diff --git a/MonadLoc.hs b/MonadLoc.hs
--- a/MonadLoc.hs
+++ b/MonadLoc.hs
@@ -8,16 +8,37 @@
 
 main :: IO ()
 main = do
-  (fn:inp:outp:_) <- getArgs
-  Module l mhead opt imports decls <- fromParseResult <$>
-                                      parseFileWithMode ourParseMode{parseFilename = fn} inp
-  let mod'   = Module l mhead opt imports decls'
-      mname  = case mhead of
-                 Nothing -> ""
-                 Just (ModuleHead _ mn _ _) -> prettyPrint mn
-      decls' = map (annotateDecl mname) decls
-  writeFile outp $ prettyPrintStyleMode style{lineLength=100000} ourPrintMode mod'
+  args <- getArgs
+  case args of
 
+    (fn:inp:outp:_) -> do
+         Module l mhead opt imports decls
+            <- fromParseResult <$>
+               parseFileWithMode ourParseMode{parseFilename = fn} inp
+         let mod'   = Module l mhead opt imports decls'
+             mname  = case mhead of
+                        Nothing -> ""
+                        Just (ModuleHead _ mn _ _) -> prettyPrint mn
+             decls' = map (annotateDecl mname) decls
+         writeFile outp $ prettyPrintStyleMode style{lineLength=100000} ourPrintMode mod'
+--         writeFile outp $ exactPrint mod' []
+
+    [] -> do
+         contents <- getContents
+         let Module l mhead opt imports decls =
+              fromParseResult $
+              parseFileContentsWithMode ourParseMode contents
+         let mod'   = Module l mhead opt imports decls'
+             mname  = case mhead of
+                        Nothing -> ""
+                        Just (ModuleHead _ mn _ _) -> prettyPrint mn
+             decls' = map (annotateDecl mname) decls
+
+         putStrLn $ prettyPrintStyleMode style{lineLength=100000} ourPrintMode mod'
+
+    _ -> error "USAGE: MonadLoc expects the input from stdin and writes to stdout"
+
+
 ourParseMode :: ParseMode
 ourParseMode = defaultParseMode { extensions =
                                         [CPP
@@ -45,11 +66,13 @@
 ourPrintMode :: PPHsMode
 ourPrintMode = defaultMode { linePragmas = True }
 
+
 annotateDecl :: String -> Decl SrcSpanInfo -> Decl SrcSpanInfo
-annotateDecl mname e@(FunBind loc (m:_)) = everywhere (mkT (annotateStatements (Just funName) mname)) e
+annotateDecl mname e@(FunBind _ (m:_)) = everywhere (mkT (annotateStatements (Just funName) mname)) e
   where
-    funName | Match _ name _ _ _ <- m = prettyPrint name
-            | InfixMatch _ _ name _ _ _ <- m = prettyPrint name
+    funName = case m of
+              Match _ name _ _ _ -> prettyPrint name
+              InfixMatch _ _ name _ _ _ -> prettyPrint name
 
 annotateDecl mname e@(PatBind _ (PVar _ fn) _ _ _) = everywhere (mkT (annotateStatements (Just $ prettyPrint fn) mname)) e
 annotateDecl mname e = everywhere (mkT (annotateStatements Nothing mname)) e
@@ -71,7 +94,7 @@
    withLoc   = Qual loc (ModuleName loc "Control.Monad.Loc") (Ident loc "withLoc")
    srclocLit = String loc (render locString) ""
    locStringTail = text m <> parens(text (fileName loc)) <> colon <+> parens (int (startLine loc) <> comma <+> int(startColumn loc))
-   locString
-     | Nothing  <- fun = locStringTail
-     | Just fun <- fun = text fun <> comma <+> locStringTail
+   locString = case fun of
+                 Nothing  -> locStringTail
+                 Just fun -> text fun <> comma <+> locStringTail
 
diff --git a/monadloc.cabal b/monadloc.cabal
--- a/monadloc.cabal
+++ b/monadloc.cabal
@@ -1,5 +1,5 @@
 name: monadloc
-version: 0.1
+version: 0.2
 Cabal-Version:  >= 1.2.3
 build-type: Simple
 license: PublicDomain