repline-0.3.0.0: examples/Simple.hs

module Main (main, repl) where

import Control.Monad.Trans
import Data.List (isPrefixOf)
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

-- 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

-- Commands
help :: [String] -> Repl ()
help args = liftIO $ print $ "Help: " ++ show args

say :: [String] -> Repl ()
say args = do
  _ <- liftIO $ callCommand $ "cowsay" ++ " " ++ (unwords args)
  return ()

opts :: [(String, [String] -> Repl ())]
opts =
  [ ("help", help), -- :help
    ("say", say) -- :say
  ]

ini :: Repl ()
ini = liftIO $ putStrLn "Welcome!"

repl :: IO ()
repl = evalRepl (pure ">>> ") cmd opts (Just ':') (Word0 completer) ini

main :: IO ()
main = pure ()