src/Advent/List.hs

   1 module Advent.List where
   2
   3 breakBy :: ([a] -> Bool) -> [a] -> ([a], [a])
   4 breakBy _ [] = ([], [])
   5 breakBy p xs@(x:xs')
   6   | p xs      = ([], xs)
   7   | otherwise =
   8     let (ys, zs) = breakBy p xs'
   9     in (x:ys, zs)
  10
  11 split :: Eq a => [a] -> [a] -> [[a]]
  12 split delim [] = []
  13 split delim list =
  14   let (x, xs) = breakBy (\x -> take (length delim) x == delim) list
  15   in x : split delim (drop (length delim) xs)
  16
  17 splitOne :: Eq a => a -> [a] -> [[a]]
  18 splitOne delim [] = []
  19 splitOne delim list =
  20   let (x, xs) = break (==delim) list
  21   in x : splitOne delim (drop 1 xs)
  22
  23 chunks :: Int -> [a] -> [[a]]
  24 chunks n [] = []
  25 chunks n xs = take n xs : chunks n (drop n xs)
  26
  27 count :: (a -> Bool) -> [a] -> Int
  28 count p = length . filter p