-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | A modern command-line parser for Haskell.
--   
@package lambda-options
@version 0.1.0.0

module Text.LambdaOptions

-- | Class describing parseable values. Much like the <a>Read</a> class.
class Parseable a
parse :: Parseable a => String -> Maybe a

-- | An option keyword, such as <tt>"--help"</tt>
--   
--   NB: In the future, this will become a proper data type that contains a
--   list of aliases and help descriptions.
type Keyword = String

-- | The callback to be called for a successfully parsed option.
--   
--   This function (or value) can have any arity and ultimately returns a
--   value with type <tt>Monad m =&gt; m ()</tt>
--   
--   Each of the callback's arguments must have a type <tt>t</tt> which
--   implements <a>Parseable</a>.
--   
--   Example callbacks:
--   
--   <pre>
--   putStrLn "Option parsed!" :: IO ()
--   put :: String -&gt; State ()
--   \n -&gt; liftIO (print n) :: (MonadIO m) =&gt; Int -&gt; m ()
--   \n s f -&gt; lift (print (n, s, f)) :: (MonadTrans m) =&gt; Int -&gt; String -&gt; Float -&gt; m IO ()
--   </pre>
type OptionCallback m f = (Monad m, GetOpaqueParsers f, WrapCallback m f)

-- | A monad transformer for parsing options.
data Options m a

-- | Contains information about what went wrong during an unsuccessful
--   parse.
data OptionsError

-- | NB: In the future, there will be more informative constructors.
OptionsError :: OptionsError

-- | Adds the following option into the monadic context.
addOption :: OptionCallback m f => Keyword -> f -> Options m ()

-- | Tries to parse the supplied options against input arguments. If
--   successful, parsed option callbacks are executed.
runOptions :: Monad m => Options m a -> [String] -> m (Maybe OptionsError)
instance (Monad m, Functor m) => Applicative (Options m)
instance Functor m => Functor (Options m)
instance Monad m => Monad (Options m)
instance Monad m => MonadState (OptionsState m) (Options m)
instance MonadIO m => MonadIO (Options m)
instance Show OptionsError
instance MonadTrans Options
instance (Typeable a, WrapCallback m b) => WrapCallback m (a -> b)
instance WrapCallback m (m ())
instance Monad m => GetOpaqueParsers (m ())
instance (Parseable a, Typeable a, GetOpaqueParsers b) => GetOpaqueParsers (a -> b)
instance Parseable Float
instance Parseable String
instance Parseable Int