From fca0bc2ca28f4551e073e14b2c36651d33d20b65 Mon Sep 17 00:00:00 2001
From: Matthijs Kooijman <m.kooijman@student.utwente.nl>
Date: Mon, 6 Apr 2009 13:39:50 +0200
Subject: [PATCH] Derive Show for more types.

In particular, this derives Show for all Outputable types, which requires
some ugly language pragma's (UndecidableTypes...). However, now HsExpr as
well as Type should be decently showable.
---
 CoreShow.hs | 45 +++++++++++++++++++++++++++++++++++++++------
 1 file changed, 39 insertions(+), 6 deletions(-)

diff --git a/CoreShow.hs b/CoreShow.hs
index 522fd39..35abd8b 100644
--- a/CoreShow.hs
+++ b/CoreShow.hs
@@ -1,22 +1,55 @@
-{-# LANGUAGE StandaloneDeriving #-}
+{-# LANGUAGE StandaloneDeriving,FlexibleInstances, UndecidableInstances, OverlappingInstances #-}
 module CoreShow where
 
 -- This module derives Show instances for CoreSyn types.
 
+import qualified BasicTypes
+
 import qualified CoreSyn
 import qualified TypeRep
+import qualified TyCon
+
+import qualified HsTypes
+import qualified HsExpr
+import qualified SrcLoc
+import qualified RdrName
 
-import Outputable ( showSDoc, ppr)
+import Outputable ( Outputable, OutputableBndr, showSDoc, ppr)
 
 
 -- Derive Show for core expressions and binders, so we can see the actual
 -- structure.
 deriving instance (Show b) => Show (CoreSyn.Expr b)
 deriving instance (Show b) => Show (CoreSyn.Bind b)
+deriving instance Show TypeRep.Type
+deriving instance (Show n, OutputableBndr n) => Show (HsTypes.HsType n)
+deriving instance (Show x) => Show (SrcLoc.Located x)
+deriving instance (Show x, OutputableBndr x) => Show (HsExpr.StmtLR x x)
+deriving instance (Show x, OutputableBndr x) => Show (HsExpr.HsExpr x)
+deriving instance Show (RdrName.RdrName)
+
 
--- Implement dummy shows for Note and Type, so we can at least use show on
--- expressions.
+-- Implement dummy shows, since deriving them will need loads of other shows
+-- as well.
 instance Show CoreSyn.Note where
   show n = "<note>"
-instance Show TypeRep.Type where
-  show t = "_type:(" ++ (showSDoc $ ppr t) ++ ")"
+instance Show TypeRep.PredType where
+  show t = "_PredType:(" ++ (showSDoc $ ppr t) ++ ")"
+instance Show TyCon.TyCon where
+  show t = "_TyCon:(" ++ (showSDoc $ ppr t) ++ ")"
+instance Show BasicTypes.Boxity where
+  show b = "_Boxity"
+instance Show HsTypes.HsExplicitForAll where
+  show b = "_HsExplicitForAll"
+instance Show HsExpr.HsArrAppType where
+  show b = "_HsArrAppType"
+instance Show (HsExpr.MatchGroup x) where
+  show b = "_HsMatchGroup"
+instance Show (HsExpr.GroupByClause x) where
+  show b = "_GroupByClause"
+instance Show (HsExpr.HsStmtContext x) where
+  show b = "_HsStmtContext"
+
+
+instance (Outputable x) => Show x where
+  show x = "__" ++  (showSDoc $ ppr x) ++ "__"
-- 
2.30.2