/usr/lib/hugs/oldlib/BinaryRandList.hs is in hugs 98.200609.21-5.3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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-- See COPYRIGHT file for terms and conditions.
module BinaryRandList
{-# DEPRECATED "This module is unmaintained, and will disappear soon" #-}
(
-- type
Seq, -- instance of Sequence, Functor, Monad, MonadPlus
-- sequence operations
empty,single,cons,snoc,append,lview,lhead,ltail,rview,rhead,rtail,
null,size,concat,reverse,reverseOnto,fromList,toList,
map,concatMap,foldr,foldl,foldr1,foldl1,reducer,reducel,reduce1,
copy,tabulate,inBounds,lookup,lookupM,lookupWithDefault,update,adjust,
mapWithIndex,foldrWithIndex,foldlWithIndex,
take,drop,splitAt,subseq,filter,partition,takeWhile,dropWhile,splitWhile,
zip,zip3,zipWith,zipWith3,unzip,unzip3,unzipWith,unzipWith3,
-- documentation
moduleName,
-- re-export view type from EdisonPrelude for convenience
Maybe2(Just2,Nothing2)
) where
import Prelude hiding (concat,reverse,map,concatMap,foldr,foldl,foldr1,foldl1,
filter,takeWhile,dropWhile,lookup,take,drop,splitAt,
zip,zip3,zipWith,zipWith3,unzip,unzip3,null)
import EdisonPrelude(Maybe2(Just2,Nothing2))
import qualified Sequence as S ( Sequence(..) )
import SequenceDefaults
import Monad
import QuickCheck
-- signatures for exported functions
moduleName :: String
empty :: Seq a
single :: a -> Seq a
cons :: a -> Seq a -> Seq a
snoc :: Seq a -> a -> Seq a
append :: Seq a -> Seq a -> Seq a
lview :: Seq a -> Maybe2 a (Seq a)
lhead :: Seq a -> a
ltail :: Seq a -> Seq a
rview :: Seq a -> Maybe2 (Seq a) a
rhead :: Seq a -> a
rtail :: Seq a -> Seq a
null :: Seq a -> Bool
size :: Seq a -> Int
concat :: Seq (Seq a) -> Seq a
reverse :: Seq a -> Seq a
reverseOnto :: Seq a -> Seq a -> Seq a
fromList :: [a] -> Seq a
toList :: Seq a -> [a]
map :: (a -> b) -> Seq a -> Seq b
concatMap :: (a -> Seq b) -> Seq a -> Seq b
foldr :: (a -> b -> b) -> b -> Seq a -> b
foldl :: (b -> a -> b) -> b -> Seq a -> b
foldr1 :: (a -> a -> a) -> Seq a -> a
foldl1 :: (a -> a -> a) -> Seq a -> a
reducer :: (a -> a -> a) -> a -> Seq a -> a
reducel :: (a -> a -> a) -> a -> Seq a -> a
reduce1 :: (a -> a -> a) -> Seq a -> a
copy :: Int -> a -> Seq a
tabulate :: Int -> (Int -> a) -> Seq a
inBounds :: Seq a -> Int -> Bool
lookup :: Seq a -> Int -> a
lookupM :: Seq a -> Int -> Maybe a
lookupWithDefault :: a -> Seq a -> Int -> a
update :: Int -> a -> Seq a -> Seq a
adjust :: (a -> a) -> Int -> Seq a -> Seq a
mapWithIndex :: (Int -> a -> b) -> Seq a -> Seq b
foldrWithIndex :: (Int -> a -> b -> b) -> b -> Seq a -> b
foldlWithIndex :: (b -> Int -> a -> b) -> b -> Seq a -> b
take :: Int -> Seq a -> Seq a
drop :: Int -> Seq a -> Seq a
splitAt :: Int -> Seq a -> (Seq a, Seq a)
subseq :: Int -> Int -> Seq a -> Seq a
filter :: (a -> Bool) -> Seq a -> Seq a
partition :: (a -> Bool) -> Seq a -> (Seq a, Seq a)
takeWhile :: (a -> Bool) -> Seq a -> Seq a
dropWhile :: (a -> Bool) -> Seq a -> Seq a
splitWhile :: (a -> Bool) -> Seq a -> (Seq a, Seq a)
zip :: Seq a -> Seq b -> Seq (a,b)
zip3 :: Seq a -> Seq b -> Seq c -> Seq (a,b,c)
zipWith :: (a -> b -> c) -> Seq a -> Seq b -> Seq c
zipWith3 :: (a -> b -> c -> d) -> Seq a -> Seq b -> Seq c -> Seq d
unzip :: Seq (a,b) -> (Seq a, Seq b)
unzip3 :: Seq (a,b,c) -> (Seq a, Seq b, Seq c)
unzipWith :: (a -> b) -> (a -> c) -> Seq a -> (Seq b, Seq c)
unzipWith3 :: (a -> b) -> (a -> c) -> (a -> d) -> Seq a -> (Seq b, Seq c, Seq d)
moduleName = "BinaryRandList"
-- Adapted from
-- Chris Okasaki. Purely Functional Data Structures. 1998.
