{-# LANGUAGE LambdaCase #-}

module Main where

import Control.Monad.Trans.Except (runExceptT)
import Data.Text (Text)
import qualified Data.Text.IO as T
import System.Environment (getArgs)

import Language.Epsilon.Parser (parse)
import Language.Epsilon.Types (runEvalM)
import Language.Epsilon.Eval (eval)

main :: IO ()
main = getArgs >>= \case
  [] -> T.getContents >>= go "<stdin>"
  [x] -> T.readFile x >>= go x
  _ -> putStrLn "not sure what to do with these cli args"

go :: FilePath -> Text -> IO ()
go fp s =
  case parse fp s of
    Left pe -> print pe
    Right ast -> do
      runExceptT (runEvalM $ eval ast) >>= \case
        Left e -> print e
        Right res -> print res