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


-- | A modern command-line parser for Haskell.
--   
--   A modern command-line parser for Haskell.
@package lambda-options
@version 0.3.0.0

module Text.LambdaOptions

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

-- | An option keyword, such as <tt>"--help"</tt>
data Keyword
Keyword :: [String] -> String -> String -> Keyword

-- | All the aliases for this keyword.
kwNames :: Keyword -> [String]

-- | Text to describe the arguments to the option given by this keyword.
kwArgText :: Keyword -> String

-- | Text to describe the function of the option given by this keyword.
kwText :: Keyword -> String

-- | Describes the callback <tt>f</tt> to be called for a successfully
--   parsed option.
--   
--   The function (or value) <tt>f</tt> 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> and <a>Typeable</a>.
--   
--   Think of this as the following constraint synonym:
--   
--   <pre>
--   type OptionCallback m f = (Monad m, f ~ (Parseable t*, Typeable t*) =&gt; t0 -&gt; t1 -&gt; ... -&gt; tN -&gt; m ())
--   </pre>
--   
--   Example callbacks:
--   
--   <pre>
--   f0 = putStrLn "Option parsed!" :: IO ()
--   f1 = put :: String -&gt; State String ()
--   f2 n = liftIO (print n) :: (MonadIO m) =&gt; Int -&gt; m ()
--   f3 name year ratio = lift (print (name, year, ratio)) :: (MonadTrans m) =&gt; String -&gt; Int -&gt; Float -&gt; m IO ()
--   </pre>
type OptionCallback m f = (Monad m, GetOpaqueParsers f, WrapCallback m f)

-- | Adds the supplied option to the <tt>Options m ()</tt> context.
--   
--   If the keyword is matched and the types of the callback's parameters
--   can successfully be parsed, the callback is called with the parsed
--   arguments.
addOption :: OptionCallback m f => Keyword -> f -> Options m ()

-- | When used as a callback argument, this contains the help description
--   given by the added options.
--   
--   Example:
--   
--   <pre>
--   addOption (kw ["--help", "-h"]) $ \(HelpDescription desc) -&gt; do
--       putStrLn desc
--   </pre>
newtype HelpDescription
HelpDescription :: String -> HelpDescription
class ToKeyword a

-- | Convenience <a>Keyword</a> to build upon. Takes either a single alias
--   or a list of name aliases to start with. Use record syntax to set the
--   rest.
kw :: ToKeyword a => a -> Keyword

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

-- | Contains <tt>(error-message)</tt> <tt>(begin-args-index)</tt>
--   <tt>(end-args-index)</tt>
ParseFailed :: String -> Int -> Int -> OptionsError

-- | Tries to parse the supplied options against input arguments. If
--   successful, parsed option callbacks are executed. Otherwise
--   <b><i>none</i></b> of the callbacks are executed.
--   
--   Example:
--   
--   <pre>
--   import System.Environment
--   import Text.LambdaOptions
--   
--   options :: Options IO ()
--   options = do
--       addOption (kw "--help") $ do
--           putStrLn "--user NAME [AGE]"
--       addOption (kw "--user") $ \name -&gt; do
--           putStrLn $ "Name:" ++ name
--       addOption (kw "--user") $ \name age -&gt; do
--           putStrLn $ "Name:" ++ name ++ " Age:" ++ show (age :: Int)
--   
--   main :: IO ()
--   main = do
--       args &lt;- getArgs
--       mError &lt;- runOptions options args
--       case mError of
--           Just (ParseFailed msg _ _) -&gt; putStrLn msg
--           Nothing -&gt; return ()
--   </pre>
runOptions :: Monad m => Options m a -> [String] -> m (Maybe OptionsError)

-- | Class describing parseable values. Much like the <a>Read</a> class.
class Parseable a
parse :: Parseable a => [String] -> (Maybe a, Int)

-- | A simple wrapper over <tt>[a]</tt>. Used to avoid overlapping
--   instances for <tt>Parseable [a]</tt> and <tt>Parseable String</tt>
newtype List a
List :: [a] -> List a
instance Typeable List
instance Typeable HelpDescription
instance Show a => Show (List a)
instance Read a => Read (List a)
instance Eq a => Eq (List a)
instance Ord a => Ord (List a)
instance Show Keyword
instance Eq Keyword
instance Ord Keyword
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 Show FormattingConfig
instance Read FormattingConfig
instance Eq FormattingConfig
instance Ord FormattingConfig
instance MonadTrans Options
instance ToKeyword [String]
instance ToKeyword String
instance ToKeyword Keyword
instance IsString Keyword
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 HelpDescription
instance Parseable a => Parseable (List a)
instance Parseable a => Parseable (Maybe a)
instance Parseable Float
instance Parseable String
instance Parseable Int