Created
July 26, 2020 14:47
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view patterns https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/glasgow_exts.html#extension-ViewPatterns
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{-# LANGUAGE ViewPatterns #-} | |
module Main where | |
import Data.Char | |
import qualified Data.List | |
import Data.Text | |
data SplitState | |
= BreakingOnSpace | |
| BreakingOnNonSpace | |
splitty :: Text -> [Either Text Text] | |
splitty = \t -> Data.List.unfoldr (uncurry step) (BreakingOnSpace, t) | |
where | |
step :: SplitState -> Text -> Maybe (Either Text Text, (SplitState, Text)) | |
step _ t | |
| Data.Text.null t = | |
Nothing | |
step (break' -> (sstate, ctor, br)) (br -> (t0, rest)) = | |
Just (ctor t0, (sstate, rest)) | |
break' :: SplitState -> (SplitState, Text -> Either Text Text, Text -> (Text, Text)) | |
break' BreakingOnSpace = (BreakingOnNonSpace, Right, Data.Text.break isSpace) | |
break' BreakingOnNonSpace = (BreakingOnSpace, Left, Data.Text.break (not . isSpace)) | |
main :: IO () | |
main = return () |
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