From: Ian Lynagh <igloo@earth.li>
Date: Fri, 4 Jul 2008 23:33:43 +0000 (+0000)
Subject: Improve error messages from pwd
X-Git-Tag: Before_cabalised-GHC~79
X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;h=ec05d3bbba14c9c022a9752819f7fd4aa9277e1c;hp=d5962639234c30fbfca3fa5845c8a03686bb8fb0;p=ghc-hetmet.git

Improve error messages from pwd
---

diff --git a/utils/pwd/pwd.hs b/utils/pwd/pwd.hs
index 264cc98..45a2d46 100644
--- a/utils/pwd/pwd.hs
+++ b/utils/pwd/pwd.hs
@@ -3,15 +3,21 @@ module Main where
 
 import System.Directory
 import System.Environment
+import System.Exit
+import System.IO
 
 main :: IO ()
-main = do args <- getArgs
-          let escape = case args of
-                       ["quadruple-backslash"] -> escape_quadruple_backslash
-                       ["forwardslash"] -> escape_forwardslash
-                       _ -> error ("pwd: Bad args: " ++ show args)
-          d <- getCurrentDirectory
-          putStr $ concatMap escape d
+main = do
+    args <- getArgs
+    escape <- case args of
+              ["quadruple-backslash"] -> return escape_quadruple_backslash
+              ["forwardslash"] ->        return escape_forwardslash
+              _ -> do hPutStrLn stderr ("Bad args: " ++ show args)
+                      hPutStrLn stderr
+                                "Usage: pwd {forwardslash|quadruple-backslash}"
+                      exitFailure
+    d <- getCurrentDirectory
+    putStr $ concatMap escape d
 
 -- In prog006 we have to escape \ twice, once to get through sed and
 -- again to get through parsing pkg.conf