Supporting positional arguments

GetOpt.hs

@@ -19,22 +19,26 @@ import GetOpt.Parsers
 getOpt :: Parser a -> [String] -> Maybe (a, [String])
 getOpt (DefParser a) args = Just (a, args)
 getOpt p args = case runParser p args of
-                     Just (p1, args1) -> getOpt p1 args1
-                     Nothing          -> Nothing
+                     Just (p1@(OptParser _ _), args1) -> getOpt p1 args1
+                     Just (DefParser a, args1)        -> Just (a, args1)
+                     Nothing                          -> Nothing
 
 runParser :: Parser a -> [String] -> Maybe (Parser a, [String])
-runParser p@(DefParser _) args = Nothing
+runParser p@(DefParser _) args = Just (p, args)
 runParser (OptParser opt next) [] = do
     def <- defaultValue opt
     return (fmap def next, [])
-runParser (OptParser opt next) (identifier:args)
+runParser p@(OptParser opt next) (identifier:args)
     | optionMatch opt identifier = do
         (ret, lo) <- getArg opt args
         return (fmap ret next, lo)
+    | (DefParser _) <- next = do
+        (ret, lo) <- runParser p args
+        return (ret, identifier:lo)
     | otherwise = do
         (nextP, newArgs) <- runParser next (identifier:args)
         return (OptParser opt nextP, newArgs)
-    
+
     where
         getArg :: Option a -> [String] -> Maybe (a, [String])
         getArg opt (arg:args)