Simple lexer/parser fixes.

hsrc/Main.hs

@@ -6,15 +6,38 @@ import System.Exit
 import System.IO.Error
 
 import Syntax.AST
+import Syntax.Lexer
 import Syntax.Parser
 import Syntax.ParserCore
 
 main :: IO ()
 main = do
-  [file] <- getArgs
-  ast <- loadModule file
-  putStrLn "Successful parse!"
-  putStrLn (show ast)
+  args <- getArgs
+  case args of
+    [file]        -> do
+      ast <- loadModule file
+      putStrLn "Successful parse!"
+      putStrLn (show ast)
+    ["-lex",path] -> do
+      mtxt <- tryJust (guard . isDoesNotExistError) $ S.readFile path
+      case mtxt of
+        Left _    -> fail $ "Unable to open file: " ++ path
+        Right txt -> do
+          case runParser path txt pullTokens of
+            Left err -> printError err >> exitWith (ExitFailure 1)
+            Right ress -> do
+              mapM_ putStrLn ress
+              putStrLn "Successful lex."
+
+pullTokens :: Parser [String]
+pullTokens = do
+  tok <- scan
+  case tok of
+    Lexeme pos tok -> do
+      let res = show pos ++ " " ++ show tok
+      if tok == TokEOF
+        then return [res]
+        else return (res :) `ap` pullTokens
 
 loadModule :: FilePath -> IO (Module ())
 loadModule path = do