A bit

app/Main.hs

@@ -1,5 +1,11 @@
+{-# LANGUAGE LambdaCase #-}
 module Main where
 
+import Sudoku
+import System.Environment (getArgs)
+
+
 main :: IO ()
-main = do
-  putStrLn "Hello, Haskell!"
+main = getArgs >>= \case
+  [filename] -> readFile filename >>= print . parseStringToGrid
+  _ -> error "Usage: Estinen filename"