17 lines
418 B
Haskell
17 lines
418 B
Haskell
import Data.Char (ord, chr)
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import Data.Ix (inRange)
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caesar :: Int -> String -> String
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caesar k = map f
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where
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f c
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| inRange ('a','z') c = tr 'a' k c
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| inRange ('A','Z') c = tr 'A' k c
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| otherwise = c
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unCaesar :: Int -> String -> String
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unCaesar k = caesar (-k)
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-- char addition
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tr :: Char -> Int -> Char -> Char
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tr base offset char = chr $ ord base + (ord char - ord base + offset) `mod` 26
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