content: {-# LANGUAGE CPP #-}
  
  -------------------------------------------------------------------------------
  --
  -- | Command-line parser
  --
  -- This is an abstract command-line parser used by both StaticFlags and
  -- DynFlags.
  --
  -- (c) The University of Glasgow 2005
  --
  -------------------------------------------------------------------------------
  
  module Eta.Main.CmdLineParser
      (
        processArgs, OptKind(..), GhcFlagMode(..),
        CmdLineP(..), getCmdLineState, putCmdLineState,
        Flag(..), defFlag, defGhcFlag, defGhciFlag, defHiddenFlag,
        errorsToGhcException,
  
        EwM, runEwM, addErr, addWarn, getArg, getCurLoc, liftEwM, deprecate
      ) where
  
  #include "HsVersions.h"
  
  import Eta.Utils.Util
  import Eta.Utils.Outputable
  import Eta.Utils.Panic
  import Eta.Utils.Bag
  import Eta.BasicTypes.SrcLoc
  
  import Data.Function
  import Data.List
  
  import Control.Monad (liftM, ap)
  #if __GLASGOW_HASKELL__ < 709
  import Control.Applicative (Applicative(..))
  #endif
  
  --------------------------------------------------------
  --         The Flag and OptKind types
  --------------------------------------------------------
  
  data Flag m = Flag
      {   flagName    :: String,     -- Flag, without the leading "-"
          flagOptKind :: OptKind m,  -- What to do if we see it
          flagGhcMode :: GhcFlagMode    -- Which modes this flag affects
      }
  
  defFlag :: String -> OptKind m -> Flag m
  defFlag name optKind = Flag name optKind AllModes
  
  defGhcFlag :: String -> OptKind m -> Flag m
  defGhcFlag name optKind = Flag name optKind OnlyGhc
  
  defGhciFlag :: String -> OptKind m -> Flag m
  defGhciFlag name optKind = Flag name optKind OnlyGhci
  
  defHiddenFlag :: String -> OptKind m -> Flag m
  defHiddenFlag name optKind = Flag name optKind HiddenFlag
  
  -- | GHC flag modes describing when a flag has an effect.
  data GhcFlagMode
      = OnlyGhc  -- ^ The flag only affects the non-interactive GHC
      | OnlyGhci -- ^ The flag only affects the interactive GHC
      | AllModes -- ^ The flag affects multiple ghc modes
      | HiddenFlag -- ^ This flag should not be seen in cli completion
  
  data OptKind m                             -- Suppose the flag is -f
      = NoArg     (EwM m ())                 -- -f all by itself
      | HasArg    (String -> EwM m ())       -- -farg or -f arg
      | SepArg    (String -> EwM m ())       -- -f arg
      | Prefix    (String -> EwM m ())       -- -farg
      | OptPrefix (String -> EwM m ())       -- -f or -farg (i.e. the arg is optional)
      | OptIntSuffix (Maybe Int -> EwM m ()) -- -f or -f=n; pass n to fn
      | IntSuffix (Int -> EwM m ())          -- -f or -f=n; pass n to fn
      | FloatSuffix (Float -> EwM m ())      -- -f or -f=n; pass n to fn
      | PassFlag  (String -> EwM m ())       -- -f; pass "-f" fn
      | AnySuffix (String -> EwM m ())       -- -f or -farg; pass entire "-farg" to fn
      | PrefixPred    (String -> Bool) (String -> EwM m ())
      | AnySuffixPred (String -> Bool) (String -> EwM m ())
  
  
  --------------------------------------------------------
  --         The EwM monad
  --------------------------------------------------------
  
  type Err   = Located String
  type Warn  = Located String
  type Errs  = Bag Err
  type Warns = Bag Warn
  
