{-# INLINE partition #-}
partition p xs = foldr (select p) ([],[]) xs
-select p x ~(ts,fs) | p x = (x:ts,fs)
- | otherwise = (ts, x:fs)
+select p x (ts,fs) | p x = (x:ts,fs)
+ | otherwise = (ts, x:fs)
\end{code}
@mapAccumL@ behaves like a combination
Just (a,new_b) -> a : unfoldr f new_b
Nothing -> []
\end{code}
-
-#if 0 /* should go in PrelList, but dependency problems */
-foldl' is a strict version of foldl; that is, it doesn't build up a
-huge suspension in its first argument as it traverses the list. Valid
-when f is strict.
-
-\begin{code}
-foldl' :: (a -> b -> a) -> a -> [b] -> a
-foldl' _ z [] = z
-foldl' f z (x:xs) = let a = f z x in seq a (foldl f a xs)
-
-foldl1' :: (a -> a -> a) -> [a] -> a
-foldl1' f (x:xs) = foldl' f x xs
-foldl1' _ [] = errorEmptyList "foldl1'"
-
-{-# RULES
-"maximumInt" maximum = maximum' :: [Int] -> Int
-"maximumInteger" maximum = maximum' :: [Integer] -> Integer
-"minimumInt" minimum = minimum' :: [Int] -> Int
-"minimumInteger" minimum = minimum' :: [Integer] -> Integer
- #-}
-
-{-# SPECIALISE maximum' :: [Int] -> Int #-}
-{-# SPECIALISE minimum' :: [Int] -> Int #-}
-
-maximum' [] = errorEmptyList "maximum'"
-maximum' xs = foldl1' max xs
-
-minimum' [] = errorEmptyList "minimum'"
-minimum' xs = foldl1' min xs
-\end{code}
-#endif