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22 lines
458 B
Idris
22 lines
458 B
Idris
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module Main
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import Data.Strings
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import Data.Vect
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import System
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%default total
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ints : Vect 4 Int
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ints = [1, 2, 3, 4]
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main : IO ()
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main = do
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[_, arg] <- getArgs
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| _ => do putStrLn "One argument expected."
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exitFailure
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let n = stringToNatOrZ arg
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case natToFin n (length ints + 1) of
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Nothing => do putStrLn "Invalid number."
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exitFailure
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Just (FS i) => putStrLn $ "Value: " ++ show (index i ints)
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