[Hat] Bug in hat-trans?

[Malcolm Wallace]

Magnus Carlsson <magnus@cse.ogi.edu> writes:

>   module Bug where f = \ ~(a,b) -> 1
> 
>   $ hmake -hat -nhc98 Bug.hs
>   hat-trans  Bug.hs
>   Wrote TBug.hs
>   nhc98    -c -package hat -o TBug.o TBug.hs
>   ======  Errors after type inference/checking:
>   Type error type clash between Hat.R and Prelude.->
>   when trying to apply function at 13:7 to its 4th argument at 14:10.

Ok, yes this is a bug.  Line 14 of the generated code has some
missing parentheses:
            (\ T.R ~(T.Tuple2 fa fb) _ p ->
should be:
            (\ (T.R ~(T.Tuple2 fa fb) _) p ->

The fix is in the code pretty-printer.  Patch attached.
Regards,
    Malcolm



Index: src/compiler98/PrettySyntax.hs
===================================================================
RCS file: /usr/src/master/nhc/src/compiler98/PrettySyntax.hs,v
retrieving revision 1.23
diff -u -r1.23 PrettySyntax.hs
--- src/compiler98/PrettySyntax.hs	2002/07/18 09:28:17	1.23
+++ src/compiler98/PrettySyntax.hs	2002/08/28 10:38:02
@@ -679,7 +679,7 @@
 
 ppExpPrec info withPar (ExpLambda pos pats e) =
   parenExp info pos withPar $
-    text "\\ " <> sep fSpace (map (ppExpPrec info False) pats) <>
+    text "\\ " <> sep fSpace (map (ppLambdaPat info) pats) <>
     text " ->" <> dSpace <> ppExpPrec info False e
 ppExpPrec info withPar (ExpDo pos stmts) =
   parenExp info pos withPar $
@@ -776,6 +776,11 @@
 ppExpPrec info withPar (PatNplusK pos n n' k _ _) =
   parenExp info pos withPar $
     ppIdAsVar info n <> fSpace <> text "+" <> fSpace <> ppExpPrec info True k 
+
+
+ppLambdaPat :: PPInfo a -> Exp a -> Doc
+ppLambdaPat info pat@(ExpApplication _ _) = ppExpPrec info True pat
+ppLambdaPat info pat                      = ppExpPrec info False pat
 
 
 ppField :: PPInfo a -> Field a -> Doc