[project @ 1999-01-07 12:47:34 by simonpj]

Add debug macro WARN

ghc/compiler/HsVersions.h

@@ -15,9 +15,11 @@ you will screw up the layout where they are used in case expressions!
 #ifdef DEBUG
 #define ASSERT(e) if (not (e)) then (assertPanic __FILE__ __LINE__) else
 #define ASSERT2(e,msg) if (not (e)) then (assertPprPanic __FILE__ __LINE__ (msg)) else
+#define WARN( e, msg ) (warnPprTrace (e) __FILE__ __LINE__ (msg))
 #else
 #define ASSERT(e)
 #define ASSERT2(e,msg)
+#define WARN(e,msg)
 #endif
 
 #if __STDC__

ghc/compiler/utils/Outputable.lhs

@@ -402,4 +402,12 @@ assertPprPanic file line msg
 		 	   text file, 
 			   text "line", int line], 
 		    msg]
+
+warnPprTrace :: Bool -> String -> Int -> SDoc -> a -> a
+warnPprTrace False file line msg x = x
+warnPprTrace True  file line msg x
+  = trace (show (doc PprDebug)) x
+  where
+    doc = sep [hsep [text "WARNING: file", text file, text "line", int line],
+	       msg]
 \end{code}