Implement basic interpreted language

src/Main.hs

@@ -1,4 +1,30 @@
+{-# LANGUAGE LambdaCase #-}
 module Main where
 
+import           Control.Monad.Except (runExcept)
+import           Grammar.Par          (myLexer, pProgram)
+import           Interpreter          (interpret)
+import           System.Environment   (getArgs)
+import           System.Exit          (exitFailure, exitSuccess)
+
 main :: IO ()
-main = putStrLn "Hello, Haskell!"
+main = getArgs >>= \case
+  []    -> print "Required file path missing"
+  (x:_) -> do
+    file <- readFile x
+    case pProgram (myLexer file) of
+      Left err -> do
+       putStrLn "SYNTAX ERROR"
+       putStrLn err
+       exitFailure
+      Right prg -> case runExcept $ interpret prg of
+        Left err -> do
+          putStrLn "INTERPRETER ERROR"
+          putStrLn err
+          exitFailure
+        Right i -> do
+          print i
+          exitSuccess
+
+
+