Drop argparser

alea.cabal

@@ -29,5 +29,6 @@ executable alea
   default-language:    Haskell2010
   other-modules:       Alea.Diceware
   other-extensions:    DeriveDataTypeable, RecordWildCards
-  build-depends:       base >=4.8 && < 5.0, random, text, argparser
+  build-depends:       base >=4.8 && < 5.0, random, text,
+                       optparse-applicative 
   ghc-options:         -O2

src/Main.hs

@@ -2,7 +2,7 @@
 
 import Control.Monad             (when, forever)
 import Data.Text                 (unpack)
-import System.Console.ArgParser
+import Options.Applicative
 import Alea.Diceware
 import Paths_alea                (getDataFileName)
 
@@ -13,55 +13,67 @@ import qualified Data.Text.IO as I
 -- * Command line interface description
 
 -- | Program arguments record
-data ProgArgs = ProgArgs
+data Options = Options
   { interactive  :: Bool
-  , dictionary   :: FilePath
+  , dictionary   :: Maybe FilePath
   , phraseLength :: Int
   , phrases      :: Int
-  } deriving (Show)
+  }
 
 
--- | Default dictionary path
+-- | Argument parser 
-defaultPath :: IO FilePath
+options :: Parser Options
-defaultPath = getDataFileName "dict/diceware"
+options = Options 
+  <$> switch
+      ( long "interactive"
+     <> help "Manually insert numbers from a dice" )
+  <*> optional (option auto
+      ( long "dictionary"
+     <> metavar "FILEPATH"
+     <> help "Specify dictionary filepath" ))
+  <*> option auto
+      ( long "length"
+     <> value 6
+     <> metavar "N"
+     <> help "Number of words in a passphrase")
+  <*> option auto
+     ( long "phrases"
+    <> value 1
+    <> metavar "M"
+    <> help "Number of passphrases to generate" )
+  
 
+-- | Program description
+description :: ParserInfo Options
+description = info (helper <*> options)
+  ( fullDesc
+ <> progDesc "A diceware passphrase generator"
+ <> footer "Alea iacta est." )
 
--- | Arguments descriptions
-argParser :: FilePath -> ParserSpec ProgArgs
-argParser path = ProgArgs
-  `parsedBy` boolFlag      "interactive" `Descr` "Manually insert numbers"
-  `andBy`    optFlag  path "dictionary"  `Descr` "Specify dictionary filepath"
-  `andBy`    optFlag  6    "lenght"      `Descr` "Number of words in a passphrase"
-  `andBy`    optFlag  1    "phrases"     `Descr` "Number of passphrases to generate"
-
-
--- | CLI interface
-interface :: FilePath -> IO (CmdLnInterface ProgArgs)
-interface path = 
-  (`setAppDescr`  "A diceware passphrase generator") <$>
-  (`setAppEpilog` "Alea iacta est.")                 <$>
-  mkApp (argParser path) 
 
 
 -- * Program
 
 -- | Main function
 main :: IO ()
-main = defaultPath >>= interface >>= (`runApp` diceware)
+main = execParser description >>= diceware
 
 
 -- | Actual application 
-diceware :: ProgArgs -> IO ()
+diceware :: Options -> IO ()
-diceware args@ProgArgs{..} = do
+diceware opts@Options{..} = do
-  dict <- fmap parseDiceware (I.readFile dictionary)
+  path <- case dictionary of
+    Nothing -> getDataFileName "dict/diceware"
+    Just x  -> return x
+  dict <- parseDiceware <$> I.readFile path
   let size  = length dict-1
       dice  = readDiceware  dict . read . unpack
       dice' = readDiceware' dict
 
   if interactive
-    then forever (fmap dice I.getLine >>= I.putStrLn)
+    then forever (dice <$> I.getLine >>= I.putStrLn)
     else do
       indices <- randIndices size phraseLength
       I.putStrLn $ T.unwords (map dice' indices)
       when (phrases > 1) $
-        diceware args {phrases = phrases - 1}
+        diceware opts {phrases = phrases - 1}