{-# LANGUAGE Rank2Types #-} module Options.Applicative.Common ( -- * Option parsers -- -- | A 'Parser' is composed of a list of options. Several kinds of options -- are supported: -- -- * Flags: simple no-argument options. When a flag is encountered on the -- command line, its value is returned. -- -- * Options: options with an argument. An option can define a /reader/, -- which converts its argument from String to the desired value, or throws a -- parse error if the argument does not validate correctly. -- -- * Arguments: positional arguments, validated in the same way as option -- arguments. -- -- * Commands. A command defines a completely independent sub-parser. When a -- command is encountered, the whole command line is passed to the -- corresponding parser. -- Parser, liftOpt, showOption, -- * Program descriptions -- -- A 'ParserInfo' describes a command line program, used to generate a help -- screen. Two help modes are supported: brief and full. In brief mode, only -- an option and argument summary is displayed, while in full mode each -- available option and command, including hidden ones, is described. -- -- A basic 'ParserInfo' with default values for fields can be created using -- the 'info' function. -- -- A 'ParserPrefs' contains general preferences for all command-line -- options, and can be built with the 'prefs' function. ParserInfo(..), ParserPrefs(..), -- * Running parsers runParserInfo, runParserFully, runParser, evalParser, -- * Low-level utilities mapParser, treeMapParser, optionNames ) where import Control.Applicative (pure, (<*>), (<$>), (<|>), (<$)) import Control.Monad (guard, mzero, msum, when, liftM, MonadPlus) import Control.Monad.Trans.Class (lift) import Control.Monad.Trans.State (StateT(..), get, put, runStateT) import Data.List (isPrefixOf) import Data.Maybe (maybeToList, isJust, isNothing) import Data.Monoid (Monoid(..)) import Options.Applicative.Internal import Options.Applicative.Types showOption :: OptName -> String showOption (OptLong n) = "--" ++ n showOption (OptShort n) = '-' : [n] optionNames :: OptReader a -> [OptName] optionNames (OptReader names _ _) = names optionNames (FlagReader names _) = names optionNames _ = [] isOptionPrefix :: OptName -> OptName -> Bool isOptionPrefix (OptShort x) (OptShort y) = x == y isOptionPrefix (OptLong x) (OptLong y) = x `isPrefixOf` y isOptionPrefix _ _ = False -- | Create a parser composed of a single option. liftOpt :: Option a -> Parser a liftOpt = OptP data MatchResult = NoMatch | Match (Maybe String) instance Monoid MatchResult where mempty = NoMatch mappend m@(Match _) _ = m mappend _ m = m argMatches :: MonadP m => OptReader a -> String -> Maybe (StateT Args m a) argMatches opt arg = case opt of ArgReader rdr -> do result <- crReader rdr arg Just $ return result CmdReader _ f -> flip fmap (f arg) $ \subp -> StateT $ \args -> do setContext (Just arg) subp prefs <- getPrefs let runSubparser | prefBacktrack prefs = \i a -> do runParser (getPolicy i) (infoParser i) a | otherwise = \i a -> (,) <$> runParserInfo i a <*> pure [] runSubparser subp args _ -> Nothing optMatches :: MonadP m => Bool -> OptReader a -> OptWord -> Maybe (StateT Args m a) optMatches disambiguate opt (OptWord arg1 val) = case opt of OptReader names rdr no_arg_err -> do guard $ has_name arg1 names Just $ do args <- get let mb_args = uncons $ maybeToList val ++ args let missing_arg = lift $ missingArgP no_arg_err (crCompleter rdr) (arg', args') <- maybe missing_arg return mb_args put args' case runReadM (crReader rdr arg') of Left e -> lift $ errorFor arg1 e Right r -> return r FlagReader names x -> do guard $ has_name arg1 names guard $ isNothing val Just $ return x _ -> Nothing where errorFor name (ErrorMsg msg) = errorP (ErrorMsg ("option " ++ showOption name ++ ": " ++ msg)) errorFor _ e = errorP e has_name a | disambiguate = any (isOptionPrefix a) | otherwise = elem a isArg :: OptReader a -> Bool isArg (ArgReader _) = True isArg _ = False data OptWord = OptWord OptName (Maybe String) parseWord :: String -> Maybe OptWord parseWord ('-' : '-' : w) = Just $ let (opt, arg) = case span (/= '=') w of (_, "") -> (w, Nothing) (w', _ : rest) -> (w', Just rest) in OptWord (OptLong opt) arg parseWord ('-' : w) = case w of [] -> Nothing (a : rest) -> Just $ let arg = rest <$ guard (not (null rest)) in OptWord (OptShort a) arg parseWord _ = Nothing searchParser :: Monad m => (forall r . Option r -> NondetT m r) -> Parser a -> NondetT m (Parser a) searchParser _ (NilP _) = mzero searchParser f (OptP opt) = liftM pure (f opt) searchParser f (MultP p1 p2) = foldr1 (<!