-- Section 10.1.2.
data Seq a = E | Even (Seq (a,a)) | Odd a (Seq (a,a)) deriving (Eq)
-- not exported, rewrite as bit ops?
--even n = (n `mod` 2) == 0
--odd n = (n `mod` 2) <> 0
half n = n `div` 2
mkEven E = E
mkEven ps = Even ps
empty = E
single x = Odd x E
cons x E = Odd x E
cons x (Even ps) = Odd x ps
cons x (Odd y ps) = Even (cons (x,y) ps)
append xs E = xs
append xs ys@(Even pys) =
case xs of
E -> ys
Even pxs -> Even (append pxs pys)
Odd x pxs -> Odd x (append pxs pys)
append xs ys@(Odd _ _) = foldr cons ys xs
copy n x
| n <= 0 = E
| otherwise = cp n x
where cp :: Int -> a' -> Seq a'
cp n x
| odd n = Odd x (cp (half n) (x,x))
| n == 0 = E
| otherwise = Even (cp (half n) (x,x))
lview E = Nothing2
lview (Even ps) = case lview ps of
Just2 (x,y) ps' -> Just2 x (Odd y ps')
lview (Odd x ps) = Just2 x (mkEven ps)
lhead E = error "BinaryRandList.lhead: empty sequence"
lhead (Even ps) = fst (lhead ps)
lhead (Odd x ps) = x
ltail E = E
ltail (Even ps) = case lview ps of
Just2 (x,y) ps' -> Odd y ps'
ltail (Odd x ps) = mkEven ps
rhead E = error "BinaryRandList.rhead: empty sequence"
rhead (Even ps) = snd (rhead ps)
rhead (Odd x E) = x
rhead (Odd x ps) = snd (rhead ps)
null E = True
null _ = False
size E = 0
size (Even ps) = 2 * size ps
size (Odd x ps) = 1 + 2 * size ps
map f E = E
map f (Even ps) = Even (map (\(x,y) -> (f x,f y)) ps)
map f (Odd x ps) = Odd (f x) (map (\(x,y) -> (f x,f y)) ps)
foldr f e E = e
foldr f e (Even ps) = foldr (\(x,y) e -> f x (f y e)) e ps
foldr f e (Odd x ps) = f x (foldr (\(x,y) e -> f x (f y e)) e ps)
foldl f e E = e
foldl f e (Even ps) = foldl (\e (x,y) -> f (f e x) y) e ps
foldl f e (Odd x ps) = foldl (\e (x,y) -> f (f e x) y) (f e x) ps
reduce1 f E = error "BinaryRandList.reduce1: empty seq"
reduce1 f (Even ps) = reduce1 f (map (uncurry f) ps)
reduce1 f (Odd x E) = x
reduce1 f (Odd x ps) = f x (reduce1 f (map (uncurry f) ps))
inBounds xs i = (i >= 0) && inb xs i
where inb :: Seq a' -> Int -> Bool
inb E i = False
inb (Even ps) i = inb ps (half i)
inb (Odd x ps) i = (i == 0) || inb ps (half (i-1))
lookup xs i
| i < 0 = error "BinaryRandList.lookup: bad subscript"
| otherwise = look xs i
where look :: Seq a' -> Int -> a'
look E i = error "BinaryRandList.lookup: bad subscript"
look (Even ps) i = if even i then x else y
where (x,y) = look ps (half i)
look (Odd x ps) i
| odd i = fst (look ps (half (i-1)))
| i == 0 = x
| otherwise = snd (look ps (half (i-1)))
lookupM xs i
| i < 0 = Nothing
| otherwise = lookFun Nothing xs i Just
lookupWithDefault d xs i
| i < 0 = d
| otherwise = lookFun d xs i id
-- not exported
lookFun :: b -> Seq a -> Int -> (a -> b) -> b
lookFun d E i f = d
lookFun d (Even ps) i f
| even i = lookFun d ps (half i) (f . fst)
| otherwise = lookFun d ps (half i) (f . snd)
lookFun d (Odd x ps) i f
| odd i = lookFun d ps (half (i-1)) (f . fst)
| i == 0 = f x
| otherwise = lookFun d ps (half (i-1)) (f . snd)
adjust f i xs
| i < 0 = xs
| otherwise = adj f i xs
where adj :: (a' -> a') -> Int -> Seq a' -> Seq a'
adj f i E = E
adj f i (Even ps)
| even i = Even (adj (mapFst f) (half i) ps)
| otherwise = Even (adj (mapSnd f) (half i) ps)
adj f i (Odd x ps)
| odd i = Odd x (adj (mapFst f) (half (i-1)) ps)
| i == 0 = Odd (f x) ps
| otherwise = Odd x (adj (mapSnd f) (half (i-1)) ps)
-- not exported
mapFst f (x,y) = (f x,y)
mapSnd f (x,y) = (x,f y)
take n xs = if n <= 0 then E else tak n xs
where tak :: Int -> Seq a' -> Seq a'
tak 0 xs = E
tak i E = E
tak i (Even ps)
| even i = Even (tak (half i) ps)
tak i (Odd x ps)
| odd i = Odd x (tak (half (i-1)) ps)
tak i xs = takeUsingLists i xs
-- drop is O(log^2 n) instead of O(log n)??
