1 -- | The Misc module contains helper functions that seem out of place
7 -- | The standard factorial function. See
8 -- <http://www.willamette.edu/~fruehr/haskell/evolution.html> for
9 -- possible improvements.
19 factorial :: Int -> Int
22 | n > 20 = error "integer overflow in factorial function"
23 | otherwise = product [1..n]
26 -- | Takes a three-dimensional list, and flattens it into a
27 -- one-dimensional one.
28 flatten :: [[[a]]] -> [a]
29 flatten xs = concat $ concat xs
32 -- | Takes a list, and returns True if its elements are pairwise
33 -- equal. Returns False otherwise.
34 all_equal :: (Eq a) => [a] -> Bool
36 all (== first_element) other_elements
38 first_element = head xs
39 other_elements = tail xs