ivo/app/Main.hs

19 lines
471 B
Haskell

{-# LANGUAGE LambdaCase #-}
module Main where
import Control.Monad (forever)
import LambdaCalculus.Expression (lazyEval)
import LambdaCalculus.Parser (parseExpression)
import System.IO (hFlush, stdout)
prompt :: String -> IO String
prompt text = do
putStr text
hFlush stdout
getLine
main :: IO ()
main = forever $ parseExpression <$> prompt ">> " >>= \case
Left parseError -> putStrLn $ "Parse error: " ++ show parseError
Right expr -> print $ lazyEval expr