Add command line argument parsing

README.md

@@ -52,12 +52,13 @@ I recommend using VSCodium, which is preconfigured to have syntax highlighting a
 - https://danieljharvey.github.io/posts/2023-02-08-llvm-compiler-part-1.html (for help using llvm-hs-pure)
 - https://gh.sudoer.ch/danieljharvey/mimsa/blob/trunk/llvm-calc/src/Calc/Compile/ToLLVM.hs (source code for above resource)
 - https://9to5tutorial.com/homebrew-compiler-made-with-haskell-llvm-configuration (for help using llvm-hs-pure)
+- https://blog.ocharles.org.uk/blog/posts/2012-12-17-24-days-of-hackage-optparse-applicative.html (for help parsing command line arguments with optparse-applicative)
 
 ### Tools
 
 - Language: Haskell
-- Haskell tools: GHCup, Stack, Cabal, GHC 9.2
-- Libraries: megaparsec, parser-combinators, text, process, llvm-hs 15, llvm-hs-pure 15,
+- Haskell/management tools: GHCup, Stack, Cabal, GHC 9.2, Nix
+- Libraries: See `package.yaml`
 - Dependencies: llvm 15, clang 15
 - IDE: VSCodium
 - Git platform: Forgejo

package.yaml

@@ -14,6 +14,7 @@ dependencies:
   - bytestring
   - string-conversions
   - transformers
+  - optparse-applicative >= 0.17 && < 1
 tested-with: GHC == 9.2.8
 category: Compilers/Interpreters
 

really-bad-compiler-in-haskell.cabal

@@ -33,6 +33,7 @@ executable really-bad-compiler-in-haskell
     , llvm-hs-pure ==15.*
     , megaparsec >=9.0.1 && <10
     , mtl
+    , optparse-applicative >=0.17 && <1
     , parser-combinators
     , process
     , string-conversions

src/Main.hs

@@ -7,12 +7,19 @@ import Data.ByteString.Char8 qualified as B
 import Data.Text.IO qualified as T
 import Main.LLVMGen
 import Main.Parser.Megaparsec
+import Options.Applicative
 import System.Environment
 import System.Process (callCommand)
 
-main :: IO ()
-main = do
-  fileName <- head <$> getArgs
+data Opt = Opt
+  { filePath :: String,
+    showLLVM :: Bool,
+    showDebug :: Bool
+  }
+
+run :: Opt -> IO ()
+run opts = do
+  let fileName = filePath opts
   contents <- T.readFile fileName
   T.putStrLn "- Generating LLVM to './a.out.ll'..."
   result <- (llvmGen . parse) contents
@@ -20,3 +27,21 @@ main = do
   T.putStrLn "- Compiling to executable './a.out'..."
   callCommand "clang a.out.ll"
   T.putStrLn "- Done."
+
+main :: IO ()
+main = execParser opts >>= run
+  where
+    parser =
+      Opt
+        <$> argument str (metavar "FILE_PATH")
+        <*> switch
+          ( short 'l'
+              <> long "showLLVM"
+              <> help "Create <file>.ll with LLVM used to compile the binary"
+          )
+        <*> switch
+          ( short 'd'
+              <> long "showDebug"
+              <> help "Show debug output"
+          )
+    opts = info parser mempty