module Main where

import Control.Monad
import Data.Either
import System.Environment
import System.Exit

import Check
import Codegen
import Parser
import PShow


fromLeft :: Either a b -> a
fromLeft (Left a) = a
fromLeft (Right _) = error "Either is not a Left"

fromRight :: Either a b -> b
fromRight (Right b) = b
fromRight (Left _) = error "Either is not a Right"

dieShow :: (Show a) => a -> IO ()
dieShow = die . show


main :: IO ()
main = do
    args <- getArgs
    when (length args /= 1) $ die "Pass NL file name as a command-line parameter"

    let fname = args !! 0
    parseResult <- (\file -> parseProgram file fname) <$> readFile fname

    when (isLeft parseResult) $ dieShow $ fromLeft parseResult
    
    let ast = fromRight parseResult
    putStrLn $ pshow ast

    checked <- either die return $ checkProgram ast
    putStrLn "After checking:"
    putStrLn $ pshow checked

    llvmMod <- either die return $ codegen checked "Module" fname
    putStrLn "Module:"
    print llvmMod