-- Hoogle documentation, generated by Haddock -- See Hoogle, http://www.haskell.org/hoogle/ -- | Simple command line argument parsing -- @package getopt-generics @version 0.8 -- | getopt-generics tries to make it very simple to create -- command line argument parsers. An introductory example can be found in -- the README. module System.Console.GetOpt.Generics -- | Parses command line arguments (gotten from withArgs) and -- returns the parsed value. This function should be enough for simple -- use-cases. -- -- May throw the following exceptions: -- -- getArguments :: (Generic a, HasDatatypeInfo a, All2 Option (Code a)) => IO a -- | Like getArguments but allows you to pass in Modifiers. modifiedGetArguments :: (Generic a, HasDatatypeInfo a, All2 Option (Code a)) => [Modifier] -> IO a -- | Pure variant of getArguments. -- -- Does not throw any exceptions. parseArguments :: (Generic a, HasDatatypeInfo a, All2 Option (Code a)) => String -> [Modifier] -> [String] -> Result a -- | Type to wrap results from the pure parsing functions. data Result a -- | The CLI was used correctly and a value of type a was -- successfully constructed. Success :: a -> Result a -- | The CLI was used incorrectly. The Result contains a list of -- error messages. -- -- It can also happen that the data type you're trying to use isn't -- supported. See the README for details. Errors :: [String] -> Result a -- | The CLI was used with --help. The Result contains the -- help message. OutputAndExit :: String -> Result a -- | Modifiers can be used to customize the command line parser. data Modifier -- | AddShortOption fieldName c adds the Char c as -- a short option for the field addressed by fieldName. AddShortOption :: String -> Char -> Modifier -- | RenameOption fieldName customName renames the option -- generated through the fieldName by customName. RenameOption :: String -> String -> Modifier -- | RenameOptions f renames all options with the given functions. -- In case the function returns Nothing the original field name -- is used. -- -- Can be used together with stripPrefix. RenameOptions :: (String -> Maybe String) -> Modifier -- | UseForPositionalArguments fieldName argumentType fills the -- field addressed by fieldName with the positional arguments -- (i.e. arguments that don't correspond to a flag). The field has to -- have type [String]. -- -- argumentType is used as the type of the positional arguments -- in the help output. UseForPositionalArguments :: String -> String -> Modifier -- | AddOptionHelp fieldName helpText adds a help text for the -- option fieldName. AddOptionHelp :: String -> String -> Modifier -- | AddVersionFlag version adds a --version flag. AddVersionFlag :: String -> Modifier -- | Derives AddShortOptions for all fields of the datatype that -- start with a unique character. deriveShortOptions :: (HasDatatypeInfo a, SingI (Code a)) => Proxy a -> [Modifier] -- | Type class for all allowed field types. -- -- If you want to use custom field types you should implement an -- instance Option YourCustomType containing implementations of -- argumentType and parseArgument (the minimal complete -- definition). For an example see the README. class Typeable a => Option a where _toOption = ReqArg parseAsFieldState (argumentType (Proxy :: Proxy a)) _emptyOption modifiers flagName = Unset ("missing option: --" ++ mkLongOption modifiers flagName ++ "=" ++ argumentType (Proxy :: Proxy a)) _accumulate _ x = x argumentType :: Option a => Proxy a -> String parseArgument :: Option a => String -> Maybe a _toOption :: Option a => ArgDescr (FieldState a) _emptyOption :: Option a => Modifiers -> FieldString -> FieldState a _accumulate :: Option a => a -> a -> a -- | The class of representable datatypes. -- -- The SOP approach to generic programming is based on viewing datatypes -- as a representation (Rep) built from the sum of products of its -- components. The components of are datatype are specified using the -- Code type family. -- -- The isomorphism between the original Haskell datatype and its -- representation is witnessed by the methods of this class, from -- and to. So for instances of this class, the following laws -- should (in general) hold: -- -- 
--   to . from === id :: a -> a
--   from . to === id :: Rep a -> Rep a
--
-- -- You typically don't define instances of this class by hand, but rather -- derive the class instance automatically. -- -- Option 1: Derive via the built-in GHC-generics. For this, you -- need to use the DeriveGeneric extension to first derive an -- instance of the Generic class from module GHC.Generics. -- With this, you can then give an empty instance for Generic, and -- the default definitions will just work. The pattern looks as follows: -- -- 
--   import qualified GHC.Generics as GHC
--   import Generics.SOP
--   
--   ...
--   
--   data T = ... deriving (GHC.Generic, ...)
--   
--   instance Generic T -- empty
--   instance HasDatatypeInfo T -- empty, if you want/need metadata
--
-- -- Option 2: Derive via Template Haskell. For this, you need to -- enable the TemplateHaskell extension. You can then use -- deriveGeneric from module Generics.SOP.TH to have the -- instance generated for you. The pattern looks as follows: -- -- 
--   import Generics.SOP
--   import Generics.SOP.TH
--   
--   ...
--   
--   data T = ...
--   
--   deriveGeneric ''T -- derives HasDatatypeInfo as well
--
-- -- Tradeoffs: Whether to use Option 1 or 2 is mainly a matter of -- personal taste. The version based on Template Haskell probably has -- less run-time overhead. -- -- Non-standard instances: It is possible to give Generic -- instances manually that deviate from the standard scheme, as long as -- at least -- -- 
--   to . from === id :: a -> a
--
-- -- still holds. class (SingI [[*]] (Code a), All [*] (SingI [*]) (Code a)) => Generic a where type family Code a :: [[*]] -- | A class of datatypes that have associated metadata. -- -- It is possible to use the sum-of-products approach to generic -- programming without metadata. If you need metadata in a function, an -- additional constraint on this class is in order. -- -- You typically don't define instances of this class by hand, but rather -- derive the class instance automatically. See the documentation of -- Generic for the options. class HasDatatypeInfo a -- | Require a constraint for every element of a list of lists. -- -- If you have a datatype that is indexed over a type-level list of -- lists, then you can use All2 to indicate that all elements of -- the innert lists must satisfy a given constraint. -- -- Example: The constraint -- -- 
--   All2 Eq '[ '[ Int ], '[ Bool, Char ] ]
--
-- -- is equivalent to the constraint -- -- 
--   (Eq Int, Eq Bool, Eq Char)
--
-- -- Example: A type signature such as -- -- 
--   f :: All2 Eq xss => SOP I xs -> ...
--
-- -- means that f can assume that all elements of the sum of -- product satisfy Eq. -- | The code of a datatype. -- -- This is a list of lists of its components. The outer list contains one -- element per constructor. The inner list contains one element per -- constructor argument (field). -- -- Example: The datatype -- -- 
--   data Tree = Leaf Int | Node Tree Tree
--
-- -- is supposed to have the following code: -- -- 
--   type instance Code (Tree a) =
--     '[ '[ Int ]
--      , '[ Tree, Tree ]
--      ]
--
-- | A concrete, poly-kinded proxy type data Proxy (t :: k) :: k -> * Proxy :: Proxy instance [overlap ok] Typeable FieldState instance [overlap ok] Eq OutputInfoFlag instance [overlap ok] Ord OutputInfoFlag instance [overlap ok] Option Double instance [overlap ok] Option Float instance [overlap ok] Option Integer instance [overlap ok] Option Int instance [overlap ok] Option String instance [overlap ok] Option Bool instance [overlap ok] Option a => Option (Maybe a) instance [overlap ok] Option a => Option [a]