>) [ do p1' <- searchParser f p1 return (p1' <*> p2) , do p2' <- searchParser f p2 return (p1 <*> p2') ] searchParser f (AltP p1 p2) = msum [ searchParser f p1 , searchParser f p2 ] searchParser f (BindP p k) = do p' <- searchParser f p x <- hoistMaybe (evalParser p') return (k x) searchOpt :: MonadP m => ParserPrefs -> OptWord -> Parser a -> NondetT (StateT Args m) (Parser a) searchOpt pprefs w = searchParser $ \opt -> do let disambiguate = prefDisambiguate pprefs && optVisibility opt > Internal case optMatches disambiguate (optMain opt) w of Just matcher -> lift matcher Nothing -> mzero searchArg :: MonadP m => String -> Parser a -> NondetT (StateT Args m) (Parser a) searchArg arg = searchParser $ \opt -> do when (isArg (optMain opt)) cut case argMatches (optMain opt) arg of Just matcher -> lift matcher Nothing -> mzero stepParser :: MonadP m => ParserPrefs -> ArgPolicy -> String -> Parser a -> NondetT (StateT Args m) (Parser a) stepParser pprefs SkipOpts arg p = case parseWord arg of Just w -> searchOpt pprefs w p Nothing -> searchArg arg p stepParser pprefs AllowOpts arg p = msum [ searchArg arg p , do w <- hoistMaybe (parseWord arg) searchOpt pprefs w p ] -- | Apply a 'Parser' to a command line, and return a result and leftover -- arguments. This function returns an error if any parsing error occurs, or -- if any options are missing and don't have a default value. runParser :: MonadP m => ArgPolicy -> Parser a -> Args -> m (a, Args) runParser policy p args = case args of [] -> exitP p result ("--" : argt) -> runParser AllowOpts p argt (arg : argt) -> do prefs <- getPrefs (mp', args') <- do_step prefs arg argt case mp' of Nothing -> hoistMaybe result <|> parseError arg Just p' -> runParser policy p' args' where result = (,) <$> evalParser p <*> pure args do_step prefs arg argt = (`runStateT` argt) . disamb (not (prefDisambiguate prefs)) $ stepParser prefs policy arg p parseError :: MonadP m => String -> m a parseError arg = errorP . ErrorMsg $ msg where msg = case arg of ('-':_) -> "Invalid option `" ++ arg ++ "'" _ -> "Invalid argument `" ++ arg ++ "'" getPolicy :: ParserInfo a -> ArgPolicy getPolicy i = if infoIntersperse i then SkipOpts else AllowOpts runParserInfo :: MonadP m => ParserInfo a -> Args -> m a runParserInfo i args = runParserFully (getPolicy i) (infoParser i) args runParserFully :: MonadP m => ArgPolicy -> Parser a -> Args -> m a runParserFully policy p args = do (r, args') <- runParser policy p args guard $ null args' return r -- | The default value of a 'Parser'. This function returns an error if any of -- the options don't have a default value. evalParser :: Parser a -> Maybe a evalParser (NilP r) = r evalParser (OptP _) = Nothing evalParser (MultP p1 p2) = evalParser p1 <*> evalParser p2 evalParser (AltP p1 p2) = evalParser p1 <|> evalParser p2 evalParser (BindP p k) = evalParser p >>= evalParser . k -- | Map a polymorphic function over all the options of a parser, and collect -- the results in a list. mapParser :: (forall x. OptHelpInfo -> Option x -> b) -> Parser a -> [b] mapParser f = flatten . treeMapParser f where flatten (Leaf x) = [x] flatten (MultNode xs) = xs >>= flatten flatten (AltNode xs) = xs >>= flatten -- | Like 'mapParser', but collect the results in a tree structure. treeMapParser :: (forall x . OptHelpInfo -> Option x -> b) -> Parser a -> OptTree b treeMapParser g = simplify . go False False g where has_default :: Parser a -> Bool has_default p = isJust (evalParser p) go :: Bool -> Bool -> (forall x . OptHelpInfo -> Option x -> b) -> Parser a -> OptTree b go _ _ _ (NilP _) = MultNode [] go m d f (OptP opt) | optVisibility opt > Internal = Leaf (f (OptHelpInfo m d) opt) | otherwise = MultNode [] go m d f (MultP p1 p2) = MultNode [go m d f p1, go m d f p2] go m d f (AltP p1 p2) = AltNode [go m d' f p1, go m d' f p2] where d' = d || has_default p1 || has_default p2 go _ d f (BindP p _) = go True d f p simplify :: OptTree a -> OptTree a simplify (Leaf x) = Leaf x simplify (MultNode xs) = case concatMap (remove_mult . simplify) xs of [x] -> x xs' -> MultNode xs' where remove_mult (MultNode ts) = ts remove_mult t = [t] simplify (AltNode xs) = case concatMap (remove_alt . simplify) xs of [] -> MultNode [] [x] -> x xs' -> AltNode xs' where remove_alt (AltNode ts) = ts remove_alt (MultNode []) = [] remove_alt t = [t]