44 lines
1 KiB
Haskell
44 lines
1 KiB
Haskell
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{-# LANGUAGE OverloadedStrings #-}
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module Day03 (parse, solveA, solveB) where
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import Data.Bifunctor (first)
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import Data.Void (Void)
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import Data.Char (digitToInt, isSpace)
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import Data.Text (Text)
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import Text.Megaparsec (errorBundlePretty, Parsec, runParser, many, eof, choice, satisfy, manyTill)
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import Text.Megaparsec.Char (digitChar, char)
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data Item
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= Digit Int
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| Symbol Char
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| Empty
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deriving (Show, Eq)
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type Parser = Parsec Void Text
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parse :: Text -> Either String [[Item]]
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parse = first errorBundlePretty . runParser full ""
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where
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item :: Parser Item
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item = choice
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[ Digit . digitToInt <$> digitChar
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, Empty <$ char '.'
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, Symbol <$> satisfy (not . isSpace)
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]
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line :: Parser [Item]
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line = item `manyTill` satisfy isSpace
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full :: Parser [[Item]]
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full = many line <* eof
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solveA :: [[Item]] -> Int
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solveA = const 1
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solveB :: [[Item]] -> Int
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solveB = const 2
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-- >>> parse input
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-- Right [Digit 4,Digit 6,Digit 7,Empty,Empty,Digit 1,Digit 1,Digit 4,Empty,Empty]
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