webgear-server-0.1.0: src/WebGear/Util.hs

-- |
-- Copyright        : (c) Raghu Kaippully, 2020
-- License          : MPL-2.0
-- Maintainer       : rkaippully@gmail.com
--
-- Common utility functions.
module WebGear.Util
  ( takeWhileM
  , splitOn
  ) where

import Data.List.NonEmpty (NonEmpty (..), toList)


takeWhileM :: Monad m => (a -> Bool) -> [m a] -> m [a]
takeWhileM _    []     = pure []
takeWhileM p (mx:mxs) = do
  x <- mx
  if p x
    then (x :) <$> takeWhileM p mxs
    else pure []

splitOn :: Eq a => a -> [a] -> NonEmpty [a]
splitOn sep = foldr f ([] :| [])
  where
    f x acc       | x == sep = [] :| toList acc
    f x (y :| ys) = (x:y) :| ys