[project @ 2004-05-19 08:46:21 by simonpj]

Improve error reporting for static flags

diff --git a/ghc/compiler/main/CmdLineOpts.lhs b/ghc/compiler/main/CmdLineOpts.lhs
index 6861620..a230e8d 100644 (file)
--- a/ghc/compiler/main/CmdLineOpts.lhs
+++ b/ghc/compiler/main/CmdLineOpts.lhs
@@ -104,6 +104,7 @@ import FastString   ( FastString, mkFastString )
 import Config
 import Maybes          ( firstJust )
 
+import Panic           ( ghcError, GhcException(UsageError) )
 import GLAEXTS
 import DATA_IOREF      ( IORef, readIORef, writeIORef )
 import UNSAFE_IO       ( unsafePerformIO )
@@ -708,19 +709,36 @@ packed_static_opts   = map mkFastString unpacked_static_opts
 
 lookUp     sw = sw `elem` packed_static_opts
        
-lookup_str sw = firstJust (map (startsWith sw) unpacked_static_opts)
+-- (lookup_str "foo") looks for the flag -foo=X or -fooX, 
+-- and returns the string X
+lookup_str sw 
+   = case firstJust (map (startsWith sw) unpacked_static_opts) of
+       Just ('=' : str) -> Just str
+       Just str         -> Just str
+       Nothing          -> Nothing     
 
 lookup_int sw = case (lookup_str sw) of
                  Nothing -> Nothing
-                 Just xx -> Just (read xx)
+                 Just xx -> Just (try_read sw xx)
 
 lookup_def_int sw def = case (lookup_str sw) of
                            Nothing -> def              -- Use default
-                           Just xx -> read xx
+                           Just xx -> try_read sw xx
 
 lookup_def_float sw def = case (lookup_str sw) of
                            Nothing -> def              -- Use default
-                           Just xx -> read xx
+                           Just xx -> try_read sw xx
+
+
+try_read :: Read a => String -> String -> a
+-- (try_read sw str) tries to read s; if it fails, it
+-- bleats about flag sw
+try_read sw str
+  = case reads str of
+       ((x,_):_) -> x  -- Be forgiving: ignore trailing goop, and alternative parses
+       []        -> ghcError (UsageError ("Malformed argument " ++ str ++ " for flag " ++ sw))
+                       -- ToDo: hack alert. We should really parse the arugments
+                       --       and announce errors in a more civilised way.
 
 
 {-