git-annex/Utility/Split.hs
2019-11-27 16:38:18 -04:00

39 lines
950 B
Haskell

{- split utility functions
-
- Copyright 2017 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
{-# OPTIONS_GHC -fno-warn-tabs #-}
module Utility.Split (
split,
splitc,
replace,
dropFromEnd,
) where
import Data.List (intercalate)
import Data.List.Split (splitOn)
-- | same as Data.List.Utils.split
--
-- intercalate x . splitOn x === id
split :: Eq a => [a] -> [a] -> [[a]]
split = splitOn
-- | Split on a single character. This is over twice as fast as using
-- split on a list of length 1, while producing identical results. -}
splitc :: Eq c => c -> [c] -> [[c]]
splitc c s = case break (== c) s of
(i, _c:rest) -> i : splitc c rest
(i, []) -> i : []
-- | same as Data.List.Utils.replace
replace :: Eq a => [a] -> [a] -> [a] -> [a]
replace old new = intercalate new . split old
-- | Only traverses the list once while dropping the last n items.
dropFromEnd :: Int -> [a] -> [a]
dropFromEnd n l = zipWith const l (drop n l)