44 lines
1.1 KiB
Haskell
44 lines
1.1 KiB
Haskell
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import Data.Char (isDigit, isSpace)
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data Color = Red | Green | Blue deriving (Show, Eq)
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-- Parse a single digit
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digit :: Char -> Maybe Int
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digit c
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| isDigit c = Just (read [c])
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| otherwise = Nothing
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-- Parse an integer
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-- Parse an integer
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parseInt :: String -> Maybe Int
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parseInt str = case reads str of
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[(num, "")] -> Just num
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_ -> Nothing
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-- Parse color
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parseColor :: String -> Maybe Color
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parseColor "red" = Just Red
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parseColor "green" = Just Green
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parseColor "blue" = Just Blue
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parseColor _ = Nothing
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-- Parse the entire input string
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parseInput :: String -> Maybe Bool
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parseInput input = do
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let (numStr, rest) = span (\c -> isDigit c ) input
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num <- parseInt numStr
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let colorStr = dropWhile isSpace rest
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color <- parseColor colorStr
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case color of
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Red -> pure (num < 12)
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Green -> pure (num < 13)
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Blue -> pure (num < 14)
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main :: IO ()
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main = do
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putStrLn "Enter input (e.g., '10 red'):"
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input <- getLine
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case parseInput input of
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Just result -> putStrLn $ "Result: " ++ show result
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Nothing -> putStrLn "Invalid input."
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