From 2f874c4c1d0cc861a8f72585a3e6f9673105b766 Mon Sep 17 00:00:00 2001
From: chak <unknown>
Date: Tue, 12 Feb 2002 03:52:09 +0000
Subject: [PATCH] [project @ 2002-02-12 03:52:08 by chak] This fixes a problem
 with the recent clean up in the parsing of type
 declarations.  The cleaned up version was correct by H98 (I
 think), but unfortunately won't compile the Prelude
 anymore.

I made the definition a little bit more liberal as follows:
- In `tycl_hdr' allow `gtycon' instead of just `tycon' for the defined type
  constructor.  This allows beyond H98 special syntax like "[]" etc as well as
  tycon ops in parenthesis.  Moreover, it allows qualified names, but the
  renamer flags the latter as errors.
- Allow `gtycon' instead of only `qtycon' for the class name in definitions of
  the form `Eq a => T a' to avoid a whole list of s/r conflicts.  (I have *not*
  checked that the renamer flags misuse, but I would expect that it does.)

ToDo: I think, the renamer should raise an error for all these additional
      forms *unless* -fglasgow-exts is given.

In PrelBase, I needed to replace the infix notation by prefix notation in the
definition of `:+:' and `:*:'.
---
 ghc/compiler/parser/Parser.y |   24 +++++++++++++++++-------
 ghc/lib/std/PrelBase.lhs     |    6 +++---
 2 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/ghc/compiler/parser/Parser.y b/ghc/compiler/parser/Parser.y
index e98b1ff..a478ec4 100644
--- a/ghc/compiler/parser/Parser.y
+++ b/ghc/compiler/parser/Parser.y
@@ -1,6 +1,6 @@
 {-								-*-haskell-*-
 -----------------------------------------------------------------------------
-$Id: Parser.y,v 1.86 2002/02/11 15:16:26 simonpj Exp $
+$Id: Parser.y,v 1.87 2002/02/12 03:52:08 chak Exp $
 
 Haskell grammar.
 
@@ -389,15 +389,25 @@ topdecl :: { RdrBinding }
 --	(Eq a, Ord b) => T a b
 -- Rather a lot of inlining here, else we get reduce/reduce errors
 tycl_hdr :: { (RdrNameContext, RdrName, [RdrNameHsTyVar]) }
-	: '(' comma_types1 ')' '=>' tycon tv_bndrs	{% mapP checkPred $2	`thenP` \ cxt ->
+	: '(' comma_types1 ')' '=>' gtycon tv_bndrs	{% mapP checkPred $2	`thenP` \ cxt ->
 							   returnP (cxt, $5, $6) }
-	| qtycon atypes1 '=>' tycon atypes0		{% checkTyVars $5	`thenP` \ tvs ->
+          -- qtycon for the class below name would lead to many s/r conflicts
+	  --   FIXME: does the renamer pick up all wrong forms and raise an
+	  --	      error 
+	| gtycon atypes1 '=>' gtycon atypes0		{% checkTyVars $5	`thenP` \ tvs ->
 						  	   returnP ([HsClassP $1 $2], $4, tvs) }
-	| qtycon  atypes0				{% checkTyVars $2	`thenP` \ tvs ->
+	| gtycon  atypes0				{% checkTyVars $2	`thenP` \ tvs ->
 						  	   returnP ([], $1, tvs) }
-		-- We have to have qtycon in this production to avoid s/r conflicts
-		-- with the previous one.  The renamer will complain if we use
-		-- a qualified tycon.
+		-- We have to have qtycon in this production to avoid s/r
+		-- conflicts with the previous one.  The renamer will complain
+		-- if we use a qualified tycon.
+		--
+		-- Using a `gtycon' throughout.  This enables special syntax,
+		-- such as "[]" for tycons as well as tycon ops in
+		-- parentheses.  This is beyond H98, but used repeatedly in
+		-- the Prelude modules.  (So, it would be a good idea to raise
+		-- an error in the renamer if some non-H98 form is used and
+		-- -fglasgow-exts is not given.)  -=chak 
 
 decls 	:: { [RdrBinding] }
 	: decls ';' decl		{ $3 : $1 }
diff --git a/ghc/lib/std/PrelBase.lhs b/ghc/lib/std/PrelBase.lhs
index 21ecfe0..f883948 100644
--- a/ghc/lib/std/PrelBase.lhs
+++ b/ghc/lib/std/PrelBase.lhs
@@ -1,5 +1,5 @@
 % -----------------------------------------------------------------------------
-% $Id: PrelBase.lhs,v 1.60 2002/01/29 09:58:19 simonpj Exp $
+% $Id: PrelBase.lhs,v 1.61 2002/02/12 03:52:09 chak Exp $
 %
 % (c) The University of Glasgow, 1992-2000
 %
@@ -599,8 +599,8 @@ instance CReturnable () -- Why, exactly?
 
 \begin{code}
 data Unit = Unit
-data a :+: b = Inl a | Inr b
-data a :*: b = a :*: b
+data (:+:) a b = Inl a | Inr b
+data (:*:) a b = a :*: b
 \end{code}
 
 
-- 
1.7.10.4