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.

diff --git a/CoreShow.hs b/CoreShow.hs
index 522fd39cb5c7277e817d50afc355ec5e2dd92da3..35abd8bf21bd373e3d2554359f9c9bbd9be244b6 100644 (file)
--- 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) ++ "__"