46 lines
1.4 KiB
Haskell
46 lines
1.4 KiB
Haskell
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{-# LANGUAGE RecordWildCards #-}
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--------------------------------------------------------------------------------
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module Main where
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--------------------------------------------------------------------------------
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import Options.Applicative
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import Data.Semigroup ((<>))
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import qualified System.Environment as Env
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--------------------------------------------------------------------------------
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data CommandArgs = CommandArgs
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{ hello :: String
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, quiet :: Bool
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, enthusiasm :: Int
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} deriving (Eq, Show)
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parseArgs :: Parser CommandArgs
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parseArgs =
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CommandArgs <$> strOption
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( long "hello"
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<> metavar "TARGET"
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<> help "Target for the greeting" )
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<*> switch
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( long "quiet"
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<> short 'q'
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<> help "Whether to be quiet" )
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<*> option auto
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( long "enthusiasm"
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<> help "How enthusiastic to greet"
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<> showDefault
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<> value 1
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<> metavar "INT" )
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main :: IO ()
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main = do
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args <- execParser opts
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greet args
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where
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opts = info (parseArgs <**> helper)
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( fullDesc
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<> progDesc "Print a greeting for TARGET"
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<> header "header - a test for optparse-applicative" )
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greet :: CommandArgs -> IO ()
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greet CommandArgs{..} = putStrLn $ "Hello, " ++ hello ++ replicate enthusiasm '!'
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