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module Main (main, repl) where
import Control.Monad.Trans
import Data.List (isPrefixOf)
import Data.Monoid
import System.Console.Repline
import System.Process (callCommand)
type Repl a = HaskelineT IO a
-- Evaluation : handle each line user inputs
cmd :: String -> Repl ()
cmd input = liftIO $ print input
-- Commands
help :: [String] -> Repl ()
help args = liftIO $ print $ "Help: " ++ show args
say :: String -> Repl ()
say args = do
_ <- liftIO $ callCommand $ "cowsay" ++ " " ++ args
return ()
load :: FilePath -> Repl ()
load args = do
contents <- liftIO $ readFile args
liftIO $ putStrLn contents
-- Options
opts :: [(String, String -> Repl ())]
opts =
[ ("help", help . words), -- :help
("load", load), -- :load
("say", say) -- :say
]
-- Tab Completion: return a completion for partial words entered
completer :: Monad m => WordCompleter m
completer n = do
let names = ["kirk", "spock", "mccoy"]
return $ filter (isPrefixOf n) names
-- Completer
defaultMatcher :: (MonadIO m) => [([Char], CompletionFunc m)]
defaultMatcher =
[ -- Commands
(":load", fileCompleter),
(":help", wordCompleter completer)
]
byWord :: Monad m => WordCompleter m
byWord n = do
let names = fmap ((":" <>) . fst) opts
return $ filter (isPrefixOf n) names
-- Initialiser function
ini :: Repl ()
ini = liftIO $ putStrLn "Welcome!"
-- Finaliser function
final :: Repl ExitDecision
final = do
liftIO $ putStrLn "Goodbye!"
return Exit
customBanner :: MultiLine -> Repl String
customBanner SingleLine = pure ">>> "
customBanner MultiLine = pure "| "
repl :: IO ()
repl =
evalReplOpts $
ReplOpts
{ banner = customBanner,
command = cmd,
options = opts,
prefix = Just ':',
multilineCommand = Just "paste",
tabComplete = (Prefix (wordCompleter byWord) defaultMatcher),
initialiser = ini,
finaliser = final
}
main :: IO ()
main = pure ()
|
