Command.hs

{-# LANGUAGE FlexibleInstances, TypeSynonymInstances #-}
module UI.Command.Command (
	Command (..),
        defCmd
) where

import Data.Default

import Control.Monad.Trans (liftIO)

import UI.Command.App (App)

------------------------------------------------------------
-- Command class
--

-- | It is often simpler to use the default implementation of Command, and
-- override it with the details you choose to use.
-- For example, an implementation of the ''hello world'' command:
--
-- > world = def {
-- >         cmdName = "world",
-- >         cmdHandler = worldHandler,
-- >         cmdCategory = "Greetings",
-- >         cmdShortDesc = "An implementation of the standard software greeting."
-- > }
-- >
-- > worldHandler = liftIO $ putStrLn "Hello world!"
--
data (Default config) => Command config = Command {
    -- | Name of the cmdcommand
    cmdName :: String,

    -- | Handler
    cmdHandler :: App config (),

    -- | Category in this program's documentation
    cmdCategory :: String,

    -- | Synopsis
    cmdSynopsis :: String,

    -- | Short description
    cmdShortDesc :: String,

    -- | [(example description, args)]
    cmdExamples :: [(String, String)]
}

instance (Default config) => Default (App config ()) where
    def = liftIO $ putStrLn "Unimplemented command"

instance (Default config) => Default (Command config) where
    def = Command "<Anonymous command>" def def def def def

defCmd :: Command ()
defCmd = Command "<Anonymous command>" def def def def def