Added CLI

1 files changed, 69 insertions, 5 deletions

diff --git a/src/Main.hs b/src/Main.hs
index 47fd883..8959329 100644
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -1,21 +1,85 @@
 module Main where
 
 import Compiler
+import Control.Monad (when)
 import Control.Monad.State (evalState)
 import qualified Data.Map as Map
+import Data.Maybe (fromMaybe)
 import Error (showErrorList, showParserError)
 import Lexer (scan)
 import Parser (parse, parseFromFile)
-import System.Exit (exitFailure)
+import System.Console.GetOpt
+import System.Environment (getProgName)
+import System.Environment.Blank (getArgs)
+import System.Exit (exitFailure, exitSuccess)
 import System.IO (hPutStr, hPutStrLn, stderr, stdout)
 
-main :: IO ()
-main = do
-  res <- parseFromFile (scan parse) "input"
+version = "0.1.0"
+
+data Options = Options
+  { optHelp :: Bool,
+    optVersion :: Bool
+  }
+
+defOptions =
+  Options
+    { optHelp = False,
+      optVersion = False
+    }
+
+options :: [OptDescr (Options -> Options)]
+options =
+  [ Option
+      ['h']
+      ["help"]
+      (NoArg (\opts -> opts {optHelp = True}))
+      "show help and exit",
+    Option
+      ['v']
+      ["version"]
+      (NoArg (\opts -> opts {optVersion = True}))
+      "output version and exit"
+  ]
+
+usage :: String -> [String] -> IO ()
+usage progName errs
+  | null errs = do
+      putStrLn helpText
+      exitSuccess
+  | otherwise = do
+      hPutStrLn stderr ("error: " ++ concat errs ++ "Try " ++ progName ++ " -h for more information.")
+      exitFailure
+  where
+    header =
+      "Usage: "
+        ++ progName
+        ++ " [OPTION...] file"
+    helpText =
+      usageInfo header options
+
+compileFile :: String -> IO ()
+compileFile filename = do
+  res <- parseFromFile (scan parse) filename
   case res of
     Left err -> hPutStrLn stderr (showParserError err) >> exitFailure
     Right ast -> do
       res <- return $ evalState (compileAll ast) startState
       case res of
         Right _ -> print ast
-        Left errs -> hPutStr stderr $ showErrorList errs
+        Left errs -> hPutStr stderr (showErrorList errs) >> exitFailure
+
+main :: IO ()
+main = do
+  progName <- getProgName
+  argv <- getArgs
+  case getOpt Permute options argv of
+    (o, n, []) ->
+      do
+        when (optHelp opts) $ usage progName []
+        when (optVersion opts) $ putStrLn (progName ++ " " ++ version) >> exitSuccess
+        case n of
+          [filename] -> compileFile filename
+          _ -> usage progName []
+      where
+        opts = foldl (flip id) defOptions o
+    (_, _, errs) -> usage progName errs