I am relatively new to Haskell, having spent the last half a decade or so developing in Ruby. I am attempting to (for the sake of exercise) implement a split function from the ground up in Haskell, and for the life of me I can not figure out why it doesn't work. Without further ado:

module MyAwesomeModule where

import qualified Data.Text as T

outputSplit :: String -> [String] -> IO ()

outputSplit s tokens = print $ splitRecursive tokens s

splitRecursive :: [String] -> String -> [String]

splitRecursive tokens s = splitOneOf tokens s

splitOneOf :: [String] -> String -> [String]

splitOneOf [] s = []

splitOneOf (t:tokens) s = map (splitOneOf tokens)(map (T.unpack) (T.splitOn (T.pack t) (T.pack s))) ++ (splitOneOf tokens s)

which errors out with:

Couldn't match type `[Char]' with `Char'

Expected type: String -> String

Actual type: String -> [String]

In the return type of a call of `splitOneOf'

In the first argument of `map', namely `(splitOneOf tokens)'

In the first argument of `(++)', namely

`map

(splitOneOf tokens)

(map (T.unpack) (T.splitOn (T.pack t) (T.pack s)))'

Failed, modules loaded: none.

If anyone has any ideas, that would be awesome! And yes, I'm aware of Data.List.Split, like I said, trying to roll my own....