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| {-# LANGUAGE LambdaCase #-} | |
| module Lib | |
| where | |
| import Text.Megaparsec | |
| import Data.Void (Void) | |
| import Text.Megaparsec.Char (digitChar) | |
| import Data.Function ((&)) | |
| type Parser = Parsec Void String | |
| main :: IO () | |
| main = do | |
| let input = "11111333" | |
| parse p "p" input & \case | |
| Left e -> error $ show e | |
| Right r -> print r -- should print (11111, 333) | |
| return () | |
| where | |
| p :: Parser (Int, Int) | |
| p = | |
| do | |
| l <- takeP (Just "Limited input: 5 characters") 5 | |
| l' <- takeRest | |
| setInput l | |
| a <- customInt-- TODO limit input to 5 characters just for this `customInt` | |
| setInput l' | |
| b <- customInt -- take the remaining 3 (already limited) | |
| return (a, b) | |
| customInt :: Parser Int | |
| customInt = read <$> many digitChar | |
| {- | |
| ghci> main | |
| (11111,333) | |
| 1:5: | |
| | | |
| 1 | 1111 | |
| | ^ | |
| unexpected end of input | |
| expecting Limited input: 5 characters | |
| -} |
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