Read expressions from file

app/Main.hs

@@ -1,21 +1,22 @@
 module Main (main) where
 
+import Control.Monad
 import Data.Either
 import Eval.Expression
 import Objects.Expression
 import Parser.Expression
 import System.Environment
+import System.IO
 import Text.Megaparsec
 
-parseResult :: ParseResult
-parseResult = parseExpr "2+3*4"
-
 getRight :: ParseResult -> Expr
 getRight (Right r) = r
 
-expr = getRight parseResult
-
-result = evalExpr expr
+getResult :: String -> Int
+getResult str = evalExpr (getRight (parseExpr str))
 
 main = do
-  print result
+  fileName <- fmap head getArgs
+  contents <- readFile fileName
+  let result = getResult contents
+  print result