drop n xs = if n <= 0 then xs else drp n xs
where drp :: Int -> Seq a' -> Seq a'
drp 0 xs = xs
drp i E = E
drp i (Even ps)
| even i = mkEven (drp (half i) ps)
| otherwise = ltail (mkEven (drp (half i) ps))
drp i (Odd _ ps)
| odd i = mkEven (drp (half (i-1)) ps)
| otherwise = ltail (mkEven (drp (half (i-1)) ps))
-- the remaining functions all use defaults
snoc = snocUsingFoldr
rview = rviewDefault
rtail = rtailUsingLview
concat = concatUsingFoldr
reverse = reverseUsingReverseOnto
reverseOnto = reverseOntoUsingFoldl
fromList = fromListUsingCons
toList = toListUsingFoldr
concatMap = concatMapUsingFoldr
foldr1 = foldr1UsingLview
foldl1 = foldl1UsingFoldl
reducer = reducerUsingReduce1
reducel = reducelUsingReduce1
tabulate = tabulateUsingLists
update = updateUsingAdjust
mapWithIndex = mapWithIndexUsingLists
foldrWithIndex = foldrWithIndexUsingLists
foldlWithIndex = foldlWithIndexUsingLists
splitAt = splitAtDefault
filter = filterUsingFoldr
partition = partitionUsingFoldr
subseq = subseqDefault
takeWhile = takeWhileUsingLview
dropWhile = dropWhileUsingLview
splitWhile = splitWhileUsingLview
-- for zips, could optimize by calculating which one is shorter and
-- retaining its shape
zip = zipUsingLists
zip3 = zip3UsingLists
zipWith = zipWithUsingLists
zipWith3 = zipWith3UsingLists
unzip = unzipUsingLists
unzip3 = unzip3UsingLists
unzipWith = unzipWithUsingLists
unzipWith3 = unzipWith3UsingLists
-- instances
instance S.Sequence Seq where
{empty = empty; single = single; cons = cons; snoc = snoc;
append = append; lview = lview; lhead = lhead; ltail = ltail;
rview = rview; rhead = rhead; rtail = rtail; null = null;
size = size; concat = concat; reverse = reverse;
reverseOnto = reverseOnto; fromList = fromList; toList = toList;
map = map; concatMap = concatMap; foldr = foldr; foldl = foldl;
foldr1 = foldr1; foldl1 = foldl1; reducer = reducer;
reducel = reducel; reduce1 = reduce1; copy = copy;
tabulate = tabulate; inBounds = inBounds; lookup = lookup;
lookupM = lookupM; lookupWithDefault = lookupWithDefault;
update = update; adjust = adjust; mapWithIndex = mapWithIndex;
foldrWithIndex = foldrWithIndex; foldlWithIndex = foldlWithIndex;
take = take; drop = drop; splitAt = splitAt; subseq = subseq;
filter = filter; partition = partition; takeWhile = takeWhile;
dropWhile = dropWhile; splitWhile = splitWhile; zip = zip;
zip3 = zip3; zipWith = zipWith; zipWith3 = zipWith3; unzip = unzip;
unzip3 = unzip3; unzipWith = unzipWith; unzipWith3 = unzipWith3;
instanceName s = moduleName}
instance Functor Seq where
fmap = map
instance Monad Seq where
return = single
xs >>= k = concatMap k xs
instance MonadPlus Seq where
mplus = append
mzero = empty
-- instance Eq (Seq a) is derived
instance Show a => Show (Seq a) where
show xs = show (toList xs)
instance Arbitrary a => Arbitrary (Seq a) where
arbitrary = do xs <- arbitrary
return (fromList xs)
coarbitrary E = variant 0
coarbitrary (Even ps) = variant 1 . coarbitrary ps
coarbitrary (Odd x ps) = variant 2 . coarbitrary x . coarbitrary ps
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