  -- EwM ("errors and warnings monad") is a monad
  -- transformer for m that adds an (err, warn) state
  newtype EwM m a = EwM { unEwM :: Located String -- Current parse arg
                                -> Errs -> Warns
                                -> m (Errs, Warns, a) }
  
  instance Monad m => Functor (EwM m) where
      fmap = liftM
  
  instance Monad m => Applicative (EwM m) where
      pure = return
      (<*>) = ap
  
  instance Monad m => Monad (EwM m) where
      (EwM f) >>= k = EwM (\l e w -> do (e', w', r) <- f l e w
                                        unEwM (k r) l e' w')
      return v = EwM (\_ e w -> return (e, w, v))
  
  runEwM :: EwM m a -> m (Errs, Warns, a)
  runEwM action = unEwM action (panic "processArgs: no arg yet") emptyBag emptyBag
  
  setArg :: Monad m => Located String -> EwM m () -> EwM m ()
  setArg l (EwM f) = EwM (\_ es ws -> f l es ws)
  
  addErr :: Monad m => String -> EwM m ()
  addErr e = EwM (\(L loc _) es ws -> return (es `snocBag` L loc e, ws, ()))
  
  addWarn :: Monad m => String -> EwM m ()
  addWarn msg = EwM (\(L loc _) es ws -> return (es, ws `snocBag` L loc msg, ()))
  
  deprecate :: Monad m => String -> EwM m ()
  deprecate s = do
      arg <- getArg
      addWarn (arg ++ " is deprecated: " ++ s)
  
  getArg :: Monad m => EwM m String
  getArg = EwM (\(L _ arg) es ws -> return (es, ws, arg))
  
  getCurLoc :: Monad m => EwM m SrcSpan
  getCurLoc = EwM (\(L loc _) es ws -> return (es, ws, loc))
  
  liftEwM :: Monad m => m a -> EwM m a
  liftEwM action = EwM (\_ es ws -> do { r <- action; return (es, ws, r) })
  
  
  --------------------------------------------------------
  -- A state monad for use in the command-line parser
  --------------------------------------------------------
  
  -- (CmdLineP s) typically instantiates the 'm' in (EwM m) and (OptKind m)
  newtype CmdLineP s a = CmdLineP { runCmdLine :: s -> (a, s) }
  
  instance Functor (CmdLineP s) where
      fmap = liftM
  
  instance Applicative (CmdLineP s) where
      pure = return
      (<*>) = ap
  
  instance Monad (CmdLineP s) where
      m >>= k = CmdLineP $ \s ->
                    let (a, s') = runCmdLine m s
                    in runCmdLine (k a) s'
  
      return a = CmdLineP $ \s -> (a, s)
  
  getCmdLineState :: CmdLineP s s
  getCmdLineState   = CmdLineP $ \s -> (s,s)
  putCmdLineState :: s -> CmdLineP s ()
  putCmdLineState s = CmdLineP $ \_ -> ((),s)
  
  
  --------------------------------------------------------
  --         Processing arguments
  --------------------------------------------------------
  
  processArgs :: Monad m
              => [Flag m]               -- cmdline parser spec
              -> [Located String]       -- args
              -> m ( [Located String],  -- spare args
                     [Located String],  -- errors
                     [Located String] ) -- warnings
  processArgs spec args = do
      (errs, warns, spare) <- runEwM action
      return (spare, bagToList errs, bagToList warns)
    where
      action = process args []
  
      -- process :: [Located String] -> [Located String] -> EwM m [Located String]
      process [] spare = return (reverse spare)
  
      process (locArg@(L _ ('-' : arg)) : args) spare =
          case findArg spec arg of
              Just (rest, opt_kind) ->
                  case processOneArg opt_kind rest arg args of
                      Left err ->
                          let b = process args spare
                          in (setArg locArg $ addErr err) >> b
  
                      Right (action,rest) ->
                          let b = process rest spare
                          in (setArg locArg $ action) >> b
  
              Nothing -> process args (locArg : spare)
  
      process (arg : args) spare = process args (arg : spare)
  
  
  processOneArg :: OptKind m -> String -> String -> [Located String]
                -> Either String (EwM m (), [Located String])
  processOneArg opt_kind rest arg args
    = let dash_arg = '-' : arg
          rest_no_eq = dropEq rest
      in case opt_kind of
          NoArg  a -> ASSERT(null rest) Right (a, args)
  
          HasArg f | notNull rest_no_eq -> Right (f rest_no_eq, args)
                   | otherwise -> case args of
                                      []               -> missingArgErr dash_arg
                                      (L _ arg1:args1) -> Right (f arg1, args1)
  
          -- See Trac #9776
          SepArg f -> case args of
                          []               -> missingArgErr dash_arg
                          (L _ arg1:args1) -> Right (f arg1, args1)
  
          Prefix f | notNull rest_no_eq -> Right (f rest_no_eq, args)
                   | otherwise          -> unknownFlagErr dash_arg
  
