7L7W.hs

module Main where

import Data.Char (digitToInt)

sort :: (Ord a) => [a] -> [a]
sort [] = []
sort (x:xs) = sort smaller ++ [x] ++ sort greater
  where
    smaller = filter (not.(> x)) xs
    greater = filter (> x) xs

sortBy :: (a -> a -> Ordering) -> [a] -> [a]
sortBy _ [] = []
sortBy cmp (x:xs) = sortBy cmp smaller ++ [x] ++ sortBy cmp greater
  where
    smaller = filter ((/= GT).(`cmp` x)) xs
    greater = filter ((== GT).(`cmp` x)) xs

toNumber :: String -> Double
toNumber = read . filter (`elem` '.':['0'..'9'])

gap2 :: Int -> [Int]
gap2 x = x : (gap2 (x+2))

gap4 :: Int -> [Int]
gap4 x = x : (gap4 (x+4))

gap7 :: Int -> Int -> [Int]
gap7 x y = undefined

half = (/2)

newline = (++"\n")