnd :: (a -> Bool) -> [a] -> ([a], [a]) #

`spanEnd p l == reverse (span p (reverse l))`

. The first list
returns actually comes after the second list (when you look at the
input list).

lengthExceeds :: [a] -> Int -> Bool #

(lengthExceeds xs n) = (length xs > n)

lengthAtLeast :: [a] -> Int -> Bool #

listLengthCmp :: [a] -> Int -> Ordering #

atLength :: ([a] -> b) -> b -> [a] -> Int -> b #

`atLength atLen atEnd ls n`

unravels list `ls`

to position `n`

. Precisely:

atLength atLenPred atEndPred ls n | n < 0 = atLenPred ls | length ls < n = atEndPred (n - length ls) | otherwise = atLenPred (drop n ls)

equalLength :: [a] -> [b] -> Bool #

compareLength :: [a] -> [b] -> Ordering #

isSingleton :: [a] -> Bool #

# Tuples

# List operations controlled by another list

splitAtList :: [b] -> [a] -> ([a], [a]) #

# For loop

nTimes :: Int -> (a -> a) -> a -> a #

Compose a function with itself n times. (nth rather than twice)

# Sorting

sortWith :: Ord b => (a -> b) -> [a] -> [a] Source #

The `sortWith`

function sorts a list of elements using the
user supplied function to project something out of each element

# Comparisons

removeSpaces :: String -> String #

# Edit distance

fuzzyMatch :: String -> [String] -> [String] #

fuzzyLookup :: String -> [(String, a)] -> [a] #

Search for possible matches to the users input in the given list, returning a small number of ranked results

# Transitive closures

transitiveClosure :: (a -> [a]) -> (a -> a -> Bool) -> [a] -> [a] #

# Strictness

# Module names

looksLikeModuleName :: String -> Bool #

looksLikePackageName :: String -> Bool #

# Argument processing

# Floating point

readRational :: String -> Rational #

# read helpers

maybeReadFuzzy :: Read a => String -> Maybe a #

# IO-ish utilities

doesDirNameExist :: FilePath -> IO Bool #

getModificationUTCTime :: FilePath -> IO UTCTime #

hSetTranslit :: Handle -> IO () #

# Filenames and paths

escapeSpaces :: String -> String #

makeRelativeTo :: FilePath -> FilePath -> FilePath #

# Utils for defining Data instances

abstractConstr :: String -> Constr #

abstractDataType :: String -> DataType #

mkNoRepType :: String -> DataType Source #

Constructs a non-representation for a non-representable type

# Utils for printing C code

# Hashing

hashString :: String -> Int32 #

A sample hash function for Strings. We keep multiplying by the golden ratio and adding. The implementation is:

hashString = foldl' f golden where f m c = fromIntegral (ord c) * magic + hashInt32 m magic = 0xdeadbeef

Where hashInt32 works just as hashInt shown above.

Knuth argues that repeated multiplication by the golden ratio will minimize gaps in the hash space, and thus it's a good choice for combining together multiple keys to form one.

Here we know that individual characters c are often small, and this produces frequent collisions if we use ord c alone. A particular problem are the shorter low ASCII and ISO-8859-1 character strings. We pre-multiply by a magic twiddle factor to obtain a good distribution. In fact, given the following test:

testp :: Int32 -> Int testp k = (n - ) . length . group . sort . map hs . take n $ ls where ls = [] : [c : l | l <- ls, c <- ['\0'..'\xff']] hs = foldl' f golden f m c = fromIntegral (ord c) * k + hashInt32 m n = 100000

We discover that testp magic = 0.