          PrefixPred _ f | notNull rest_no_eq -> Right (f rest_no_eq, args)
                         | otherwise          -> unknownFlagErr dash_arg
  
          PassFlag f  | notNull rest -> unknownFlagErr dash_arg
                      | otherwise    -> Right (f dash_arg, args)
  
          OptIntSuffix f | null rest                     -> Right (f Nothing,  args)
                         | Just n <- parseInt rest_no_eq -> Right (f (Just n), args)
                         | otherwise -> Left ("malformed integer argument in " ++ dash_arg)
  
          IntSuffix f | Just n <- parseInt rest_no_eq -> Right (f n, args)
                      | otherwise -> Left ("malformed integer argument in " ++ dash_arg)
  
          FloatSuffix f | Just n <- parseFloat rest_no_eq -> Right (f n, args)
                        | otherwise -> Left ("malformed float argument in " ++ dash_arg)
  
          OptPrefix f       -> Right (f rest_no_eq, args)
          AnySuffix f       -> Right (f dash_arg, args)
          AnySuffixPred _ f -> Right (f dash_arg, args)
  
  findArg :: [Flag m] -> String -> Maybe (String, OptKind m)
  findArg spec arg =
      case sortBy (compare `on` (length . fst)) -- prefer longest matching flag
             [ (removeSpaces rest, optKind)
             | flag <- spec,
               let optKind  = flagOptKind flag,
               Just rest <- [stripPrefix (flagName flag) arg],
               arg_ok optKind rest arg ]
      of
          []      -> Nothing
          (one:_) -> Just one
  
  arg_ok :: OptKind t -> [Char] -> String -> Bool
  arg_ok (NoArg           _)  rest _   = null rest
  arg_ok (HasArg          _)  _    _   = True
  arg_ok (SepArg          _)  rest _   = null rest
  arg_ok (Prefix          _)  rest _   = notNull rest
  arg_ok (PrefixPred p    _)  rest _   = notNull rest && p (dropEq rest)
  arg_ok (OptIntSuffix    _)  _    _   = True
  arg_ok (IntSuffix       _)  _    _   = True
  arg_ok (FloatSuffix     _)  _    _   = True
  arg_ok (OptPrefix       _)  _    _   = True
  arg_ok (PassFlag        _)  rest _   = null rest
  arg_ok (AnySuffix       _)  _    _   = True
  arg_ok (AnySuffixPred p _)  _    arg = p arg
  
  -- | Parse an Int
  --
  -- Looks for "433" or "=342", with no trailing gubbins
  --   * n or =n      => Just n
  --   * gibberish    => Nothing
  parseInt :: String -> Maybe Int
  parseInt s = case reads s of
                   ((n,""):_) -> Just n
                   _          -> Nothing
  
  parseFloat :: String -> Maybe Float
  parseFloat s = case reads s of
                     ((n,""):_) -> Just n
                     _          -> Nothing
  
  -- | Discards a leading equals sign
  dropEq :: String -> String
  dropEq ('=' : s) = s
  dropEq s         = s
  
  unknownFlagErr :: String -> Either String a
  unknownFlagErr f = Left ("unrecognised flag: " ++ f)
  
  missingArgErr :: String -> Either String a
  missingArgErr f = Left ("missing argument for flag: " ++ f)
  
  --------------------------------------------------------
  -- Utils
  --------------------------------------------------------
  
  
  -- See Note [Handling errors when parsing flags]
  errorsToGhcException :: [(String,    -- Location
                            String)]   -- Error
                       -> GhcException
  errorsToGhcException errs =
      UsageError $ intercalate "\n" $ [ l ++ ": " ++ e | (l, e) <- errs ]
  
  {- Note [Handling errors when parsing commandline flags]
  
  Parsing of static and mode flags happens before any session is started, i.e.,
  before the first call to 'GHC.withGhc'. Therefore, to report errors for
  invalid usage of these two types of flags, we can not call any function that
  needs DynFlags, as there are no DynFlags available yet (unsafeGlobalDynFlags
  is not set either). So we always print "on the commandline" as the location,
  which is true except for Api users, which is probably ok.
  
  When reporting errors for invalid usage of dynamic flags we /can/ make use of
  DynFlags, and we do so explicitly in DynFlags.parseDynamicFlagsFull.
  
  Before, we called unsafeGlobalDynFlags when an invalid (combination of)
  flag(s) was given on the commandline, resulting in panics (#9963).
  -}
  