From c50d9e35dc25162427f0480db2ad8bdbb4a6f0b1 Mon Sep 17 00:00:00 2001
From: thepenguin <nor@acorneroftheweb.com>
Date: Wed, 26 Oct 2022 12:37:48 +0200
Subject: [PATCH] created an args system

---
 app/Main.hs | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/app/Main.hs b/app/Main.hs
index 75ad35c..1d1bd25 100644
--- a/app/Main.hs
+++ b/app/Main.hs
@@ -1,6 +1,29 @@
 module Main where
 
+import Control.Monad
 import System.Environment
+import System.Exit
+import Text.ParserCombinators.ReadP
+
+parse :: ReadP String -> String -> String
+parse rules = fst . last .readP_to_S rules
 
 main :: IO ()
-main = putStrLn =<< readFile =<< head <$> getArgs
+main = useArgs =<< ( parse argParse . unlines) <$> getArgs
+
+argParse :: ReadP String
+argParse =
+  string "-" >> (many1 (satisfy (/= ' ')))
+
+useArgs :: String -> IO a
+useArgs []       = exit
+useArgs ('h':_) = usage   >> exit
+useArgs ('v':_) = version >> exit
+useArgs (_:xs)   = useArgs xs
+
+usage :: IO ()
+usage   = putStrLn "Usage: \"PENDINGNAME\" [-hv] [file]"
+version :: IO ()
+version = putStrLn "\"PENDINGNAME\" 0.1"
+exit :: IO a
+exit    = exitWith ExitSuccess