From 1b8680004eeef97782cf95746f0da4e5acc67cc9 Mon Sep 17 00:00:00 2001
From: Joscha <joscha@plugh.de>
Date: Wed, 13 Nov 2019 07:58:41 +0000
Subject: [PATCH] Create utility function for loading and parsing files

---
 app/MimaAsm/Main.hs | 14 +++++---------
 src/Mima/IO.hs      | 17 +++++++++++++++++
 2 files changed, 22 insertions(+), 9 deletions(-)
 create mode 100644 src/Mima/IO.hs

diff --git a/app/MimaAsm/Main.hs b/app/MimaAsm/Main.hs
index 77d6656..9550948 100644
--- a/app/MimaAsm/Main.hs
+++ b/app/MimaAsm/Main.hs
@@ -1,10 +1,9 @@
 module Main where
 
-import qualified Data.Text.IO as T
 import           Options.Applicative
-import           Text.Megaparsec
 
 import           Mima.Assembler.Parser
+import           Mima.IO
 import           Mima.Load
 
 data Settings = Settings
@@ -33,13 +32,10 @@ main = do
   settings <- execParser opts
 
   putStrLn $ "Loading assembly file at " ++ infile settings
-  asm <- T.readFile (infile settings)
-
-  putStrLn "Parsing assembly"
-  let parsed = parse parseState (infile settings) asm
-  case parsed of
-    Left errorBundle      -> putStrLn $ errorBundlePretty errorBundle
-    Right (state, _) -> do
+  asm <- parseFile parseState (infile settings)
+  case asm of
+    Nothing -> pure ()
+    Just (state, _) -> do
       putStrLn "Parsing successful"
       putStrLn $ "Writing result to " ++ outfile settings
       saveStateToFile (outfile settings) state
diff --git a/src/Mima/IO.hs b/src/Mima/IO.hs
new file mode 100644
index 0000000..589eb8b
--- /dev/null
+++ b/src/Mima/IO.hs
@@ -0,0 +1,17 @@
+module Mima.IO
+  ( parseFile
+  ) where
+
+import qualified Data.Text.IO as T
+import           Text.Megaparsec
+
+import           Mima.Parser.Common
+
+parseFile :: Parser a -> FilePath -> IO (Maybe a)
+parseFile parser filepath = do
+  content <- T.readFile filepath
+  case parse parser filepath content of
+    Right a           -> pure $ Just a
+    Left errorBundle  -> do
+      putStrLn $ errorBundlePretty errorBundle
+      pure Nothing